Batches

Create a Message Batch

post /v1/messages/batches

Send a batch of Message creation requests.

The Message Batches API can be used to process multiple Messages API requests at once. Once a Message Batch is created, it begins processing immediately. Batches can take up to 24 hours to complete.

Learn more about the Message Batches API in our user guide

Header Parameters

• "anthropic-beta": optional array of AnthropicBeta

  Optional header to specify the beta version(s) you want to use.

  • string

  • "message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 22 more

    • "message-batches-2024-09-24"

    • "prompt-caching-2024-07-31"

    • "computer-use-2024-10-22"

    • "computer-use-2025-01-24"

    • "pdfs-2024-09-25"

    • "token-counting-2024-11-01"

    • "token-efficient-tools-2025-02-19"

    • "output-128k-2025-02-19"

    • "files-api-2025-04-14"

    • "mcp-client-2025-04-04"

    • "mcp-client-2025-11-20"

    • "dev-full-thinking-2025-05-14"

    • "interleaved-thinking-2025-05-14"

    • "code-execution-2025-05-22"

    • "extended-cache-ttl-2025-04-11"

    • "context-1m-2025-08-07"

    • "context-management-2025-06-27"

    • "model-context-window-exceeded-2025-08-26"

    • "skills-2025-10-02"

    • "fast-mode-2026-02-01"

    • "output-300k-2026-03-24"

    • "user-profiles-2026-03-24"

    • "advisor-tool-2026-03-01"

    • "managed-agents-2026-04-01"

    • "cache-diagnosis-2026-04-07"

Body Parameters

• requests: array of object { custom_id, params }

  List of requests for prompt completion. Each is an individual request to create a Message.

  • custom_id: string

    Developer-provided ID created for each request in a Message Batch. Useful for matching results to requests, as results may be given out of request order.

    Must be unique for each request within the Message Batch.

  • params: object { max_tokens, messages, model, 21 more }

    Messages API creation parameters for the individual request.

    See the Messages API reference for full documentation on available parameters.

    • max_tokens: number

      The maximum number of tokens to generate before stopping.

      Note that our models may stop before reaching this maximum. This parameter only specifies the absolute maximum number of tokens to generate.

      Set to 0 to populate the prompt cache without generating a response.

      Different models have different maximum values for this parameter. See models for details.

    • messages: array of BetaMessageParam

      Input messages.

      Our models are trained to operate on alternating user and assistant conversational turns. When creating a new Message, you specify the prior conversational turns with the messages parameter, and the model then generates the next Message in the conversation. Consecutive user or assistant turns in your request will be combined into a single turn.

      Each input message must be an object with a role and content. You can specify a single user-role message, or you can include multiple user and assistant messages.

      If the final message uses the assistant role, the response content will continue immediately from the content in that message. This can be used to constrain part of the model's response.

      Example with a single user message:

      [{"role": "user", "content": "Hello, Claude"}]
      

      Example with multiple conversational turns:

      [
        {"role": "user", "content": "Hello there."},
        {"role": "assistant", "content": "Hi, I'm Claude. How can I help you?"},
        {"role": "user", "content": "Can you explain LLMs in plain English?"},
      ]
      

      Example with a partially-filled response from Claude:

      [
        {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
        {"role": "assistant", "content": "The best answer is ("},
      ]
      

      Each input message content may be either a single string or an array of content blocks, where each block has a specific type. Using a string for content is shorthand for an array of one content block of type "text". The following input messages are equivalent:

      {"role": "user", "content": "Hello, Claude"}
      

      {"role": "user", "content": [{"type": "text", "text": "Hello, Claude"}]}
      

      See input examples.

      Note that if you want to include a system prompt, you can use the top-level system parameter — there is no "system" role for input messages in the Messages API.

      There is a limit of 100,000 messages in a single request.

      • content: string or array of BetaContentBlockParam

        • string

        • array of BetaContentBlockParam

          • BetaTextBlockParam object { text, type, cache_control, citations }

            • text: string

            • type: "text"

              • "text"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

              • type: "ephemeral"

                • "ephemeral"

              • ttl: optional "5m" or "1h"

                The time-to-live for the cache control breakpoint.

                This may be one the following values:

                • 5m: 5 minutes
                • 1h: 1 hour

                Defaults to 5m.

                • "5m"

                • "1h"

            • citations: optional array of BetaTextCitationParam

              • BetaCitationCharLocationParam object { cited_text, document_index, document_title, 3 more }

                • cited_text: string

                • document_index: number

                • document_title: string

                • end_char_index: number

                • start_char_index: number

                • type: "char_location"

                  • "char_location"

              • BetaCitationPageLocationParam object { cited_text, document_index, document_title, 3 more }

                • cited_text: string

                • document_index: number

                • document_title: string

                • end_page_number: number

                • start_page_number: number

                • type: "page_location"

                  • "page_location"

              • BetaCitationContentBlockLocationParam object { cited_text, document_index, document_title, 3 more }

                • cited_text: string

                  The full text of the cited block range, concatenated.

                  Always equals the contents of content[start_block_index:end_block_index] joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                • document_index: number

                • document_title: string

                • end_block_index: number

                  Exclusive 0-based end index of the cited block range in the source's content array.

                  Always greater than start_block_index; a single-block citation has end_block_index = start_block_index + 1.

                • start_block_index: number

                  0-based index of the first cited block in the source's content array.

                • type: "content_block_location"

                  • "content_block_location"

              • BetaCitationWebSearchResultLocationParam object { cited_text, encrypted_index, title, 2 more }

                • cited_text: string

                • encrypted_index: string

                • title: string

                • type: "web_search_result_location"

                  • "web_search_result_location"

                • url: string

              • BetaCitationSearchResultLocationParam object { cited_text, end_block_index, search_result_index, 4 more }

                • cited_text: string

                  The full text of the cited block range, concatenated.

                  Always equals the contents of content[start_block_index:end_block_index] joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                • end_block_index: number

                  Exclusive 0-based end index of the cited block range in the source's content array.

                  Always greater than start_block_index; a single-block citation has end_block_index = start_block_index + 1.

                • search_result_index: number

                  0-based index of the cited search result among all search_result content blocks in the request, in the order they appear across messages and tool results.

                  Counted separately from document_index; server-side web search results are not included in this count.

                • source: string

                • start_block_index: number

                  0-based index of the first cited block in the source's content array.

                • title: string

                • type: "search_result_location"

                  • "search_result_location"

          • BetaImageBlockParam object { source, type, cache_control }

            • source: BetaBase64ImageSource or BetaURLImageSource or BetaFileImageSource

              • BetaBase64ImageSource object { data, media_type, type }

                • data: string

                • media_type: "image/jpeg" or "image/png" or "image/gif" or "image/webp"

                  • "image/jpeg"

                  • "image/png"

                  • "image/gif"

                  • "image/webp"

                • type: "base64"

                  • "base64"

              • BetaURLImageSource object { type, url }

                • type: "url"

                  • "url"

                • url: string

              • BetaFileImageSource object { file_id, type }

                • file_id: string

                • type: "file"

                  • "file"

            • type: "image"

              • "image"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

          • BetaRequestDocumentBlock object { source, type, cache_control, 3 more }

            • source: BetaBase64PDFSource or BetaPlainTextSource or BetaContentBlockSource or 2 more

              • BetaBase64PDFSource object { data, media_type, type }

                • data: string

                • media_type: "application/pdf"

                  • "application/pdf"

                • type: "base64"

                  • "base64"

              • BetaPlainTextSource object { data, media_type, type }

                • data: string

                • media_type: "text/plain"

                  • "text/plain"

                • type: "text"

                  • "text"

              • BetaContentBlockSource object { content, type }

                • content: string or array of BetaContentBlockSourceContent

                  • string

                  • BetaContentBlockSourceContent = array of BetaContentBlockSourceContent

                    • BetaTextBlockParam object { text, type, cache_control, citations }

                    • BetaImageBlockParam object { source, type, cache_control }

                • type: "content"

                  • "content"

              • BetaURLPDFSource object { type, url }

                • type: "url"

                  • "url"

                • url: string

              • BetaFileDocumentSource object { file_id, type }

                • file_id: string

                • type: "file"

                  • "file"

            • type: "document"

              • "document"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • citations: optional BetaCitationsConfigParam

              • enabled: optional boolean

            • context: optional string

            • title: optional string

          • BetaSearchResultBlockParam object { content, source, title, 3 more }

            • content: array of BetaTextBlockParam

              • text: string

              • type: "text"

              • cache_control: optional BetaCacheControlEphemeral

                Create a cache control breakpoint at this content block.

              • citations: optional array of BetaTextCitationParam

            • source: string

            • title: string

            • type: "search_result"

              • "search_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • citations: optional BetaCitationsConfigParam

          • BetaThinkingBlockParam object { signature, thinking, type }

            • signature: string

            • thinking: string

            • type: "thinking"

              • "thinking"

          • BetaRedactedThinkingBlockParam object { data, type }

            • data: string

            • type: "redacted_thinking"

              • "redacted_thinking"

          • BetaToolUseBlockParam object { id, input, name, 3 more }

            • id: string

            • input: map[unknown]

            • name: string

            • type: "tool_use"

              • "tool_use"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

                • type: "direct"

                  • "direct"

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

                • tool_id: string

                • type: "code_execution_20250825"

                  • "code_execution_20250825"

              • BetaServerToolCaller20260120 object { tool_id, type }

                • tool_id: string

                • type: "code_execution_20260120"

                  • "code_execution_20260120"

          • BetaToolResultBlockParam object { tool_use_id, type, cache_control, 2 more }

            • tool_use_id: string

            • type: "tool_result"

              • "tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • content: optional string or array of BetaTextBlockParam or BetaImageBlockParam or BetaSearchResultBlockParam or 2 more

              • string

              • array of BetaTextBlockParam or BetaImageBlockParam or BetaSearchResultBlockParam or 2 more

                • BetaTextBlockParam object { text, type, cache_control, citations }

                • BetaImageBlockParam object { source, type, cache_control }

                • BetaSearchResultBlockParam object { content, source, title, 3 more }

                • BetaRequestDocumentBlock object { source, type, cache_control, 3 more }

                • BetaToolReferenceBlockParam object { tool_name, type, cache_control }

                  Tool reference block that can be included in tool_result content.

                  • tool_name: string

                  • type: "tool_reference"

                    • "tool_reference"

                  • cache_control: optional BetaCacheControlEphemeral

                    Create a cache control breakpoint at this content block.

            • is_error: optional boolean

          • BetaServerToolUseBlockParam object { id, input, name, 3 more }

            • id: string

            • input: map[unknown]

            • name: "advisor" or "web_search" or "web_fetch" or 5 more

              • "advisor"

              • "web_search"

              • "web_fetch"

              • "code_execution"

              • "bash_code_execution"

              • "text_editor_code_execution"

              • "tool_search_tool_regex"

              • "tool_search_tool_bm25"

            • type: "server_tool_use"

              • "server_tool_use"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaWebSearchToolResultBlockParam object { content, tool_use_id, type, 2 more }

            • content: BetaWebSearchToolResultBlockParamContent

              • ResultBlock = array of BetaWebSearchResultBlockParam

                • encrypted_content: string

                • title: string

                • type: "web_search_result"

                  • "web_search_result"

                • url: string

                • page_age: optional string

              • BetaWebSearchToolRequestError object { error_code, type }

                • error_code: BetaWebSearchToolResultErrorCode

                  • "invalid_tool_input"

                  • "unavailable"

                  • "max_uses_exceeded"

                  • "too_many_requests"

                  • "query_too_long"

                  • "request_too_large"

                • type: "web_search_tool_result_error"

                  • "web_search_tool_result_error"

            • tool_use_id: string

            • type: "web_search_tool_result"

              • "web_search_tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaWebFetchToolResultBlockParam object { content, tool_use_id, type, 2 more }

            • content: BetaWebFetchToolResultErrorBlockParam or BetaWebFetchBlockParam

              • BetaWebFetchToolResultErrorBlockParam object { error_code, type }

                • error_code: BetaWebFetchToolResultErrorCode

                  • "invalid_tool_input"

                  • "url_too_long"

                  • "url_not_allowed"

                  • "url_not_accessible"

                  • "unsupported_content_type"

                  • "too_many_requests"

                  • "max_uses_exceeded"

                  • "unavailable"

                • type: "web_fetch_tool_result_error"

                  • "web_fetch_tool_result_error"

              • BetaWebFetchBlockParam object { content, type, url, retrieved_at }

                • content: BetaRequestDocumentBlock

                • type: "web_fetch_result"

                  • "web_fetch_result"

                • url: string

                  Fetched content URL

                • retrieved_at: optional string

                  ISO 8601 timestamp when the content was retrieved

            • tool_use_id: string

            • type: "web_fetch_tool_result"

              • "web_fetch_tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaAdvisorToolResultBlockParam object { content, tool_use_id, type, cache_control }

            • content: BetaAdvisorToolResultErrorParam or BetaAdvisorResultBlockParam or BetaAdvisorRedactedResultBlockParam

              • BetaAdvisorToolResultErrorParam object { error_code, type }

                • error_code: "max_uses_exceeded" or "prompt_too_long" or "too_many_requests" or 3 more

                  • "max_uses_exceeded"

                  • "prompt_too_long"

                  • "too_many_requests"

                  • "overloaded"

                  • "unavailable"

                  • "execution_time_exceeded"

                • type: "advisor_tool_result_error"

                  • "advisor_tool_result_error"

              • BetaAdvisorResultBlockParam object { text, type }

                • text: string

                • type: "advisor_result"

                  • "advisor_result"

              • BetaAdvisorRedactedResultBlockParam object { encrypted_content, type }

                • encrypted_content: string

                  Opaque blob produced by a prior response; must be round-tripped verbatim.

                • type: "advisor_redacted_result"

                  • "advisor_redacted_result"

            • tool_use_id: string

            • type: "advisor_tool_result"

              • "advisor_tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

          • BetaCodeExecutionToolResultBlockParam object { content, tool_use_id, type, cache_control }

            • content: BetaCodeExecutionToolResultBlockParamContent

              Code execution result with encrypted stdout for PFC + web_search results.

              • BetaCodeExecutionToolResultErrorParam object { error_code, type }

                • error_code: BetaCodeExecutionToolResultErrorCode

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                • type: "code_execution_tool_result_error"

                  • "code_execution_tool_result_error"

              • BetaCodeExecutionResultBlockParam object { content, return_code, stderr, 2 more }

                • content: array of BetaCodeExecutionOutputBlockParam

                  • file_id: string

                  • type: "code_execution_output"

                    • "code_execution_output"

                • return_code: number

                • stderr: string

                • stdout: string

                • type: "code_execution_result"

                  • "code_execution_result"

              • BetaEncryptedCodeExecutionResultBlockParam object { content, encrypted_stdout, return_code, 2 more }

                Code execution result with encrypted stdout for PFC + web_search results.

                • content: array of BetaCodeExecutionOutputBlockParam

                  • file_id: string

                  • type: "code_execution_output"

                • encrypted_stdout: string

                • return_code: number

                • stderr: string

                • type: "encrypted_code_execution_result"

                  • "encrypted_code_execution_result"

            • tool_use_id: string

            • type: "code_execution_tool_result"

              • "code_execution_tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

          • BetaBashCodeExecutionToolResultBlockParam object { content, tool_use_id, type, cache_control }

            • content: BetaBashCodeExecutionToolResultErrorParam or BetaBashCodeExecutionResultBlockParam

              • BetaBashCodeExecutionToolResultErrorParam object { error_code, type }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or 2 more

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                  • "output_file_too_large"

                • type: "bash_code_execution_tool_result_error"

                  • "bash_code_execution_tool_result_error"

              • BetaBashCodeExecutionResultBlockParam object { content, return_code, stderr, 2 more }

                • content: array of BetaBashCodeExecutionOutputBlockParam

                  • file_id: string

                  • type: "bash_code_execution_output"

                    • "bash_code_execution_output"

                • return_code: number

                • stderr: string

                • stdout: string

                • type: "bash_code_execution_result"

                  • "bash_code_execution_result"

            • tool_use_id: string

            • type: "bash_code_execution_tool_result"

              • "bash_code_execution_tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

          • BetaTextEditorCodeExecutionToolResultBlockParam object { content, tool_use_id, type, cache_control }

            • content: BetaTextEditorCodeExecutionToolResultErrorParam or BetaTextEditorCodeExecutionViewResultBlockParam or BetaTextEditorCodeExecutionCreateResultBlockParam or BetaTextEditorCodeExecutionStrReplaceResultBlockParam

              • BetaTextEditorCodeExecutionToolResultErrorParam object { error_code, type, error_message }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or 2 more

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                  • "file_not_found"

                • type: "text_editor_code_execution_tool_result_error"

                  • "text_editor_code_execution_tool_result_error"

                • error_message: optional string

              • BetaTextEditorCodeExecutionViewResultBlockParam object { content, file_type, type, 3 more }

                • content: string

                • file_type: "text" or "image" or "pdf"

                  • "text"

                  • "image"

                  • "pdf"

                • type: "text_editor_code_execution_view_result"

                  • "text_editor_code_execution_view_result"

                • num_lines: optional number

                • start_line: optional number

                • total_lines: optional number

              • BetaTextEditorCodeExecutionCreateResultBlockParam object { is_file_update, type }

                • is_file_update: boolean

                • type: "text_editor_code_execution_create_result"

                  • "text_editor_code_execution_create_result"

              • BetaTextEditorCodeExecutionStrReplaceResultBlockParam object { type, lines, new_lines, 3 more }

                • type: "text_editor_code_execution_str_replace_result"

                  • "text_editor_code_execution_str_replace_result"

                • lines: optional array of string

                • new_lines: optional number

                • new_start: optional number

                • old_lines: optional number

                • old_start: optional number

            • tool_use_id: string

            • type: "text_editor_code_execution_tool_result"

              • "text_editor_code_execution_tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

          • BetaToolSearchToolResultBlockParam object { content, tool_use_id, type, cache_control }

            • content: BetaToolSearchToolResultErrorParam or BetaToolSearchToolSearchResultBlockParam

              • BetaToolSearchToolResultErrorParam object { error_code, type }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or "execution_time_exceeded"

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                • type: "tool_search_tool_result_error"

                  • "tool_search_tool_result_error"

              • BetaToolSearchToolSearchResultBlockParam object { tool_references, type }

                • tool_references: array of BetaToolReferenceBlockParam

                  • tool_name: string

                  • type: "tool_reference"

                  • cache_control: optional BetaCacheControlEphemeral

                    Create a cache control breakpoint at this content block.

                • type: "tool_search_tool_search_result"

                  • "tool_search_tool_search_result"

            • tool_use_id: string

            • type: "tool_search_tool_result"

              • "tool_search_tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

          • BetaMCPToolUseBlockParam object { id, input, name, 3 more }

            • id: string

            • input: map[unknown]

            • name: string

            • server_name: string

              The name of the MCP server

            • type: "mcp_tool_use"

              • "mcp_tool_use"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

          • BetaRequestMCPToolResultBlockParam object { tool_use_id, type, cache_control, 2 more }

            • tool_use_id: string

            • type: "mcp_tool_result"

              • "mcp_tool_result"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • content: optional string or array of BetaTextBlockParam

              • string

              • BetaMCPToolResultBlockParamContent = array of BetaTextBlockParam

                • text: string

                • type: "text"

                • cache_control: optional BetaCacheControlEphemeral

                  Create a cache control breakpoint at this content block.

                • citations: optional array of BetaTextCitationParam

            • is_error: optional boolean

          • BetaContainerUploadBlockParam object { file_id, type, cache_control }

            A content block that represents a file to be uploaded to the container Files uploaded via this block will be available in the container's input directory.

            • file_id: string

            • type: "container_upload"

              • "container_upload"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

          • BetaCompactionBlockParam object { content, type, cache_control, encrypted_content }

            A compaction block containing summary of previous context.

            Users should round-trip these blocks from responses to subsequent requests to maintain context across compaction boundaries.

            When content is None, the block represents a failed compaction. The server treats these as no-ops. Empty string content is not allowed.

            • content: string

              Summary of previously compacted content, or null if compaction failed

            • type: "compaction"

              • "compaction"

            • cache_control: optional BetaCacheControlEphemeral

              Create a cache control breakpoint at this content block.

            • encrypted_content: optional string

              Opaque metadata from prior compaction, to be round-tripped verbatim

      • role: "user" or "assistant"

        • "user"

        • "assistant"

    • model: Model

      The model that will complete your prompt.

      See models for additional details and options.

      • "claude-opus-4-7" or "claude-mythos-preview" or "claude-opus-4-6" or 14 more

        The model that will complete your prompt.

        See models for additional details and options.

        • "claude-opus-4-7"

          Frontier intelligence for long-running agents and coding

        • "claude-mythos-preview"

          New class of intelligence, strongest in coding and cybersecurity

        • "claude-opus-4-6"

          Frontier intelligence for long-running agents and coding

        • "claude-sonnet-4-6"

          Best combination of speed and intelligence

        • "claude-haiku-4-5"

          Fastest model with near-frontier intelligence

        • "claude-haiku-4-5-20251001"

          Fastest model with near-frontier intelligence

        • "claude-opus-4-5"

          Premium model combining maximum intelligence with practical performance

        • "claude-opus-4-5-20251101"

          Premium model combining maximum intelligence with practical performance

        • "claude-sonnet-4-5"

          High-performance model for agents and coding

        • "claude-sonnet-4-5-20250929"

          High-performance model for agents and coding

        • "claude-opus-4-1"

          Exceptional model for specialized complex tasks

        • "claude-opus-4-1-20250805"

          Exceptional model for specialized complex tasks

        • "claude-opus-4-0"

          Powerful model for complex tasks

        • "claude-opus-4-20250514"

          Powerful model for complex tasks

        • "claude-sonnet-4-0"

          High-performance model with extended thinking

        • "claude-sonnet-4-20250514"

          High-performance model with extended thinking

        • "claude-3-haiku-20240307"

          Fast and cost-effective model

      • string

    • cache_control: optional BetaCacheControlEphemeral

      Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.

    • container: optional BetaContainerParams or string

      Container identifier for reuse across requests.

      • BetaContainerParams object { id, skills }

        Container parameters with skills to be loaded.

        • id: optional string

          Container id

        • skills: optional array of BetaSkillParams

          List of skills to load in the container

          • skill_id: string

            Skill ID

          • type: "anthropic" or "custom"

            Type of skill - either 'anthropic' (built-in) or 'custom' (user-defined)

            • "anthropic"

            • "custom"

          • version: optional string

            Skill version or 'latest' for most recent version

      • string

    • context_management: optional BetaContextManagementConfig

      Context management configuration.

      This allows you to control how Claude manages context across multiple requests, such as whether to clear function results or not.

      • edits: optional array of BetaClearToolUses20250919Edit or BetaClearThinking20251015Edit or BetaCompact20260112Edit

        List of context management edits to apply

        • BetaClearToolUses20250919Edit object { type, clear_at_least, clear_tool_inputs, 3 more }

          • type: "clear_tool_uses_20250919"

            • "clear_tool_uses_20250919"

          • clear_at_least: optional BetaInputTokensClearAtLeast

            Minimum number of tokens that must be cleared when triggered. Context will only be modified if at least this many tokens can be removed.

            • type: "input_tokens"

              • "input_tokens"

            • value: number

          • clear_tool_inputs: optional boolean or array of string

            Whether to clear all tool inputs (bool) or specific tool inputs to clear (list)

            • boolean

            • array of string

          • exclude_tools: optional array of string

            Tool names whose uses are preserved from clearing

          • keep: optional BetaToolUsesKeep

            Number of tool uses to retain in the conversation

            • type: "tool_uses"

              • "tool_uses"

            • value: number

          • trigger: optional BetaInputTokensTrigger or BetaToolUsesTrigger

            Condition that triggers the context management strategy

            • BetaInputTokensTrigger object { type, value }

              • type: "input_tokens"

                • "input_tokens"

              • value: number

            • BetaToolUsesTrigger object { type, value }

              • type: "tool_uses"

                • "tool_uses"

              • value: number

        • BetaClearThinking20251015Edit object { type, keep }

          • type: "clear_thinking_20251015"

            • "clear_thinking_20251015"

          • keep: optional BetaThinkingTurns or BetaAllThinkingTurns or "all"

            Number of most recent assistant turns to keep thinking blocks for. Older turns will have their thinking blocks removed.

            • BetaThinkingTurns object { type, value }

              • type: "thinking_turns"

                • "thinking_turns"

              • value: number

            • BetaAllThinkingTurns object { type }

              • type: "all"

                • "all"

            • "all"

              • "all"

        • BetaCompact20260112Edit object { type, instructions, pause_after_compaction, trigger }

          Automatically compact older context when reaching the configured trigger threshold.

          • type: "compact_20260112"

            • "compact_20260112"

          • instructions: optional string

            Additional instructions for summarization.

          • pause_after_compaction: optional boolean

            Whether to pause after compaction and return the compaction block to the user.

          • trigger: optional BetaInputTokensTrigger

            When to trigger compaction. Defaults to 150000 input tokens.

    • diagnostics: optional BetaDiagnosticsParam

      Request-level diagnostics. Currently carries the previous response id for prompt-cache divergence reporting.

      • previous_message_id: optional string

        The id (msg_...) from this client's previous /v1/messages response. The server compares that request's prompt fingerprint against this one and returns diagnostics.cache_miss_reason when the prompt-cache prefix could not be reused. Pass null on the first turn to opt in without a prior message to compare.

    • inference_geo: optional string

      Specifies the geographic region for inference processing. If not specified, the workspace's default_inference_geo is used.

    • mcp_servers: optional array of BetaRequestMCPServerURLDefinition

      MCP servers to be utilized in this request

      • name: string

      • type: "url"

        • "url"

      • url: string

      • authorization_token: optional string

      • tool_configuration: optional BetaRequestMCPServerToolConfiguration

        • allowed_tools: optional array of string

        • enabled: optional boolean

    • metadata: optional BetaMetadata

      An object describing metadata about the request.

      • user_id: optional string

        An external identifier for the user who is associated with the request.

        This should be a uuid, hash value, or other opaque identifier. Anthropic may use this id to help detect abuse. Do not include any identifying information such as name, email address, or phone number.

    • output_config: optional BetaOutputConfig

      Configuration options for the model's output, such as the output format.

      • effort: optional "low" or "medium" or "high" or 2 more

        All possible effort levels.

        • "low"

        • "medium"

        • "high"

        • "xhigh"

        • "max"

      • format: optional BetaJSONOutputFormat

        A schema to specify Claude's output format in responses. See structured outputs

        • schema: map[unknown]

          The JSON schema of the format

        • type: "json_schema"

          • "json_schema"

      • task_budget: optional BetaTokenTaskBudget

        User-configurable total token budget across contexts.

        • total: number

          Total token budget across all contexts in the session.

        • type: "tokens"

          The budget type. Currently only 'tokens' is supported.

          • "tokens"

        • remaining: optional number

          Remaining tokens in the budget. Use this to track usage across contexts when implementing compaction client-side. Defaults to total if not provided.

    • output_format: optional BetaJSONOutputFormat

      Deprecated: Use output_config.format instead. See structured outputs

      A schema to specify Claude's output format in responses. This parameter will be removed in a future release.

    • service_tier: optional "auto" or "standard_only"

      Determines whether to use priority capacity (if available) or standard capacity for this request.

      Anthropic offers different levels of service for your API requests. See service-tiers for details.

      • "auto"

      • "standard_only"

    • speed: optional "standard" or "fast"

      The inference speed mode for this request. "fast" enables high output-tokens-per-second inference.

      • "standard"

      • "fast"

    • stop_sequences: optional array of string

      Custom text sequences that will cause the model to stop generating.

      Our models will normally stop when they have naturally completed their turn, which will result in a response stop_reason of "end_turn".

      If you want the model to stop generating when it encounters custom strings of text, you can use the stop_sequences parameter. If the model encounters one of the custom sequences, the response stop_reason value will be "stop_sequence" and the response stop_sequence value will contain the matched stop sequence.

    • stream: optional boolean

      Whether to incrementally stream the response using server-sent events.

      See streaming for details.

    • system: optional string or array of BetaTextBlockParam

      System prompt.

      A system prompt is a way of providing context and instructions to Claude, such as specifying a particular goal or role. See our guide to system prompts.

      • string

      • array of BetaTextBlockParam

        • text: string

        • type: "text"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • citations: optional array of BetaTextCitationParam

    • temperature: optional number

      Amount of randomness injected into the response.

      Defaults to 1.0. Ranges from 0.0 to 1.0. Use temperature closer to 0.0 for analytical / multiple choice, and closer to 1.0 for creative and generative tasks.

      Note that even with temperature of 0.0, the results will not be fully deterministic.

    • thinking: optional BetaThinkingConfigParam

      Configuration for enabling Claude's extended thinking.

      When enabled, responses include thinking content blocks showing Claude's thinking process before the final answer. Requires a minimum budget of 1,024 tokens and counts towards your max_tokens limit.

      See extended thinking for details.

      • BetaThinkingConfigEnabled object { budget_tokens, type, display }

        • budget_tokens: number

          Determines how many tokens Claude can use for its internal reasoning process. Larger budgets can enable more thorough analysis for complex problems, improving response quality.

          Must be ≥1024 and less than max_tokens.

          See extended thinking for details.

        • type: "enabled"

          • "enabled"

        • display: optional "summarized" or "omitted"

          Controls how thinking content appears in the response. When set to summarized, thinking is returned normally. When set to omitted, thinking content is redacted but a signature is returned for multi-turn continuity. Defaults to summarized.

          • "summarized"

          • "omitted"

      • BetaThinkingConfigDisabled object { type }

        • type: "disabled"

          • "disabled"

      • BetaThinkingConfigAdaptive object { type, display }

        • type: "adaptive"

          • "adaptive"

        • display: optional "summarized" or "omitted"

          Controls how thinking content appears in the response. When set to summarized, thinking is returned normally. When set to omitted, thinking content is redacted but a signature is returned for multi-turn continuity. Defaults to summarized.

          • "summarized"

          • "omitted"

    • tool_choice: optional BetaToolChoice

      How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.

      • BetaToolChoiceAuto object { type, disable_parallel_tool_use }

        The model will automatically decide whether to use tools.

        • type: "auto"

          • "auto"

        • disable_parallel_tool_use: optional boolean

          Whether to disable parallel tool use.

          Defaults to false. If set to true, the model will output at most one tool use.

      • BetaToolChoiceAny object { type, disable_parallel_tool_use }

        The model will use any available tools.

        • type: "any"

          • "any"

        • disable_parallel_tool_use: optional boolean

          Whether to disable parallel tool use.

          Defaults to false. If set to true, the model will output exactly one tool use.

      • BetaToolChoiceTool object { name, type, disable_parallel_tool_use }

        The model will use the specified tool with tool_choice.name.

        • name: string

          The name of the tool to use.

        • type: "tool"

          • "tool"

        • disable_parallel_tool_use: optional boolean

          Whether to disable parallel tool use.

          Defaults to false. If set to true, the model will output exactly one tool use.

      • BetaToolChoiceNone object { type }

        The model will not be allowed to use tools.

        • type: "none"

          • "none"

    • tools: optional array of BetaToolUnion

      Definitions of tools that the model may use.

      If you include tools in your API request, the model may return tool_use content blocks that represent the model's use of those tools. You can then run those tools using the tool input generated by the model and then optionally return results back to the model using tool_result content blocks.

      There are two types of tools: client tools and server tools. The behavior described below applies to client tools. For server tools, see their individual documentation as each has its own behavior (e.g., the web search tool).

      Each tool definition includes:

      • name: Name of the tool.
      • description: Optional, but strongly-recommended description of the tool.
      • input_schema: JSON schema for the tool input shape that the model will produce in tool_use output content blocks.

      For example, if you defined tools as:

      [
        {
          "name": "get_stock_price",
          "description": "Get the current stock price for a given ticker symbol.",
          "input_schema": {
            "type": "object",
            "properties": {
              "ticker": {
                "type": "string",
                "description": "The stock ticker symbol, e.g. AAPL for Apple Inc."
              }
            },
            "required": ["ticker"]
          }
        }
      ]
      

      And then asked the model "What's the S&P 500 at today?", the model might produce tool_use content blocks in the response like this:

      [
        {
          "type": "tool_use",
          "id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
          "name": "get_stock_price",
          "input": { "ticker": "^GSPC" }
        }
      ]
      

      You might then run your get_stock_price tool with {"ticker": "^GSPC"} as an input, and return the following back to the model in a subsequent user message:

      [
        {
          "type": "tool_result",
          "tool_use_id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
          "content": "259.75 USD"
        }
      ]
      

      Tools can be used for workflows that include running client-side tools and functions, or more generally whenever you want the model to produce a particular JSON structure of output.

      See our guide for more details.

      • BetaTool object { input_schema, name, allowed_callers, 7 more }

        • input_schema: object { type, properties, required }

          JSON schema for this tool's input.

          This defines the shape of the input that your tool accepts and that the model will produce.

          • type: "object"

            • "object"

          • properties: optional map[unknown]

          • required: optional array of string

        • name: string

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • description: optional string

          Description of what this tool does.

          Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema.

        • eager_input_streaming: optional boolean

          Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

        • type: optional "custom"

          • "custom"

      • BetaToolBash20241022 object { name, type, allowed_callers, 4 more }

        • name: "bash"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "bash"

        • type: "bash_20241022"

          • "bash_20241022"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolBash20250124 object { name, type, allowed_callers, 4 more }

        • name: "bash"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "bash"

        • type: "bash_20250124"

          • "bash_20250124"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaCodeExecutionTool20250522 object { name, type, allowed_callers, 3 more }

        • name: "code_execution"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "code_execution"

        • type: "code_execution_20250522"

          • "code_execution_20250522"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaCodeExecutionTool20250825 object { name, type, allowed_callers, 3 more }

        • name: "code_execution"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "code_execution"

        • type: "code_execution_20250825"

          • "code_execution_20250825"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaCodeExecutionTool20260120 object { name, type, allowed_callers, 3 more }

        Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

        • name: "code_execution"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "code_execution"

        • type: "code_execution_20260120"

          • "code_execution_20260120"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolComputerUse20241022 object { display_height_px, display_width_px, name, 7 more }

        • display_height_px: number

          The height of the display in pixels.

        • display_width_px: number

          The width of the display in pixels.

        • name: "computer"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "computer"

        • type: "computer_20241022"

          • "computer_20241022"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • display_number: optional number

          The X11 display number (e.g. 0, 1) for the display.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaMemoryTool20250818 object { name, type, allowed_callers, 4 more }

        • name: "memory"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "memory"

        • type: "memory_20250818"

          • "memory_20250818"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolComputerUse20250124 object { display_height_px, display_width_px, name, 7 more }

        • display_height_px: number

          The height of the display in pixels.

        • display_width_px: number

          The width of the display in pixels.

        • name: "computer"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "computer"

        • type: "computer_20250124"

          • "computer_20250124"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • display_number: optional number

          The X11 display number (e.g. 0, 1) for the display.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolTextEditor20241022 object { name, type, allowed_callers, 4 more }

        • name: "str_replace_editor"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "str_replace_editor"

        • type: "text_editor_20241022"

          • "text_editor_20241022"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolComputerUse20251124 object { display_height_px, display_width_px, name, 8 more }

        • display_height_px: number

          The height of the display in pixels.

        • display_width_px: number

          The width of the display in pixels.

        • name: "computer"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "computer"

        • type: "computer_20251124"

          • "computer_20251124"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • display_number: optional number

          The X11 display number (e.g. 0, 1) for the display.

        • enable_zoom: optional boolean

          Whether to enable an action to take a zoomed-in screenshot of the screen.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolTextEditor20250124 object { name, type, allowed_callers, 4 more }

        • name: "str_replace_editor"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "str_replace_editor"

        • type: "text_editor_20250124"

          • "text_editor_20250124"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolTextEditor20250429 object { name, type, allowed_callers, 4 more }

        • name: "str_replace_based_edit_tool"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "str_replace_based_edit_tool"

        • type: "text_editor_20250429"

          • "text_editor_20250429"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • input_examples: optional array of map[unknown]

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolTextEditor20250728 object { name, type, allowed_callers, 5 more }

        • name: "str_replace_based_edit_tool"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "str_replace_based_edit_tool"

        • type: "text_editor_20250728"

          • "text_editor_20250728"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • input_examples: optional array of map[unknown]

        • max_characters: optional number

          Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaWebSearchTool20250305 object { name, type, allowed_callers, 7 more }

        • name: "web_search"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "web_search"

        • type: "web_search_20250305"

          • "web_search_20250305"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • allowed_domains: optional array of string

          If provided, only these domains will be included in results. Cannot be used alongside blocked_domains.

        • blocked_domains: optional array of string

          If provided, these domains will never appear in results. Cannot be used alongside allowed_domains.

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • max_uses: optional number

          Maximum number of times the tool can be used in the API request.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

        • user_location: optional BetaUserLocation

          Parameters for the user's location. Used to provide more relevant search results.

          • type: "approximate"

            • "approximate"

          • city: optional string

            The city of the user.

          • country: optional string

            The two letter ISO country code of the user.

          • region: optional string

            The region of the user.

          • timezone: optional string

            The IANA timezone of the user.

      • BetaWebFetchTool20250910 object { name, type, allowed_callers, 8 more }

        • name: "web_fetch"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "web_fetch"

        • type: "web_fetch_20250910"

          • "web_fetch_20250910"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • allowed_domains: optional array of string

          List of domains to allow fetching from

        • blocked_domains: optional array of string

          List of domains to block fetching from

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • citations: optional BetaCitationsConfigParam

          Citations configuration for fetched documents. Citations are disabled by default.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • max_content_tokens: optional number

          Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

        • max_uses: optional number

          Maximum number of times the tool can be used in the API request.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaWebSearchTool20260209 object { name, type, allowed_callers, 7 more }

        • name: "web_search"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "web_search"

        • type: "web_search_20260209"

          • "web_search_20260209"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • allowed_domains: optional array of string

          If provided, only these domains will be included in results. Cannot be used alongside blocked_domains.

        • blocked_domains: optional array of string

          If provided, these domains will never appear in results. Cannot be used alongside allowed_domains.

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • max_uses: optional number

          Maximum number of times the tool can be used in the API request.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

        • user_location: optional BetaUserLocation

          Parameters for the user's location. Used to provide more relevant search results.

      • BetaWebFetchTool20260209 object { name, type, allowed_callers, 8 more }

        • name: "web_fetch"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "web_fetch"

        • type: "web_fetch_20260209"

          • "web_fetch_20260209"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • allowed_domains: optional array of string

          List of domains to allow fetching from

        • blocked_domains: optional array of string

          List of domains to block fetching from

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • citations: optional BetaCitationsConfigParam

          Citations configuration for fetched documents. Citations are disabled by default.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • max_content_tokens: optional number

          Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

        • max_uses: optional number

          Maximum number of times the tool can be used in the API request.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaWebFetchTool20260309 object { name, type, allowed_callers, 9 more }

        Web fetch tool with use_cache parameter for bypassing cached content.

        • name: "web_fetch"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "web_fetch"

        • type: "web_fetch_20260309"

          • "web_fetch_20260309"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • allowed_domains: optional array of string

          List of domains to allow fetching from

        • blocked_domains: optional array of string

          List of domains to block fetching from

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • citations: optional BetaCitationsConfigParam

          Citations configuration for fetched documents. Citations are disabled by default.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • max_content_tokens: optional number

          Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

        • max_uses: optional number

          Maximum number of times the tool can be used in the API request.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

        • use_cache: optional boolean

          Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

      • BetaAdvisorTool20260301 object { model, name, type, 6 more }

        • model: Model

          The model that will complete your prompt.

          See models for additional details and options.

        • name: "advisor"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "advisor"

        • type: "advisor_20260301"

          • "advisor_20260301"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • caching: optional BetaCacheControlEphemeral

          Caching for the advisor's own prompt. When set, each advisor call writes a cache entry at the given TTL so subsequent calls in the same conversation read the stable prefix. When omitted, the advisor prompt is not cached.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • max_uses: optional number

          Maximum number of times the tool can be used in the API request.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolSearchToolBm25_20251119 object { name, type, allowed_callers, 3 more }

        • name: "tool_search_tool_bm25"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "tool_search_tool_bm25"

        • type: "tool_search_tool_bm25_20251119" or "tool_search_tool_bm25"

          • "tool_search_tool_bm25_20251119"

          • "tool_search_tool_bm25"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaToolSearchToolRegex20251119 object { name, type, allowed_callers, 3 more }

        • name: "tool_search_tool_regex"

          Name of the tool.

          This is how the tool will be called by the model and in tool_use blocks.

          • "tool_search_tool_regex"

        • type: "tool_search_tool_regex_20251119" or "tool_search_tool_regex"

          • "tool_search_tool_regex_20251119"

          • "tool_search_tool_regex"

        • allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120"

          • "direct"

          • "code_execution_20250825"

          • "code_execution_20260120"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • defer_loading: optional boolean

          If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

        • strict: optional boolean

          When true, guarantees schema validation on tool names and inputs

      • BetaMCPToolset object { mcp_server_name, type, cache_control, 2 more }

        Configuration for a group of tools from an MCP server.

        Allows configuring enabled status and defer_loading for all tools from an MCP server, with optional per-tool overrides.

        • mcp_server_name: string

          Name of the MCP server to configure tools for

        • type: "mcp_toolset"

          • "mcp_toolset"

        • cache_control: optional BetaCacheControlEphemeral

          Create a cache control breakpoint at this content block.

        • configs: optional map[BetaMCPToolConfig]

          Configuration overrides for specific tools, keyed by tool name

          • defer_loading: optional boolean

          • enabled: optional boolean

        • default_config: optional BetaMCPToolDefaultConfig

          Default configuration applied to all tools from this server

          • defer_loading: optional boolean

          • enabled: optional boolean

    • top_k: optional number

      Only sample from the top K options for each subsequent token.

      Used to remove "long tail" low probability responses. Learn more technical details here.

      Recommended for advanced use cases only.

    • top_p: optional number

      Use nucleus sampling.

      In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by top_p.

      Recommended for advanced use cases only.

    • user_profile_id: optional string

      The user profile ID to attribute this request to. Use when acting on behalf of a party other than your organization.

Returns

• BetaMessageBatch object { id, archived_at, cancel_initiated_at, 7 more }

  • id: string

    Unique object identifier.

    The format and length of IDs may change over time.

  • archived_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  • cancel_initiated_at: string

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  • created_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  • ended_at: string

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  • expires_at: string

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  • processing_status: "in_progress" or "canceling" or "ended"

    Processing status of the Message Batch.

    • "in_progress"

    • "canceling"

    • "ended"

  • request_counts: BetaMessageBatchRequestCounts

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as processing and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    • canceled: number

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    • errored: number

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    • expired: number

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    • processing: number

      Number of requests in the Message Batch that are processing.

    • succeeded: number

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  • results_url: string

    URL to a .jsonl file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the custom_id field to match results to requests.

  • type: "message_batch"

    Object type.

    For Message Batches, this is always "message_batch".

    • "message_batch"

Example

curl https://api.anthropic.com/v1/messages/batches \
    -H 'Content-Type: application/json' \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: message-batches-2024-09-24' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY" \
    -d '{
          "requests": [
            {
              "custom_id": "my-custom-id-1",
              "params": {
                "max_tokens": 1024,
                "messages": [
                  {
                    "content": "Hello, world",
                    "role": "user"
                  }
                ],
                "model": "claude-opus-4-6"
              }
            }
          ]
        }'

Response

{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "archived_at": "2024-08-20T18:37:24.100435Z",
  "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
  "created_at": "2024-08-20T18:37:24.100435Z",
  "ended_at": "2024-08-20T18:37:24.100435Z",
  "expires_at": "2024-08-20T18:37:24.100435Z",
  "processing_status": "in_progress",
  "request_counts": {
    "canceled": 10,
    "errored": 30,
    "expired": 10,
    "processing": 100,
    "succeeded": 50
  },
  "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results",
  "type": "message_batch"
}

Retrieve a Message Batch

get /v1/messages/batches/{message_batch_id}

This endpoint is idempotent and can be used to poll for Message Batch completion. To access the results of a Message Batch, make a request to the results_url field in the response.

Learn more about the Message Batches API in our user guide

Path Parameters

• message_batch_id: string

  ID of the Message Batch.

Header Parameters

• "anthropic-beta": optional array of AnthropicBeta

  Optional header to specify the beta version(s) you want to use.

  • string

  • "message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 22 more

    • "message-batches-2024-09-24"

    • "prompt-caching-2024-07-31"

    • "computer-use-2024-10-22"

    • "computer-use-2025-01-24"

    • "pdfs-2024-09-25"

    • "token-counting-2024-11-01"

    • "token-efficient-tools-2025-02-19"

    • "output-128k-2025-02-19"

    • "files-api-2025-04-14"

    • "mcp-client-2025-04-04"

    • "mcp-client-2025-11-20"

    • "dev-full-thinking-2025-05-14"

    • "interleaved-thinking-2025-05-14"

    • "code-execution-2025-05-22"

    • "extended-cache-ttl-2025-04-11"

    • "context-1m-2025-08-07"

    • "context-management-2025-06-27"

    • "model-context-window-exceeded-2025-08-26"

    • "skills-2025-10-02"

    • "fast-mode-2026-02-01"

    • "output-300k-2026-03-24"

    • "user-profiles-2026-03-24"

    • "advisor-tool-2026-03-01"

    • "managed-agents-2026-04-01"

    • "cache-diagnosis-2026-04-07"

Returns

• BetaMessageBatch object { id, archived_at, cancel_initiated_at, 7 more }

  • id: string

    Unique object identifier.

    The format and length of IDs may change over time.

  • archived_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  • cancel_initiated_at: string

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  • created_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  • ended_at: string

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  • expires_at: string

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  • processing_status: "in_progress" or "canceling" or "ended"

    Processing status of the Message Batch.

    • "in_progress"

    • "canceling"

    • "ended"

  • request_counts: BetaMessageBatchRequestCounts

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as processing and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    • canceled: number

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    • errored: number

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    • expired: number

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    • processing: number

      Number of requests in the Message Batch that are processing.

    • succeeded: number

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  • results_url: string

    URL to a .jsonl file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the custom_id field to match results to requests.

  • type: "message_batch"

    Object type.

    For Message Batches, this is always "message_batch".

    • "message_batch"

Example

curl https://api.anthropic.com/v1/messages/batches/$MESSAGE_BATCH_ID \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: message-batches-2024-09-24' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY"

Response

{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "archived_at": "2024-08-20T18:37:24.100435Z",
  "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
  "created_at": "2024-08-20T18:37:24.100435Z",
  "ended_at": "2024-08-20T18:37:24.100435Z",
  "expires_at": "2024-08-20T18:37:24.100435Z",
  "processing_status": "in_progress",
  "request_counts": {
    "canceled": 10,
    "errored": 30,
    "expired": 10,
    "processing": 100,
    "succeeded": 50
  },
  "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results",
  "type": "message_batch"
}

List Message Batches

get /v1/messages/batches

List all Message Batches within a Workspace. Most recently created batches are returned first.

Learn more about the Message Batches API in our user guide

Query Parameters

• after_id: optional string

  ID of the object to use as a cursor for pagination. When provided, returns the page of results immediately after this object.

• before_id: optional string

  ID of the object to use as a cursor for pagination. When provided, returns the page of results immediately before this object.

• limit: optional number

  Number of items to return per page.

  Defaults to 20. Ranges from 1 to 1000.

Header Parameters

• "anthropic-beta": optional array of AnthropicBeta

  Optional header to specify the beta version(s) you want to use.

  • string

  • "message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 22 more

    • "message-batches-2024-09-24"

    • "prompt-caching-2024-07-31"

    • "computer-use-2024-10-22"

    • "computer-use-2025-01-24"

    • "pdfs-2024-09-25"

    • "token-counting-2024-11-01"

    • "token-efficient-tools-2025-02-19"

    • "output-128k-2025-02-19"

    • "files-api-2025-04-14"

    • "mcp-client-2025-04-04"

    • "mcp-client-2025-11-20"

    • "dev-full-thinking-2025-05-14"

    • "interleaved-thinking-2025-05-14"

    • "code-execution-2025-05-22"

    • "extended-cache-ttl-2025-04-11"

    • "context-1m-2025-08-07"

    • "context-management-2025-06-27"

    • "model-context-window-exceeded-2025-08-26"

    • "skills-2025-10-02"

    • "fast-mode-2026-02-01"

    • "output-300k-2026-03-24"

    • "user-profiles-2026-03-24"

    • "advisor-tool-2026-03-01"

    • "managed-agents-2026-04-01"

    • "cache-diagnosis-2026-04-07"

Returns

• data: array of BetaMessageBatch

  • id: string

    Unique object identifier.

    The format and length of IDs may change over time.

  • archived_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  • cancel_initiated_at: string

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  • created_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  • ended_at: string

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  • expires_at: string

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  • processing_status: "in_progress" or "canceling" or "ended"

    Processing status of the Message Batch.

    • "in_progress"

    • "canceling"

    • "ended"

  • request_counts: BetaMessageBatchRequestCounts

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as processing and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    • canceled: number

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    • errored: number

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    • expired: number

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    • processing: number

      Number of requests in the Message Batch that are processing.

    • succeeded: number

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  • results_url: string

    URL to a .jsonl file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the custom_id field to match results to requests.

  • type: "message_batch"

    Object type.

    For Message Batches, this is always "message_batch".

    • "message_batch"

• first_id: string

  First ID in the data list. Can be used as the before_id for the previous page.

• has_more: boolean

  Indicates if there are more results in the requested page direction.

• last_id: string

  Last ID in the data list. Can be used as the after_id for the next page.

Example

curl https://api.anthropic.com/v1/messages/batches \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: message-batches-2024-09-24' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY"

Response

{
  "data": [
    {
      "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
      "archived_at": "2024-08-20T18:37:24.100435Z",
      "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
      "created_at": "2024-08-20T18:37:24.100435Z",
      "ended_at": "2024-08-20T18:37:24.100435Z",
      "expires_at": "2024-08-20T18:37:24.100435Z",
      "processing_status": "in_progress",
      "request_counts": {
        "canceled": 10,
        "errored": 30,
        "expired": 10,
        "processing": 100,
        "succeeded": 50
      },
      "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results",
      "type": "message_batch"
    }
  ],
  "first_id": "first_id",
  "has_more": true,
  "last_id": "last_id"
}

Cancel a Message Batch

post /v1/messages/batches/{message_batch_id}/cancel

Batches may be canceled any time before processing ends. Once cancellation is initiated, the batch enters a canceling state, at which time the system may complete any in-progress, non-interruptible requests before finalizing cancellation.

The number of canceled requests is specified in request_counts. To determine which requests were canceled, check the individual results within the batch. Note that cancellation may not result in any canceled requests if they were non-interruptible.

Learn more about the Message Batches API in our user guide

Path Parameters

• message_batch_id: string

  ID of the Message Batch.

Header Parameters

• "anthropic-beta": optional array of AnthropicBeta

  Optional header to specify the beta version(s) you want to use.

  • string

  • "message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 22 more

    • "message-batches-2024-09-24"

    • "prompt-caching-2024-07-31"

    • "computer-use-2024-10-22"

    • "computer-use-2025-01-24"

    • "pdfs-2024-09-25"

    • "token-counting-2024-11-01"

    • "token-efficient-tools-2025-02-19"

    • "output-128k-2025-02-19"

    • "files-api-2025-04-14"

    • "mcp-client-2025-04-04"

    • "mcp-client-2025-11-20"

    • "dev-full-thinking-2025-05-14"

    • "interleaved-thinking-2025-05-14"

    • "code-execution-2025-05-22"

    • "extended-cache-ttl-2025-04-11"

    • "context-1m-2025-08-07"

    • "context-management-2025-06-27"

    • "model-context-window-exceeded-2025-08-26"

    • "skills-2025-10-02"

    • "fast-mode-2026-02-01"

    • "output-300k-2026-03-24"

    • "user-profiles-2026-03-24"

    • "advisor-tool-2026-03-01"

    • "managed-agents-2026-04-01"

    • "cache-diagnosis-2026-04-07"

Returns

• BetaMessageBatch object { id, archived_at, cancel_initiated_at, 7 more }

  • id: string

    Unique object identifier.

    The format and length of IDs may change over time.

  • archived_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  • cancel_initiated_at: string

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  • created_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  • ended_at: string

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  • expires_at: string

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  • processing_status: "in_progress" or "canceling" or "ended"

    Processing status of the Message Batch.

    • "in_progress"

    • "canceling"

    • "ended"

  • request_counts: BetaMessageBatchRequestCounts

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as processing and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    • canceled: number

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    • errored: number

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    • expired: number

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    • processing: number

      Number of requests in the Message Batch that are processing.

    • succeeded: number

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  • results_url: string

    URL to a .jsonl file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the custom_id field to match results to requests.

  • type: "message_batch"

    Object type.

    For Message Batches, this is always "message_batch".

    • "message_batch"

Example

curl https://api.anthropic.com/v1/messages/batches/$MESSAGE_BATCH_ID/cancel \
    -X POST \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: message-batches-2024-09-24' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY"

Response

{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "archived_at": "2024-08-20T18:37:24.100435Z",
  "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
  "created_at": "2024-08-20T18:37:24.100435Z",
  "ended_at": "2024-08-20T18:37:24.100435Z",
  "expires_at": "2024-08-20T18:37:24.100435Z",
  "processing_status": "in_progress",
  "request_counts": {
    "canceled": 10,
    "errored": 30,
    "expired": 10,
    "processing": 100,
    "succeeded": 50
  },
  "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results",
  "type": "message_batch"
}

Delete a Message Batch

delete /v1/messages/batches/{message_batch_id}

Delete a Message Batch.

Message Batches can only be deleted once they've finished processing. If you'd like to delete an in-progress batch, you must first cancel it.

Learn more about the Message Batches API in our user guide

Path Parameters

• message_batch_id: string

  ID of the Message Batch.

Header Parameters

• "anthropic-beta": optional array of AnthropicBeta

  Optional header to specify the beta version(s) you want to use.

  • string

  • "message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 22 more

    • "message-batches-2024-09-24"

    • "prompt-caching-2024-07-31"

    • "computer-use-2024-10-22"

    • "computer-use-2025-01-24"

    • "pdfs-2024-09-25"

    • "token-counting-2024-11-01"

    • "token-efficient-tools-2025-02-19"

    • "output-128k-2025-02-19"

    • "files-api-2025-04-14"

    • "mcp-client-2025-04-04"

    • "mcp-client-2025-11-20"

    • "dev-full-thinking-2025-05-14"

    • "interleaved-thinking-2025-05-14"

    • "code-execution-2025-05-22"

    • "extended-cache-ttl-2025-04-11"

    • "context-1m-2025-08-07"

    • "context-management-2025-06-27"

    • "model-context-window-exceeded-2025-08-26"

    • "skills-2025-10-02"

    • "fast-mode-2026-02-01"

    • "output-300k-2026-03-24"

    • "user-profiles-2026-03-24"

    • "advisor-tool-2026-03-01"

    • "managed-agents-2026-04-01"

    • "cache-diagnosis-2026-04-07"

Returns

• BetaDeletedMessageBatch object { id, type }

  • id: string

    ID of the Message Batch.

  • type: "message_batch_deleted"

    Deleted object type.

    For Message Batches, this is always "message_batch_deleted".

    • "message_batch_deleted"

Example

curl https://api.anthropic.com/v1/messages/batches/$MESSAGE_BATCH_ID \
    -X DELETE \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: message-batches-2024-09-24' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY"

Response

{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "type": "message_batch_deleted"
}

Retrieve Message Batch results

get /v1/messages/batches/{message_batch_id}/results

Streams the results of a Message Batch as a .jsonl file.

Each line in the file is a JSON object containing the result of a single request in the Message Batch. Results are not guaranteed to be in the same order as requests. Use the custom_id field to match results to requests.

Learn more about the Message Batches API in our user guide

Path Parameters

• message_batch_id: string

  ID of the Message Batch.

Header Parameters

• "anthropic-beta": optional array of AnthropicBeta

  Optional header to specify the beta version(s) you want to use.

  • string

  • "message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 22 more

    • "message-batches-2024-09-24"

    • "prompt-caching-2024-07-31"

    • "computer-use-2024-10-22"

    • "computer-use-2025-01-24"

    • "pdfs-2024-09-25"

    • "token-counting-2024-11-01"

    • "token-efficient-tools-2025-02-19"

    • "output-128k-2025-02-19"

    • "files-api-2025-04-14"

    • "mcp-client-2025-04-04"

    • "mcp-client-2025-11-20"

    • "dev-full-thinking-2025-05-14"

    • "interleaved-thinking-2025-05-14"

    • "code-execution-2025-05-22"

    • "extended-cache-ttl-2025-04-11"

    • "context-1m-2025-08-07"

    • "context-management-2025-06-27"

    • "model-context-window-exceeded-2025-08-26"

    • "skills-2025-10-02"

    • "fast-mode-2026-02-01"

    • "output-300k-2026-03-24"

    • "user-profiles-2026-03-24"

    • "advisor-tool-2026-03-01"

    • "managed-agents-2026-04-01"

    • "cache-diagnosis-2026-04-07"

Returns

• BetaMessageBatchIndividualResponse object { custom_id, result }

  This is a single line in the response .jsonl file and does not represent the response as a whole.

  • custom_id: string

    Developer-provided ID created for each request in a Message Batch. Useful for matching results to requests, as results may be given out of request order.

    Must be unique for each request within the Message Batch.

  • result: BetaMessageBatchResult

    Processing result for this request.

    Contains a Message output if processing was successful, an error response if processing failed, or the reason why processing was not attempted, such as cancellation or expiration.

    • BetaMessageBatchSucceededResult object { message, type }

      • message: BetaMessage

        • id: string

          Unique object identifier.

          The format and length of IDs may change over time.

        • container: BetaContainer

          Information about the container used in the request (for the code execution tool)

          • id: string

            Identifier for the container used in this request

          • expires_at: string

            The time at which the container will expire.

          • skills: array of BetaSkill

            Skills loaded in the container

            • skill_id: string

              Skill ID

            • type: "anthropic" or "custom"

              Type of skill - either 'anthropic' (built-in) or 'custom' (user-defined)

              • "anthropic"

              • "custom"

            • version: string

              Skill version or 'latest' for most recent version

        • content: array of BetaContentBlock

          Content generated by the model.

          This is an array of content blocks, each of which has a type that determines its shape.

          Example:

          [{"type": "text", "text": "Hi, I'm Claude."}]
          

          If the request input messages ended with an assistant turn, then the response content will continue directly from that last turn. You can use this to constrain the model's output.

          For example, if the input messages were:

          [
            {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
            {"role": "assistant", "content": "The best answer is ("}
          ]
          

          Then the response content might be:

          [{"type": "text", "text": "B)"}]
          

          • BetaTextBlock object { citations, text, type }

            • citations: array of BetaTextCitation

              Citations supporting the text block.

              The type of citation returned will depend on the type of document being cited. Citing a PDF results in page_location, plain text results in char_location, and content document results in content_block_location.

              • BetaCitationCharLocation object { cited_text, document_index, document_title, 4 more }

                • cited_text: string

                • document_index: number

                • document_title: string

                • end_char_index: number

                • file_id: string

                • start_char_index: number

                • type: "char_location"

                  • "char_location"

              • BetaCitationPageLocation object { cited_text, document_index, document_title, 4 more }

                • cited_text: string

                • document_index: number

                • document_title: string

                • end_page_number: number

                • file_id: string

                • start_page_number: number

                • type: "page_location"

                  • "page_location"

              • BetaCitationContentBlockLocation object { cited_text, document_index, document_title, 4 more }

                • cited_text: string

                  The full text of the cited block range, concatenated.

                  Always equals the contents of content[start_block_index:end_block_index] joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                • document_index: number

                • document_title: string

                • end_block_index: number

                  Exclusive 0-based end index of the cited block range in the source's content array.

                  Always greater than start_block_index; a single-block citation has end_block_index = start_block_index + 1.

                • file_id: string

                • start_block_index: number

                  0-based index of the first cited block in the source's content array.

                • type: "content_block_location"

                  • "content_block_location"

              • BetaCitationsWebSearchResultLocation object { cited_text, encrypted_index, title, 2 more }

                • cited_text: string

                • encrypted_index: string

                • title: string

                • type: "web_search_result_location"

                  • "web_search_result_location"

                • url: string

              • BetaCitationSearchResultLocation object { cited_text, end_block_index, search_result_index, 4 more }

                • cited_text: string

                  The full text of the cited block range, concatenated.

                  Always equals the contents of content[start_block_index:end_block_index] joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                • end_block_index: number

                  Exclusive 0-based end index of the cited block range in the source's content array.

                  Always greater than start_block_index; a single-block citation has end_block_index = start_block_index + 1.

                • search_result_index: number

                  0-based index of the cited search result among all search_result content blocks in the request, in the order they appear across messages and tool results.

                  Counted separately from document_index; server-side web search results are not included in this count.

                • source: string

                • start_block_index: number

                  0-based index of the first cited block in the source's content array.

                • title: string

                • type: "search_result_location"

                  • "search_result_location"

            • text: string

            • type: "text"

              • "text"

          • BetaThinkingBlock object { signature, thinking, type }

            • signature: string

            • thinking: string

            • type: "thinking"

              • "thinking"

          • BetaRedactedThinkingBlock object { data, type }

            • data: string

            • type: "redacted_thinking"

              • "redacted_thinking"

          • BetaToolUseBlock object { id, input, name, 2 more }

            • id: string

            • input: map[unknown]

            • name: string

            • type: "tool_use"

              • "tool_use"

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

                • type: "direct"

                  • "direct"

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

                • tool_id: string

                • type: "code_execution_20250825"

                  • "code_execution_20250825"

              • BetaServerToolCaller20260120 object { tool_id, type }

                • tool_id: string

                • type: "code_execution_20260120"

                  • "code_execution_20260120"

          • BetaServerToolUseBlock object { id, input, name, 2 more }

            • id: string

            • input: map[unknown]

            • name: "advisor" or "web_search" or "web_fetch" or 5 more

              • "advisor"

              • "web_search"

              • "web_fetch"

              • "code_execution"

              • "bash_code_execution"

              • "text_editor_code_execution"

              • "tool_search_tool_regex"

              • "tool_search_tool_bm25"

            • type: "server_tool_use"

              • "server_tool_use"

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaWebSearchToolResultBlock object { content, tool_use_id, type, caller }

            • content: BetaWebSearchToolResultBlockContent

              • BetaWebSearchToolResultError object { error_code, type }

                • error_code: BetaWebSearchToolResultErrorCode

                  • "invalid_tool_input"

                  • "unavailable"

                  • "max_uses_exceeded"

                  • "too_many_requests"

                  • "query_too_long"

                  • "request_too_large"

                • type: "web_search_tool_result_error"

                  • "web_search_tool_result_error"

              • array of BetaWebSearchResultBlock

                • encrypted_content: string

                • page_age: string

                • title: string

                • type: "web_search_result"

                  • "web_search_result"

                • url: string

            • tool_use_id: string

            • type: "web_search_tool_result"

              • "web_search_tool_result"

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaWebFetchToolResultBlock object { content, tool_use_id, type, caller }

            • content: BetaWebFetchToolResultErrorBlock or BetaWebFetchBlock

              • BetaWebFetchToolResultErrorBlock object { error_code, type }

                • error_code: BetaWebFetchToolResultErrorCode

                  • "invalid_tool_input"

                  • "url_too_long"

                  • "url_not_allowed"

                  • "url_not_accessible"

                  • "unsupported_content_type"

                  • "too_many_requests"

                  • "max_uses_exceeded"

                  • "unavailable"

                • type: "web_fetch_tool_result_error"

                  • "web_fetch_tool_result_error"

              • BetaWebFetchBlock object { content, retrieved_at, type, url }

                • content: BetaDocumentBlock

                  • citations: BetaCitationConfig

                    Citation configuration for the document

                    • enabled: boolean

                  • source: BetaBase64PDFSource or BetaPlainTextSource

                    • BetaBase64PDFSource object { data, media_type, type }

                      • data: string

                      • media_type: "application/pdf"

                        • "application/pdf"

                      • type: "base64"

                        • "base64"

                    • BetaPlainTextSource object { data, media_type, type }

                      • data: string

                      • media_type: "text/plain"

                        • "text/plain"

                      • type: "text"

                        • "text"

                  • title: string

                    The title of the document

                  • type: "document"

                    • "document"

                • retrieved_at: string

                  ISO 8601 timestamp when the content was retrieved

                • type: "web_fetch_result"

                  • "web_fetch_result"

                • url: string

                  Fetched content URL

            • tool_use_id: string

            • type: "web_fetch_tool_result"

              • "web_fetch_tool_result"

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaAdvisorToolResultBlock object { content, tool_use_id, type }

            • content: BetaAdvisorToolResultError or BetaAdvisorResultBlock or BetaAdvisorRedactedResultBlock

              • BetaAdvisorToolResultError object { error_code, type }

                • error_code: "max_uses_exceeded" or "prompt_too_long" or "too_many_requests" or 3 more

                  • "max_uses_exceeded"

                  • "prompt_too_long"

                  • "too_many_requests"

                  • "overloaded"

                  • "unavailable"

                  • "execution_time_exceeded"

                • type: "advisor_tool_result_error"

                  • "advisor_tool_result_error"

              • BetaAdvisorResultBlock object { text, type }

                • text: string

                • type: "advisor_result"

                  • "advisor_result"

              • BetaAdvisorRedactedResultBlock object { encrypted_content, type }

                • encrypted_content: string

                  Opaque blob containing the advisor's output. Round-trip verbatim; do not inspect or modify.

                • type: "advisor_redacted_result"

                  • "advisor_redacted_result"

            • tool_use_id: string

            • type: "advisor_tool_result"

              • "advisor_tool_result"

          • BetaCodeExecutionToolResultBlock object { content, tool_use_id, type }

            • content: BetaCodeExecutionToolResultBlockContent

              Code execution result with encrypted stdout for PFC + web_search results.

              • BetaCodeExecutionToolResultError object { error_code, type }

                • error_code: BetaCodeExecutionToolResultErrorCode

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                • type: "code_execution_tool_result_error"

                  • "code_execution_tool_result_error"

              • BetaCodeExecutionResultBlock object { content, return_code, stderr, 2 more }

                • content: array of BetaCodeExecutionOutputBlock

                  • file_id: string

                  • type: "code_execution_output"

                    • "code_execution_output"

                • return_code: number

                • stderr: string

                • stdout: string

                • type: "code_execution_result"

                  • "code_execution_result"

              • BetaEncryptedCodeExecutionResultBlock object { content, encrypted_stdout, return_code, 2 more }

                Code execution result with encrypted stdout for PFC + web_search results.

                • content: array of BetaCodeExecutionOutputBlock

                  • file_id: string

                  • type: "code_execution_output"

                • encrypted_stdout: string

                • return_code: number

                • stderr: string

                • type: "encrypted_code_execution_result"

                  • "encrypted_code_execution_result"

            • tool_use_id: string

            • type: "code_execution_tool_result"

              • "code_execution_tool_result"

          • BetaBashCodeExecutionToolResultBlock object { content, tool_use_id, type }

            • content: BetaBashCodeExecutionToolResultError or BetaBashCodeExecutionResultBlock

              • BetaBashCodeExecutionToolResultError object { error_code, type }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or 2 more

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                  • "output_file_too_large"

                • type: "bash_code_execution_tool_result_error"

                  • "bash_code_execution_tool_result_error"

              • BetaBashCodeExecutionResultBlock object { content, return_code, stderr, 2 more }

                • content: array of BetaBashCodeExecutionOutputBlock

                  • file_id: string

                  • type: "bash_code_execution_output"

                    • "bash_code_execution_output"

                • return_code: number

                • stderr: string

                • stdout: string

                • type: "bash_code_execution_result"

                  • "bash_code_execution_result"

            • tool_use_id: string

            • type: "bash_code_execution_tool_result"

              • "bash_code_execution_tool_result"

          • BetaTextEditorCodeExecutionToolResultBlock object { content, tool_use_id, type }

            • content: BetaTextEditorCodeExecutionToolResultError or BetaTextEditorCodeExecutionViewResultBlock or BetaTextEditorCodeExecutionCreateResultBlock or BetaTextEditorCodeExecutionStrReplaceResultBlock

              • BetaTextEditorCodeExecutionToolResultError object { error_code, error_message, type }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or 2 more

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                  • "file_not_found"

                • error_message: string

                • type: "text_editor_code_execution_tool_result_error"

                  • "text_editor_code_execution_tool_result_error"

              • BetaTextEditorCodeExecutionViewResultBlock object { content, file_type, num_lines, 3 more }

                • content: string

                • file_type: "text" or "image" or "pdf"

                  • "text"

                  • "image"

                  • "pdf"

                • num_lines: number

                • start_line: number

                • total_lines: number

                • type: "text_editor_code_execution_view_result"

                  • "text_editor_code_execution_view_result"

              • BetaTextEditorCodeExecutionCreateResultBlock object { is_file_update, type }

                • is_file_update: boolean

                • type: "text_editor_code_execution_create_result"

                  • "text_editor_code_execution_create_result"

              • BetaTextEditorCodeExecutionStrReplaceResultBlock object { lines, new_lines, new_start, 3 more }

                • lines: array of string

                • new_lines: number

                • new_start: number

                • old_lines: number

                • old_start: number

                • type: "text_editor_code_execution_str_replace_result"

                  • "text_editor_code_execution_str_replace_result"

            • tool_use_id: string

            • type: "text_editor_code_execution_tool_result"

              • "text_editor_code_execution_tool_result"

          • BetaToolSearchToolResultBlock object { content, tool_use_id, type }

            • content: BetaToolSearchToolResultError or BetaToolSearchToolSearchResultBlock

              • BetaToolSearchToolResultError object { error_code, error_message, type }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or "execution_time_exceeded"

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                • error_message: string

                • type: "tool_search_tool_result_error"

                  • "tool_search_tool_result_error"

              • BetaToolSearchToolSearchResultBlock object { tool_references, type }

                • tool_references: array of BetaToolReferenceBlock

                  • tool_name: string

                  • type: "tool_reference"

                    • "tool_reference"

                • type: "tool_search_tool_search_result"

                  • "tool_search_tool_search_result"

            • tool_use_id: string

            • type: "tool_search_tool_result"

              • "tool_search_tool_result"

          • BetaMCPToolUseBlock object { id, input, name, 2 more }

            • id: string

            • input: map[unknown]

            • name: string

              The name of the MCP tool

            • server_name: string

              The name of the MCP server

            • type: "mcp_tool_use"

              • "mcp_tool_use"

          • BetaMCPToolResultBlock object { content, is_error, tool_use_id, type }

            • content: string or array of BetaTextBlock

              • string

              • BetaMCPToolResultBlockContent = array of BetaTextBlock

                • citations: array of BetaTextCitation

                  Citations supporting the text block.

                  The type of citation returned will depend on the type of document being cited. Citing a PDF results in page_location, plain text results in char_location, and content document results in content_block_location.

                • text: string

                • type: "text"

            • is_error: boolean

            • tool_use_id: string

            • type: "mcp_tool_result"

              • "mcp_tool_result"

          • BetaContainerUploadBlock object { file_id, type }

            Response model for a file uploaded to the container.

            • file_id: string

            • type: "container_upload"

              • "container_upload"

          • BetaCompactionBlock object { content, encrypted_content, type }

            A compaction block returned when autocompact is triggered.

            When content is None, it indicates the compaction failed to produce a valid summary (e.g., malformed output from the model). Clients may round-trip compaction blocks with null content; the server treats them as no-ops.

            • content: string

              Summary of compacted content, or null if compaction failed

            • encrypted_content: string

              Opaque metadata from prior compaction, to be round-tripped verbatim

            • type: "compaction"

              • "compaction"

        • context_management: BetaContextManagementResponse

          Context management response.

          Information about context management strategies applied during the request.

          • applied_edits: array of BetaClearToolUses20250919EditResponse or BetaClearThinking20251015EditResponse

            List of context management edits that were applied.

            • BetaClearToolUses20250919EditResponse object { cleared_input_tokens, cleared_tool_uses, type }

              • cleared_input_tokens: number

                Number of input tokens cleared by this edit.

              • cleared_tool_uses: number

                Number of tool uses that were cleared.

              • type: "clear_tool_uses_20250919"

                The type of context management edit applied.

                • "clear_tool_uses_20250919"

            • BetaClearThinking20251015EditResponse object { cleared_input_tokens, cleared_thinking_turns, type }

              • cleared_input_tokens: number

                Number of input tokens cleared by this edit.

              • cleared_thinking_turns: number

                Number of thinking turns that were cleared.

              • type: "clear_thinking_20251015"

                The type of context management edit applied.

                • "clear_thinking_20251015"

        • diagnostics: BetaDiagnostics

          Response envelope for request-level diagnostics. Present (possibly null) whenever the caller supplied diagnostics on the request.

          • cache_miss_reason: BetaCacheMissModelChanged or BetaCacheMissSystemChanged or BetaCacheMissToolsChanged or 3 more

            Explains why the prompt cache could not fully reuse the prefix from the request identified by diagnostics.previous_message_id. null means diagnosis is still pending — the response was serialized before the background comparison completed.

            • BetaCacheMissModelChanged object { cache_missed_input_tokens, type }

              • cache_missed_input_tokens: number

                Approximate number of input tokens that would have been read from cache had the prefix matched the previous request.

              • type: "model_changed"

                • "model_changed"

            • BetaCacheMissSystemChanged object { cache_missed_input_tokens, type }

              • cache_missed_input_tokens: number

                Approximate number of input tokens that would have been read from cache had the prefix matched the previous request.

              • type: "system_changed"

                • "system_changed"

            • BetaCacheMissToolsChanged object { cache_missed_input_tokens, type }

              • cache_missed_input_tokens: number

                Approximate number of input tokens that would have been read from cache had the prefix matched the previous request.

              • type: "tools_changed"

                • "tools_changed"

            • BetaCacheMissMessagesChanged object { cache_missed_input_tokens, type }

              • cache_missed_input_tokens: number

                Approximate number of input tokens that would have been read from cache had the prefix matched the previous request.

              • type: "messages_changed"

                • "messages_changed"

            • BetaCacheMissPreviousMessageNotFound object { type }

              • type: "previous_message_not_found"

                • "previous_message_not_found"

            • BetaCacheMissUnavailable object { type }

              • type: "unavailable"

                • "unavailable"

        • model: Model

          The model that will complete your prompt.

          See models for additional details and options.

          • "claude-opus-4-7" or "claude-mythos-preview" or "claude-opus-4-6" or 14 more

            The model that will complete your prompt.

            See models for additional details and options.

            • "claude-opus-4-7"

              Frontier intelligence for long-running agents and coding

            • "claude-mythos-preview"

              New class of intelligence, strongest in coding and cybersecurity

            • "claude-opus-4-6"

              Frontier intelligence for long-running agents and coding

            • "claude-sonnet-4-6"

              Best combination of speed and intelligence

            • "claude-haiku-4-5"

              Fastest model with near-frontier intelligence

            • "claude-haiku-4-5-20251001"

              Fastest model with near-frontier intelligence

            • "claude-opus-4-5"

              Premium model combining maximum intelligence with practical performance

            • "claude-opus-4-5-20251101"

              Premium model combining maximum intelligence with practical performance

            • "claude-sonnet-4-5"

              High-performance model for agents and coding

            • "claude-sonnet-4-5-20250929"

              High-performance model for agents and coding

            • "claude-opus-4-1"

              Exceptional model for specialized complex tasks

            • "claude-opus-4-1-20250805"

              Exceptional model for specialized complex tasks

            • "claude-opus-4-0"

              Powerful model for complex tasks

            • "claude-opus-4-20250514"

              Powerful model for complex tasks

            • "claude-sonnet-4-0"

              High-performance model with extended thinking

            • "claude-sonnet-4-20250514"

              High-performance model with extended thinking

            • "claude-3-haiku-20240307"

              Fast and cost-effective model

          • string

        • role: "assistant"

          Conversational role of the generated message.

          This will always be "assistant".

          • "assistant"

        • stop_details: BetaRefusalStopDetails

          Structured information about a refusal.

          • category: "cyber" or "bio"

            The policy category that triggered the refusal.

            null when the refusal doesn't map to a named category.

            • "cyber"

            • "bio"

          • explanation: string

            Human-readable explanation of the refusal.

            This text is not guaranteed to be stable. null when no explanation is available for the category.

          • type: "refusal"

            • "refusal"

        • stop_reason: BetaStopReason

          The reason that we stopped.

          This may be one the following values:

          • "end_turn": the model reached a natural stopping point
          • "max_tokens": we exceeded the requested max_tokens or the model's maximum
          • "stop_sequence": one of your provided custom stop_sequences was generated
          • "tool_use": the model invoked one or more tools
          • "pause_turn": we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
          • "refusal": when streaming classifiers intervene to handle potential policy violations

          In non-streaming mode this value is always non-null. In streaming mode, it is null in the message_start event and non-null otherwise.

          • "end_turn"

          • "max_tokens"

          • "stop_sequence"

          • "tool_use"

          • "pause_turn"

          • "compaction"

          • "refusal"

          • "model_context_window_exceeded"

        • stop_sequence: string

          Which custom stop sequence was generated, if any.

          This value will be a non-null string if one of your custom stop sequences was generated.

        • type: "message"

          Object type.

          For Messages, this is always "message".

          • "message"

        • usage: BetaUsage

          Billing and rate-limit usage.

          Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

          Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in usage will not match one-to-one with the exact visible content of an API request or response.

          For example, output_tokens will be non-zero, even for an empty string response from Claude.

          Total input tokens in a request is the summation of input_tokens, cache_creation_input_tokens, and cache_read_input_tokens.

          • cache_creation: BetaCacheCreation

            Breakdown of cached tokens by TTL

            • ephemeral_1h_input_tokens: number

              The number of input tokens used to create the 1 hour cache entry.

            • ephemeral_5m_input_tokens: number

              The number of input tokens used to create the 5 minute cache entry.

          • cache_creation_input_tokens: number

            The number of input tokens used to create the cache entry.

          • cache_read_input_tokens: number

            The number of input tokens read from the cache.

          • inference_geo: string

            The geographic region where inference was performed for this request.

          • input_tokens: number

            The number of input tokens which were used.

          • iterations: BetaIterationsUsage

            Per-iteration token usage breakdown.

            Each entry represents one sampling iteration, with its own input/output token counts and cache statistics. This allows you to:

            • Determine which iterations exceeded long context thresholds (>=200k tokens)

            • Calculate the true context window size from the last iteration

            • Understand token accumulation across server-side tool use loops

            • BetaMessageIterationUsage object { cache_creation, cache_creation_input_tokens, cache_read_input_tokens, 3 more }

              Token usage for a sampling iteration.

              • cache_creation: BetaCacheCreation

                Breakdown of cached tokens by TTL

              • cache_creation_input_tokens: number

                The number of input tokens used to create the cache entry.

              • cache_read_input_tokens: number

                The number of input tokens read from the cache.

              • input_tokens: number

                The number of input tokens which were used.

              • output_tokens: number

                The number of output tokens which were used.

              • type: "message"

                Usage for a sampling iteration

                • "message"

            • BetaCompactionIterationUsage object { cache_creation, cache_creation_input_tokens, cache_read_input_tokens, 3 more }

              Token usage for a compaction iteration.

              • cache_creation: BetaCacheCreation

                Breakdown of cached tokens by TTL

              • cache_creation_input_tokens: number

                The number of input tokens used to create the cache entry.

              • cache_read_input_tokens: number

                The number of input tokens read from the cache.

              • input_tokens: number

                The number of input tokens which were used.

              • output_tokens: number

                The number of output tokens which were used.

              • type: "compaction"

                Usage for a compaction iteration

                • "compaction"

            • BetaAdvisorMessageIterationUsage object { cache_creation, cache_creation_input_tokens, cache_read_input_tokens, 4 more }

              Token usage for an advisor sub-inference iteration.

              • cache_creation: BetaCacheCreation

                Breakdown of cached tokens by TTL

              • cache_creation_input_tokens: number

                The number of input tokens used to create the cache entry.

              • cache_read_input_tokens: number

                The number of input tokens read from the cache.

              • input_tokens: number

                The number of input tokens which were used.

              • model: Model

                The model that will complete your prompt.

                See models for additional details and options.

              • output_tokens: number

                The number of output tokens which were used.

              • type: "advisor_message"

                Usage for an advisor sub-inference iteration

                • "advisor_message"

          • output_tokens: number

            The number of output tokens which were used.

          • server_tool_use: BetaServerToolUsage

            The number of server tool requests.

            • web_fetch_requests: number

              The number of web fetch tool requests.

            • web_search_requests: number

              The number of web search tool requests.

          • service_tier: "standard" or "priority" or "batch"

            If the request used the priority, standard, or batch tier.

            • "standard"

            • "priority"

            • "batch"

          • speed: "standard" or "fast"

            The inference speed mode used for this request.

            • "standard"

            • "fast"

      • type: "succeeded"

        • "succeeded"

    • BetaMessageBatchErroredResult object { error, type }

      • error: BetaErrorResponse

        • error: BetaError

          • BetaInvalidRequestError object { message, type }

            • message: string

            • type: "invalid_request_error"

              • "invalid_request_error"

          • BetaAuthenticationError object { message, type }

            • message: string

            • type: "authentication_error"

              • "authentication_error"

          • BetaBillingError object { message, type }

            • message: string

            • type: "billing_error"

              • "billing_error"

          • BetaPermissionError object { message, type }

            • message: string

            • type: "permission_error"

              • "permission_error"

          • BetaNotFoundError object { message, type }

            • message: string

            • type: "not_found_error"

              • "not_found_error"

          • BetaRateLimitError object { message, type }

            • message: string

            • type: "rate_limit_error"

              • "rate_limit_error"

          • BetaGatewayTimeoutError object { message, type }

            • message: string

            • type: "timeout_error"

              • "timeout_error"

          • BetaAPIError object { message, type }

            • message: string

            • type: "api_error"

              • "api_error"

          • BetaOverloadedError object { message, type }

            • message: string

            • type: "overloaded_error"

              • "overloaded_error"

        • request_id: string

        • type: "error"

          • "error"

      • type: "errored"

        • "errored"

    • BetaMessageBatchCanceledResult object { type }

      • type: "canceled"

        • "canceled"

    • BetaMessageBatchExpiredResult object { type }

      • type: "expired"

        • "expired"

Example

curl https://api.anthropic.com/v1/messages/batches/$MESSAGE_BATCH_ID/results \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: message-batches-2024-09-24' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY"

Domain Types

Beta Deleted Message Batch

• BetaDeletedMessageBatch object { id, type }

  • id: string

    ID of the Message Batch.

  • type: "message_batch_deleted"

    Deleted object type.

    For Message Batches, this is always "message_batch_deleted".

    • "message_batch_deleted"

Beta Message Batch

• BetaMessageBatch object { id, archived_at, cancel_initiated_at, 7 more }

  • id: string

    Unique object identifier.

    The format and length of IDs may change over time.

  • archived_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  • cancel_initiated_at: string

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  • created_at: string

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  • ended_at: string

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  • expires_at: string

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  • processing_status: "in_progress" or "canceling" or "ended"

    Processing status of the Message Batch.

    • "in_progress"

    • "canceling"

    • "ended"

  • request_counts: BetaMessageBatchRequestCounts

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as processing and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    • canceled: number

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    • errored: number

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    • expired: number

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    • processing: number

      Number of requests in the Message Batch that are processing.

    • succeeded: number

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  • results_url: string

    URL to a .jsonl file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the custom_id field to match results to requests.

  • type: "message_batch"

    Object type.

    For Message Batches, this is always "message_batch".

    • "message_batch"

Beta Message Batch Canceled Result

• BetaMessageBatchCanceledResult object { type }

  • type: "canceled"

    • "canceled"

Beta Message Batch Errored Result

• BetaMessageBatchErroredResult object { error, type }

  • error: BetaErrorResponse

    • error: BetaError

      • BetaInvalidRequestError object { message, type }

        • message: string

        • type: "invalid_request_error"

          • "invalid_request_error"

      • BetaAuthenticationError object { message, type }

        • message: string

        • type: "authentication_error"

          • "authentication_error"

      • BetaBillingError object { message, type }

        • message: string

        • type: "billing_error"

          • "billing_error"

      • BetaPermissionError object { message, type }

        • message: string

        • type: "permission_error"

          • "permission_error"

      • BetaNotFoundError object { message, type }

        • message: string

        • type: "not_found_error"

          • "not_found_error"

      • BetaRateLimitError object { message, type }

        • message: string

        • type: "rate_limit_error"

          • "rate_limit_error"

      • BetaGatewayTimeoutError object { message, type }

        • message: string

        • type: "timeout_error"

          • "timeout_error"

      • BetaAPIError object { message, type }

        • message: string

        • type: "api_error"

          • "api_error"

      • BetaOverloadedError object { message, type }

        • message: string

        • type: "overloaded_error"

          • "overloaded_error"

    • request_id: string

    • type: "error"

      • "error"

  • type: "errored"

    • "errored"

Beta Message Batch Expired Result

• BetaMessageBatchExpiredResult object { type }

  • type: "expired"

    • "expired"

Beta Message Batch Individual Response

• BetaMessageBatchIndividualResponse object { custom_id, result }

  This is a single line in the response .jsonl file and does not represent the response as a whole.

  • custom_id: string

    Developer-provided ID created for each request in a Message Batch. Useful for matching results to requests, as results may be given out of request order.

    Must be unique for each request within the Message Batch.

  • result: BetaMessageBatchResult

    Processing result for this request.

    Contains a Message output if processing was successful, an error response if processing failed, or the reason why processing was not attempted, such as cancellation or expiration.

    • BetaMessageBatchSucceededResult object { message, type }

      • message: BetaMessage

        • id: string

          Unique object identifier.

          The format and length of IDs may change over time.

        • container: BetaContainer

          Information about the container used in the request (for the code execution tool)

          • id: string

            Identifier for the container used in this request

          • expires_at: string

            The time at which the container will expire.

          • skills: array of BetaSkill

            Skills loaded in the container

            • skill_id: string

              Skill ID

            • type: "anthropic" or "custom"

              Type of skill - either 'anthropic' (built-in) or 'custom' (user-defined)

              • "anthropic"

              • "custom"

            • version: string

              Skill version or 'latest' for most recent version

        • content: array of BetaContentBlock

          Content generated by the model.

          This is an array of content blocks, each of which has a type that determines its shape.

          Example:

          [{"type": "text", "text": "Hi, I'm Claude."}]
          

          If the request input messages ended with an assistant turn, then the response content will continue directly from that last turn. You can use this to constrain the model's output.

          For example, if the input messages were:

          [
            {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
            {"role": "assistant", "content": "The best answer is ("}
          ]
          

          Then the response content might be:

          [{"type": "text", "text": "B)"}]
          

          • BetaTextBlock object { citations, text, type }

            • citations: array of BetaTextCitation

              Citations supporting the text block.

              The type of citation returned will depend on the type of document being cited. Citing a PDF results in page_location, plain text results in char_location, and content document results in content_block_location.

              • BetaCitationCharLocation object { cited_text, document_index, document_title, 4 more }

                • cited_text: string

                • document_index: number

                • document_title: string

                • end_char_index: number

                • file_id: string

                • start_char_index: number

                • type: "char_location"

                  • "char_location"

              • BetaCitationPageLocation object { cited_text, document_index, document_title, 4 more }

                • cited_text: string

                • document_index: number

                • document_title: string

                • end_page_number: number

                • file_id: string

                • start_page_number: number

                • type: "page_location"

                  • "page_location"

              • BetaCitationContentBlockLocation object { cited_text, document_index, document_title, 4 more }

                • cited_text: string

                  The full text of the cited block range, concatenated.

                  Always equals the contents of content[start_block_index:end_block_index] joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                • document_index: number

                • document_title: string

                • end_block_index: number

                  Exclusive 0-based end index of the cited block range in the source's content array.

                  Always greater than start_block_index; a single-block citation has end_block_index = start_block_index + 1.

                • file_id: string

                • start_block_index: number

                  0-based index of the first cited block in the source's content array.

                • type: "content_block_location"

                  • "content_block_location"

              • BetaCitationsWebSearchResultLocation object { cited_text, encrypted_index, title, 2 more }

                • cited_text: string

                • encrypted_index: string

                • title: string

                • type: "web_search_result_location"

                  • "web_search_result_location"

                • url: string

              • BetaCitationSearchResultLocation object { cited_text, end_block_index, search_result_index, 4 more }

                • cited_text: string

                  The full text of the cited block range, concatenated.

                  Always equals the contents of content[start_block_index:end_block_index] joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                • end_block_index: number

                  Exclusive 0-based end index of the cited block range in the source's content array.

                  Always greater than start_block_index; a single-block citation has end_block_index = start_block_index + 1.

                • search_result_index: number

                  0-based index of the cited search result among all search_result content blocks in the request, in the order they appear across messages and tool results.

                  Counted separately from document_index; server-side web search results are not included in this count.

                • source: string

                • start_block_index: number

                  0-based index of the first cited block in the source's content array.

                • title: string

                • type: "search_result_location"

                  • "search_result_location"

            • text: string

            • type: "text"

              • "text"

          • BetaThinkingBlock object { signature, thinking, type }

            • signature: string

            • thinking: string

            • type: "thinking"

              • "thinking"

          • BetaRedactedThinkingBlock object { data, type }

            • data: string

            • type: "redacted_thinking"

              • "redacted_thinking"

          • BetaToolUseBlock object { id, input, name, 2 more }

            • id: string

            • input: map[unknown]

            • name: string

            • type: "tool_use"

              • "tool_use"

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

                • type: "direct"

                  • "direct"

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

                • tool_id: string

                • type: "code_execution_20250825"

                  • "code_execution_20250825"

              • BetaServerToolCaller20260120 object { tool_id, type }

                • tool_id: string

                • type: "code_execution_20260120"

                  • "code_execution_20260120"

          • BetaServerToolUseBlock object { id, input, name, 2 more }

            • id: string

            • input: map[unknown]

            • name: "advisor" or "web_search" or "web_fetch" or 5 more

              • "advisor"

              • "web_search"

              • "web_fetch"

              • "code_execution"

              • "bash_code_execution"

              • "text_editor_code_execution"

              • "tool_search_tool_regex"

              • "tool_search_tool_bm25"

            • type: "server_tool_use"

              • "server_tool_use"

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaWebSearchToolResultBlock object { content, tool_use_id, type, caller }

            • content: BetaWebSearchToolResultBlockContent

              • BetaWebSearchToolResultError object { error_code, type }

                • error_code: BetaWebSearchToolResultErrorCode

                  • "invalid_tool_input"

                  • "unavailable"

                  • "max_uses_exceeded"

                  • "too_many_requests"

                  • "query_too_long"

                  • "request_too_large"

                • type: "web_search_tool_result_error"

                  • "web_search_tool_result_error"

              • array of BetaWebSearchResultBlock

                • encrypted_content: string

                • page_age: string

                • title: string

                • type: "web_search_result"

                  • "web_search_result"

                • url: string

            • tool_use_id: string

            • type: "web_search_tool_result"

              • "web_search_tool_result"

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaWebFetchToolResultBlock object { content, tool_use_id, type, caller }

            • content: BetaWebFetchToolResultErrorBlock or BetaWebFetchBlock

              • BetaWebFetchToolResultErrorBlock object { error_code, type }

                • error_code: BetaWebFetchToolResultErrorCode

                  • "invalid_tool_input"

                  • "url_too_long"

                  • "url_not_allowed"

                  • "url_not_accessible"

                  • "unsupported_content_type"

                  • "too_many_requests"

                  • "max_uses_exceeded"

                  • "unavailable"

                • type: "web_fetch_tool_result_error"

                  • "web_fetch_tool_result_error"

              • BetaWebFetchBlock object { content, retrieved_at, type, url }

                • content: BetaDocumentBlock

                  • citations: BetaCitationConfig

                    Citation configuration for the document

                    • enabled: boolean

                  • source: BetaBase64PDFSource or BetaPlainTextSource

                    • BetaBase64PDFSource object { data, media_type, type }

                      • data: string

                      • media_type: "application/pdf"

                        • "application/pdf"

                      • type: "base64"

                        • "base64"

                    • BetaPlainTextSource object { data, media_type, type }

                      • data: string

                      • media_type: "text/plain"

                        • "text/plain"

                      • type: "text"

                        • "text"

                  • title: string

                    The title of the document

                  • type: "document"

                    • "document"

                • retrieved_at: string

                  ISO 8601 timestamp when the content was retrieved

                • type: "web_fetch_result"

                  • "web_fetch_result"

                • url: string

                  Fetched content URL

            • tool_use_id: string

            • type: "web_fetch_tool_result"

              • "web_fetch_tool_result"

            • caller: optional BetaDirectCaller or BetaServerToolCaller or BetaServerToolCaller20260120

              Tool invocation directly from the model.

              • BetaDirectCaller object { type }

                Tool invocation directly from the model.

              • BetaServerToolCaller object { tool_id, type }

                Tool invocation generated by a server-side tool.

              • BetaServerToolCaller20260120 object { tool_id, type }

          • BetaAdvisorToolResultBlock object { content, tool_use_id, type }

            • content: BetaAdvisorToolResultError or BetaAdvisorResultBlock or BetaAdvisorRedactedResultBlock

              • BetaAdvisorToolResultError object { error_code, type }

                • error_code: "max_uses_exceeded" or "prompt_too_long" or "too_many_requests" or 3 more

                  • "max_uses_exceeded"

                  • "prompt_too_long"

                  • "too_many_requests"

                  • "overloaded"

                  • "unavailable"

                  • "execution_time_exceeded"

                • type: "advisor_tool_result_error"

                  • "advisor_tool_result_error"

              • BetaAdvisorResultBlock object { text, type }

                • text: string

                • type: "advisor_result"

                  • "advisor_result"

              • BetaAdvisorRedactedResultBlock object { encrypted_content, type }

                • encrypted_content: string

                  Opaque blob containing the advisor's output. Round-trip verbatim; do not inspect or modify.

                • type: "advisor_redacted_result"

                  • "advisor_redacted_result"

            • tool_use_id: string

            • type: "advisor_tool_result"

              • "advisor_tool_result"

          • BetaCodeExecutionToolResultBlock object { content, tool_use_id, type }

            • content: BetaCodeExecutionToolResultBlockContent

              Code execution result with encrypted stdout for PFC + web_search results.

              • BetaCodeExecutionToolResultError object { error_code, type }

                • error_code: BetaCodeExecutionToolResultErrorCode

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                • type: "code_execution_tool_result_error"

                  • "code_execution_tool_result_error"

              • BetaCodeExecutionResultBlock object { content, return_code, stderr, 2 more }

                • content: array of BetaCodeExecutionOutputBlock

                  • file_id: string

                  • type: "code_execution_output"

                    • "code_execution_output"

                • return_code: number

                • stderr: string

                • stdout: string

                • type: "code_execution_result"

                  • "code_execution_result"

              • BetaEncryptedCodeExecutionResultBlock object { content, encrypted_stdout, return_code, 2 more }

                Code execution result with encrypted stdout for PFC + web_search results.

                • content: array of BetaCodeExecutionOutputBlock

                  • file_id: string

                  • type: "code_execution_output"

                • encrypted_stdout: string

                • return_code: number

                • stderr: string

                • type: "encrypted_code_execution_result"

                  • "encrypted_code_execution_result"

            • tool_use_id: string

            • type: "code_execution_tool_result"

              • "code_execution_tool_result"

          • BetaBashCodeExecutionToolResultBlock object { content, tool_use_id, type }

            • content: BetaBashCodeExecutionToolResultError or BetaBashCodeExecutionResultBlock

              • BetaBashCodeExecutionToolResultError object { error_code, type }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or 2 more

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                  • "output_file_too_large"

                • type: "bash_code_execution_tool_result_error"

                  • "bash_code_execution_tool_result_error"

              • BetaBashCodeExecutionResultBlock object { content, return_code, stderr, 2 more }

                • content: array of BetaBashCodeExecutionOutputBlock

                  • file_id: string

                  • type: "bash_code_execution_output"

                    • "bash_code_execution_output"

                • return_code: number

                • stderr: string

                • stdout: string

                • type: "bash_code_execution_result"

                  • "bash_code_execution_result"

            • tool_use_id: string

            • type: "bash_code_execution_tool_result"

              • "bash_code_execution_tool_result"

          • BetaTextEditorCodeExecutionToolResultBlock object { content, tool_use_id, type }

            • content: BetaTextEditorCodeExecutionToolResultError or BetaTextEditorCodeExecutionViewResultBlock or BetaTextEditorCodeExecutionCreateResultBlock or BetaTextEditorCodeExecutionStrReplaceResultBlock

              • BetaTextEditorCodeExecutionToolResultError object { error_code, error_message, type }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or 2 more

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                  • "file_not_found"

                • error_message: string

                • type: "text_editor_code_execution_tool_result_error"

                  • "text_editor_code_execution_tool_result_error"

              • BetaTextEditorCodeExecutionViewResultBlock object { content, file_type, num_lines, 3 more }

                • content: string

                • file_type: "text" or "image" or "pdf"

                  • "text"

                  • "image"

                  • "pdf"

                • num_lines: number

                • start_line: number

                • total_lines: number

                • type: "text_editor_code_execution_view_result"

                  • "text_editor_code_execution_view_result"

              • BetaTextEditorCodeExecutionCreateResultBlock object { is_file_update, type }

                • is_file_update: boolean

                • type: "text_editor_code_execution_create_result"

                  • "text_editor_code_execution_create_result"

              • BetaTextEditorCodeExecutionStrReplaceResultBlock object { lines, new_lines, new_start, 3 more }

                • lines: array of string

                • new_lines: number

                • new_start: number

                • old_lines: number

                • old_start: number

                • type: "text_editor_code_execution_str_replace_result"

                  • "text_editor_code_execution_str_replace_result"

            • tool_use_id: string

            • type: "text_editor_code_execution_tool_result"

              • "text_editor_code_execution_tool_result"

          • BetaToolSearchToolResultBlock object { content, tool_use_id, type }

            • content: BetaToolSearchToolResultError or BetaToolSearchToolSearchResultBlock

              • BetaToolSearchToolResultError object { error_code, error_message, type }

                • error_code: "invalid_tool_input" or "unavailable" or "too_many_requests" or "execution_time_exceeded"

                  • "invalid_tool_input"

                  • "unavailable"

                  • "too_many_requests"

                  • "execution_time_exceeded"

                • error_message: string

                • type: "tool_search_tool_result_error"

                  • "tool_search_tool_result_error"

              • BetaToolSearchToolSearchResultBlock object { tool_references, type }

                • tool_references: array of BetaToolReferenceBlock

                  • tool_name: string

                  • type: "tool_reference"

                    • "tool_reference"

                • type: "tool_search_tool_search_result"

                  • "tool_search_tool_search_result"

            • tool_use_id: string

            • type: "tool_search_tool_result"

              • "tool_search_tool_result"

          • BetaMCPToolUseBlock object { id, input, name, 2 more }

            • id: string

            • input: map[unknown]

            • name: string

              The name of the MCP tool

            • server_name: string

              The name of the MCP server

            • type: "mcp_tool_use"

              • "mcp_tool_use"

          • BetaMCPToolResultBlock object { content, is_error, tool_use_id, type }

            • content: string or array of BetaTextBlock

              • string

              • BetaMCPToolResultBlockContent = array of BetaTextBlock

                • citations: array of BetaTextCitation

                  Citations supporting the text block.

                  The type of citation returned will depend on the type of document being cited. Citing a PDF results in page_location, plain text results in char_location, and content document results in content_block_location.

                • text: string

                • type: "text"

            • is_error: boolean

            • tool_use_id: string

            • type: "mcp_tool_result"

              • "mcp_tool_result"

          • BetaContainerUploadBlock object { file_id, type }

            Response model for a file uploaded to the container.

            • file_id: string

            • type: "container_upload"

              • "container_upload"

          • BetaCompactionBlock object { content, encrypted_content, type }

            A compaction block returned when autocompact is triggered.

            When content is None, it indicates the compaction failed to produce a valid summary (e.g., malformed output from the model). Clients may round-trip compaction blocks with null content; the server treats them as no-ops.

            • content: string

              Summary of compacted content, or null if compaction failed

            • encrypted_content: string

              Opaque metadata from prior compaction, to be round-tripped verbatim

            • type: "compaction"

              • "compaction"

        • context_management: BetaContextManagementResponse

          Context management response.

          Information about context management strategies applied during the request.

          • applied_edits: array of BetaClearToolUses20250919EditResponse or BetaClearThinking20251015EditResponse

            List of context management edits that were applied.

            • BetaClearToolUses20250919EditResponse object { cleared_input_tokens, cleared_tool_uses, type }

              • cleared_input_tokens: number

                Number of input tokens cleared by this edit.

              • cleared_tool_uses: number

                Number of tool uses that were cleared.

              • type: "clear_tool_uses_20250919"

                The type of context management edit applied.

                • "clear_tool_uses_20250919"

            • BetaClearThinking20251015EditResponse object { cleared_input_tokens, cleared_thinking_turns, type }

              • cleared_input_tokens: number

                Number of input tokens cleared by this edit.

              • cleared_thinking_turns: number

                Number of thinking turns that were cleared.

              • type: "clear_thinking_20251015"

                The type of context management edit applied.

                • "clear_thinking_20251015"

        • diagnostics: BetaDiagnostics

          Response envelope for request-level diagnostics. Present (possibly null) whenever the caller supplied diagnostics on the request.

          • cache_miss_reason: BetaCacheMissModelChanged or BetaCacheMissSystemChanged or BetaCacheMissToolsChanged or 3 more

            Explains why the prompt cache could not fully reuse the prefix from the request identified by diagnostics.previous_message_id. null means diagnosis is still pending — the response was serialized before the background comparison completed.

            • BetaCacheMissModelChanged object { cache_missed_input_tokens, type }

              • cache_missed_input_tokens: number

                Approximate number of input tokens that would have been read from cache had the prefix matched the previous request.

              • type: "model_changed"

                • "model_changed"

            • BetaCacheMissSystemChanged object { cache_missed_input_tokens, type }

              • cache_missed_input_tokens: number

                Approximate number of input tokens that would have been read from cache had the prefix matched the previous request.

              • type: "system_changed"

                • "system_changed"

            • BetaCacheMissToolsChanged object { cache_missed_input_tokens, type }

              • cache_missed_input_tokens: number

                Approximate number of input tokens that would have been read from cache had the prefix matched the previous request.

              • type: "tools_changed"

                • "tools_changed"

            • BetaCacheMissMessagesChanged object { cache_missed_input_tokens, type }

              • cache_missed_input_tokens: number

                Approximate number of input tokens that would have been read from cache had the prefix matched the previous request.

              • type: "messages_changed"

                • "messages_changed"

            • BetaCacheMissPreviousMessageNotFound object { type }

              • type: "previous_message_not_found"

                • "previous_message_not_found"

            • BetaCacheMissUnavailable object { type }

              • type: "unavailable"

                • "unavailable"

        • model: Model

          The model that will complete your prompt.

          See models for additional details and options.

          • "claude-opus-4-7" or "claude-mythos-preview" or "claude-opus-4-6" or 14 more

            The model that will complete your prompt.

            See models for additional details and options.

            • "claude-opus-4-7"

              Frontier intelligence for long-running agents and coding

            • "claude-mythos-preview"

              New class of intelligence, strongest in coding and cybersecurity

            • "claude-opus-4-6"

              Frontier intelligence for long-running agents and coding

            • "claude-sonnet-4-6"

              Best combination of speed and intelligence

            • "claude-haiku-4-5"

              Fastest model with near-frontier intelligence

            • "claude-haiku-4-5-20251001"

              Fastest model with near-frontier intelligence

            • "claude-opus-4-5"

              Premium model combining maximum intelligence with practical performance

            • "claude-opus-4-5-20251101"

              Premium model combining maximum intelligence with practical performance

            • "claude-sonnet-4-5"

              High-performance model for agents and coding

            • "claude-sonnet-4-5-20250929"

              High-performance model for agents and coding

            • "claude-opus-4-1"

              Exceptional model for specialized complex tasks

            • "claude-opus-4-1-20250805"

              Exceptional model for specialized complex tasks

            • "claude-opus-4-0"

              Powerful model for complex tasks

            • "claude-opus-4-20250514"

              Powerful model for complex tasks

            • "claude-sonnet-4-0"

              High-performance model with extended thinking

            • "claude-sonnet-4-20250514"

              High-performance model with extended thinking

            • "claude-3-haiku-20240307"

              Fast and cost-effective model

          • string

        • role: "assistant"

          Conversational role of the generated message.

          This will always be "assistant".

          • "assistant"

        • stop_details: BetaRefusalStopDetails

          Structured information about a refusal.

          • category: "cyber" or "bio"

            The policy category that triggered the refusal.

            null when the refusal doesn't map to a named category.

            • "cyber"

            • "bio"

          • explanation: string

            Human-readable explanation of the refusal.

            This text is not guaranteed to be stable. null when no explanation is available for the category.

          • type: "refusal"

            • "refusal"

        • stop_reason: BetaStopReason

          The reason that we stopped.

          This may be one the following values:

          • "end_turn": the model reached a natural stopping point
          • "max_tokens": we exceeded the requested max_tokens or the model's maximum
          • "stop_sequence": one of your provided custom stop_sequences was generated
          • "tool_use": the model invoked one or more tools
          • "pause_turn": we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
          • "refusal": when streaming classifiers intervene to handle potential policy violations

          In non-streaming mode this value is always non-null. In streaming mode, it is null in the message_start event and non-null otherwise.

          • "end_turn"

          • "max_tokens"

          • "stop_sequence"

          • "tool_use"

          • "pause_turn"

          • "compaction"

          • "refusal"

          • "model_context_window_exceeded"

        • stop_sequence: string

          Which custom stop sequence was generated, if any.

          This value will be a non-null string if one of your custom stop sequences was generated.

        • type: "message"

          Object type.

          For Messages, this is always "message".

          • "message"

        • usage: BetaUsage

          Billing and rate-limit usage.

          Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

          Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in usage will not match one-to-one with the exact visible content of an API request or response.

          For example, output_tokens will be non-zero, even for an empty string response from Claude.

          Total input tokens in a request is the summation of input_tokens, cache_creation_input_tokens, and cache_read_input_tokens.

          • cache_creation: BetaCacheCreation

            Breakdown of cached tokens by TTL

            • ephemeral_1h_input_tokens: number

              The number of input tokens used to create the 1 hour cache entry.

            • ephemeral_5m_input_tokens: number

              The number of input tokens used to create the 5 minute cache entry.

          • cache_creation_input_tokens: number

            The number of input tokens used to create the cache entry.

          • cache_read_input_tokens: number

            The number of input tokens read from the cache.

          • inference_geo: string

            The geographic region where inference was performed for this request.

          • input_tokens: number

            The number of input tokens which were used.

          • iterations: BetaIterationsUsage

            Per-iteration token usage breakdown.

            Each entry represents one sampling iteration, with its own input/output token counts and cache statistics. This allows you to:

            • Determine which iterations exceeded long context thresholds (>=200k tokens)

            • Calculate the true context window size from the last iteration

            • Understand token accumulation across server-side tool use loops

            • BetaMessageIterationUsage object { cache_creation, cache_creation_input_tokens, cache_read_input_tokens, 3 more }

              Token usage for a sampling iteration.

              • cache_creation: BetaCacheCreation

                Breakdown of cached tokens by TTL

              • cache_creation_input_tokens: number

                The number of input tokens used to create the cache entry.

              • cache_read_input_tokens: number

                The number of input tokens read from the cache.

              • input_tokens: number

                The number of input tokens which were used.

              • output_tokens: number

                The number of output tokens which were used.

              • type: "message"

                Usage for a sampling iteration

                • "message"

            • BetaCompactionIterationUsage object { cache_creation, cache_creation_input_tokens, cache_read_input_tokens, 3 more }

              Token usage for a compaction iteration.

              • cache_creation: BetaCacheCreation

                Breakdown of cached tokens by TTL

              • cache_creation_input_tokens: number

                The number of input tokens used to create the cache entry.

              • cache_read_input_tokens: number

                The number of input tokens read from the cache.

              • input_tokens: number

                The number of input tokens which were used.

              • output_tokens: number

                The number of output tokens which were used.

              • type: "compaction"

                Usage for a compaction iteration

                • "compaction"

            • BetaAdvisorMessageIterationUsage object { cache_creation, cache_creation_input_tokens, cache_read_input_tokens, 4 more }

              Token usage for an advisor sub-inference iteration.

              • cache_creation: BetaCacheCreation

                Breakdown of cached tokens by TTL

              • cache_creation_input_tokens: number

                The number of input tokens used to create the cache entry.

              • cache_read_input_tokens: number

                The number of input tokens read from the cache.

              • input_tokens: number

                The number of input tokens which were used.

              • model: Model

                The model that will complete your prompt.

                See models for additional details and options.

              • output_tokens: number

                The number of output tokens which were used.

              • type: "advisor_message"

                Usage for an advisor sub-inference iteration

                • "advisor_message"

          • output_tokens: number

            The number of output tokens which were used.

          • server_tool_use: BetaServerToolUsage

            The number of server tool requests.

            • web_fetch_requests: number

              The number of web fetch tool requests.

            • web_search_requests: number

              The number of web search tool requests.

          • service_tier: "standard" or "priority" or "batch"

            If the request used the priority, standard, or batch tier.

            • "standard"

            • "priority"

            • "batch"

          • speed: "standard" or "fast"

            The inference speed mode used for this request.

            • "standard"

            • "fast"

      • type: "succeeded"

        • "succeeded"

    • BetaMessageBatchErroredResult object { error, type }

      • error: BetaErrorResponse

        • error: BetaError

          • BetaInvalidRequestError object { message, type }

            • message: string

            • type: "invalid_request_error"

              • "invalid_request_error"

          • BetaAuthenticationError object { message, type }

            • message: string

            • type: "authentication_error"

              • "authentication_error"

          • BetaBillingError object { message, type }

            • message: string

            • type: "billing_error"

              • "billing_error"

          • BetaPermissionError object { message, type }

            • message: string

            • type: "permission_error"

              • "permission_error"

          • BetaNotFoundError object { message, type }

            • message: string

            • type: "not_found_error"

              • "not_found_error"

          • BetaRateLimitError object { message, type }

            • message: string

            • type: "rate_limit_error"

              • "rate_limit_error"

          • BetaGatewayTimeoutError object { message, type }

            • message: string

            • type: "timeout_error"

              • "timeout_error"

          • BetaAPIError object { message, type }

            • message: string

            • type: "api_error"

              • "api_error"

          • BetaOverloadedError object { message, type }

            • message: string

            • type: "overloaded_error"

              • "overloaded_error"

        • request_id: string

        • type: "error"

          • "error"

      • type: "errored"

        • "errored"

    • BetaMessageBatchCanceledResult object { type }

      • type: "canceled"

        • "canceled"

    • BetaMessageBatchExpiredResult object { type }

      • type: "expired"

        • "expired"