Completions
Create a Text Completion
post /v1/complete
[Legacy] Create a Text Completion.
The Text Completions API is a legacy API. We recommend using the Messages API going forward.
Future models and features will not be compatible with Text Completions. See our migration guide for guidance in migrating from Text Completions to Messages.
Header Parameters
-
"anthropic-beta": optional array of AnthropicBetaOptional 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
-
max_tokens_to_sample: numberThe 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.
-
model: ModelThe 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 moreThe 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
-
-
prompt: stringThe prompt that you want Claude to complete.
For proper response generation you will need to format your prompt using alternating `
Human:
andAssistant:` conversational turns. For example:
" Human: {userQuestion} Assistant:"See prompt validation and our guide to prompt design for more details.
-
metadata: optional MetadataAn object describing metadata about the request.
-
user_id: optional stringAn 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.
-
-
stop_sequences: optional array of stringSequences that will cause the model to stop generating.
Our models stop on `"
Human:"`, and may include additional built-in stop sequences in the future. By providing the stop_sequences parameter, you may include additional strings that will cause the model to stop generating.
-
stream: optional booleanWhether to incrementally stream the response using server-sent events.
See streaming for details.
-
temperature: optional numberAmount of randomness injected into the response.
Defaults to
1.0. Ranges from0.0to1.0. Usetemperaturecloser to0.0for analytical / multiple choice, and closer to1.0for creative and generative tasks.Note that even with
temperatureof0.0, the results will not be fully deterministic. -
top_k: optional numberOnly 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 numberUse 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.
Returns
-
Completion object { id, completion, model, 2 more }-
id: stringUnique object identifier.
The format and length of IDs may change over time.
-
completion: stringThe resulting completion up to and excluding the stop sequences.
-
model: ModelThe 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 moreThe 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
-
-
stop_reason: stringThe reason that we stopped.
This may be one the following values:
"stop_sequence": we reached a stop sequence — either provided by you via thestop_sequencesparameter, or a stop sequence built into the model"max_tokens": we exceededmax_tokens_to_sampleor the model's maximum
-
type: "completion"Object type.
For Text Completions, this is always
"completion"."completion"
-
Example
curl https://api.anthropic.com/v1/complete \
-H 'Content-Type: application/json' \
-H 'anthropic-version: 2023-06-01' \
-H "X-Api-Key: $ANTHROPIC_API_KEY" \
--max-time 600 \
-d '{
"max_tokens_to_sample": 256,
"model": "claude-2.1",
"prompt": "\\n\\nHuman: Hello, world!\\n\\nAssistant:",
"temperature": 1,
"top_k": 5,
"top_p": 0.7
}'
Response
{
"id": "compl_018CKm6gsux7P8yMcwZbeCPw",
"completion": " Hello! My name is Claude.",
"model": "claude-2.1",
"stop_reason": "stop_sequence",
"type": "completion"
}
Domain Types
Completion
-
Completion object { id, completion, model, 2 more }-
id: stringUnique object identifier.
The format and length of IDs may change over time.
-
completion: stringThe resulting completion up to and excluding the stop sequences.
-
model: ModelThe 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 moreThe 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
-
-
stop_reason: stringThe reason that we stopped.
This may be one the following values:
"stop_sequence": we reached a stop sequence — either provided by you via thestop_sequencesparameter, or a stop sequence built into the model"max_tokens": we exceededmax_tokens_to_sampleor the model's maximum
-
type: "completion"Object type.
For Text Completions, this is always
"completion"."completion"
-