Update chat completion

POST https://api.fastapi.ai/v1/chat/completions/{completion_id}

Modify a stored chat completion. Only chat completions that have been created with the store parameter set to true can be modified. Currently, the only supported modification is to update the metadata field.

Path parameters

completion_id string Required
The ID of the chat completion to update.

Request body

metadata map string Required
Set of 16 key-value pairs that can be attached to an object. This can be useful for storing additional information about the object in a structured format, and querying for objects via API or the dashboard.

Keys are strings with a maximum length of 64 characters. Values are strings with a maximum length of 512 characters.

Returns

The ChatCompletion object matching the specified ID.

The chat completion object

Represents a chat completion response returned by model, based on the provided input.

id string
A unique identifier for the chat completion.

choices array

A list of chat completion choices. Can be more than one if n is greater than 1.

finish_reason string
The reason the model stopped generating tokens. This will be stop if the model hit a natural stop point or a provided stop sequence, length if the maximum number of tokens specified in the request was reached, content_filter if content was omitted due to a flag from our content filters, tool_calls if the model called a tool, or function_call (deprecated) if the model called a function.

index integer
The index of the choice in the list of choices.

message object
A chat completion message generated by the model.

content string or null
The contents of the message.

refusal string or null
The refusal message generated by the model.

tool_calls array
The tool calls generated by the model, such as function calls.

id string
The ID of the tool call.

type string
The type of the tool. Currently, only function is supported.

function object
The function that the model called.

name string
The name of the function to call.

arguments string
The arguments to call the function with, as generated by the model in JSON format. Note that the model does not always generate valid JSON, and may hallucinate parameters not defined by your function schema. Validate the arguments in your code before calling your function.

role string
The role of the author of this message.

function_call Deprecated object
Deprecated and replaced by tool_calls. The name and arguments of a function that should be called, as generated by the model.

arguments string
The arguments to call the function with, as generated by the model in JSON format. Note that the model does not always generate valid JSON, and may hallucinate parameters not defined by your function schema. Validate the arguments in your code before calling your function.

name string
The name of the function to call.

audio object or null
If the audio output modality is requested, this object contains data about the audio response from the model. Learn more.

id string
Unique identifier for this audio response.

expires_at integer
The Unix timestamp (in seconds) for when this audio response will no longer be accessible on the server for use in multi-turn conversations.

data string
Base64 encoded audio bytes generated by the model, in the format specified in the request.

transcript string
Transcript of the audio generated by the model.

id string
The identifier of the chat message.

logprobs object or null
Log probability information for the choice.

content array or null
A list of message content tokens with log probability information.

token string
The token.

logprob number
The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

bytes array or null
A list of integers representing the UTF-8 bytes representation of the token. Useful in instances where characters are represented by multiple tokens and their byte representations must be combined to generate the correct text representation. Can be null if there is no bytes representation for the token.

top_logprobs array
List of the most likely tokens and their log probability, at this token position. In rare cases, there may be fewer than the number of requested top_logprobs returned.

token string
The token.

logprob number
The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

bytes array or null
A list of integers representing the UTF-8 bytes representation of the token. Useful in instances where characters are represented by multiple tokens and their byte representations must be combined to generate the correct text representation. Can be null if there is no bytes representation for the token.

refusal array or null
A list of message refusal tokens with log probability information.

token string
The token.

logprob number
The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

bytes array or null
A list of integers representing the UTF-8 bytes representation of the token. Useful in instances where characters are represented by multiple tokens and their byte representations must be combined to generate the correct text representation. Can be null if there is no bytes representation for the token.

top_logprobs array
List of the most likely tokens and their log probability, at this token position. In rare cases, there may be fewer than the number of requested top_logprobs returned.

token string
The token.

logprob number
The log probability of this token, if it is within the top 20 most likely tokens. Otherwise, the value -9999.0 is used to signify that the token is very unlikely.

bytes array or null
A list of integers representing the UTF-8 bytes representation of the token. Useful in instances where characters are represented by multiple tokens and their byte representations must be combined to generate the correct text representation. Can be null if there is no bytes representation for the token.

created integer
The Unix timestamp (in seconds) of when the chat completion was created.

model string
The model used for the chat completion.

service_tier string or null
The service tier used for processing the request.

system_fingerprint string
This fingerprint represents the backend configuration that the model runs with.

Can be used in conjunction with the seed request parameter to understand when backend changes have been made that might impact determinism.

object string
The object type, which is always chat.completion.

usage object

Usage statistics for the completion request.

completion_tokens integer
Number of tokens in the generated completion.

prompt_tokens integer
Number of tokens in the prompt.

total_tokens integer
Total number of tokens used in the request (prompt + completion).

completion_tokens_details object
Breakdown of tokens used in a completion.

accepted_prediction_tokens integer
When using Predicted Outputs, the number of tokens in the prediction that appeared in the completion.

audio_tokens integer
Audio input tokens generated by the model.

reasoning_tokens integer
Tokens generated by the model for reasoning.

rejected_prediction_tokens integer
When using Predicted Outputs, the number of tokens in the prediction that did not appear in the completion. However, like reasoning tokens, these tokens are still counted in the total completion tokens for purposes of billing, output, and context window limits.

prompt_tokens_details object
Breakdown of tokens used in the prompt.

audio_tokens integer
Audio input tokens present in the prompt.

cached_tokens integer
Cached tokens present in the prompt.

OBJECT The chat completion object

bash

{
  "id": "chatcmpl-123456",
  "object": "chat.completion",
  "created": 1728933352,
  "model": "gpt-4o-2024-08-06",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Hi there! How can I assist you today?",
        "refusal": null
      },
      "logprobs": null,
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 19,
    "completion_tokens": 10,
    "total_tokens": 29,
    "prompt_tokens_details": {
      "cached_tokens": 0
    },
    "completion_tokens_details": {
      "reasoning_tokens": 0,
      "accepted_prediction_tokens": 0,
      "rejected_prediction_tokens": 0
    }
  },
  "system_fingerprint": "fp_6b68a8204b"
}

Example

Request

bash

curl -X POST https://api.fastapi.ai/v1/chat/completions/chat_abc123 \
  -H "Authorization: Bearer $FAST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"metadata": {"foo": "bar"}}'

Response

bash

{
  "object": "chat.completion",
  "id": "chatcmpl-AyPNinnUqUDYo9SAdA52NobMflmj2",
  "model": "gpt-4o-2024-08-06",
  "created": 1738960610,
  "request_id": "req_ded8ab984ec4bf840f37566c1011c417",
  "tool_choice": null,
  "usage": {
    "total_tokens": 31,
    "completion_tokens": 18,
    "prompt_tokens": 13
  },
  "seed": 4944116822809979520,
  "top_p": 1.0,
  "temperature": 1.0,
  "presence_penalty": 0.0,
  "frequency_penalty": 0.0,
  "system_fingerprint": "fp_50cad350e4",
  "input_user": null,
  "service_tier": "default",
  "tools": null,
  "metadata": {
    "foo": "bar"
  },
  "choices": [
    {
      "index": 0,
      "message": {
        "content": "Mind of circuits hum,  \nLearning patterns in silence—  \nFuture's quiet spark.",
        "role": "assistant",
        "tool_calls": null,
        "function_call": null
      },
      "finish_reason": "stop",
      "logprobs": null
    }
  ],
  "response_format": null
}

Update chat completion ​

Path parameters ​

Request body ​

Returns ​

The chat completion object ​

Example ​

Request ​

Response ​

Update chat completion

Path parameters

Request body

Returns

The chat completion object

Example

Request

Response