---
title: "Run Judge on an event based on the given options"
method: POST
path: "/v1/observability/chat-completion-events/{event_id}/live-judging"
tags: ["beta.observability.chat_completion_events"]
---

# Run Judge on an event based on the given options

`POST /v1/observability/chat-completion-events/{event_id}/live-judging`

Run Judge on an event based on the given options

## Path parameters

- `event_id` string, uuid, required

## Request body

- JudgeChatCompletionEventRequest
  - `judge_definition` CreateJudgeRequest, required
    - `name` string, required
    - `description` string, required
    - `model_name` string, required
    - `output` union, required
      - JudgeClassificationOutput
        - `type` 'CLASSIFICATION'
        - `options` JudgeClassificationOutputOption[], required
          - `value` string, required
          - `description` string, required
      - JudgeRegressionOutput
        - `type` 'REGRESSION'
        - `min` number
        - `min_description` string, required
        - `max` number
        - `max_description` string, required
    - `instructions` string, required
    - `tools` string[], required

## Response `200`

Successful Response

- JudgeOutput
  - `analysis` string, required
  - `answer` union, required
    - string
    - number

## Other responses

- `400` — Bad Request - Invalid request parameters or data
- `404` — Not Found - Resource does not exist
- `408` — Request Timeout - Operation timed out
- `409` — Conflict - Resource conflict
- `422` — Unprocessable Entity - Validation error

## Changes

- **2026-08-14** `61436a496404` — 5 warning
  - added the new `OPTIMIZATION_TRIAL_KEY_ALREADY_EXISTS` enum value to the `detail/error_code/anyOf[subschema #1: ObservabilityErrorCode]/` response property for the response status `400`
  - added the new `OPTIMIZATION_TRIAL_KEY_ALREADY_EXISTS` enum value to the `detail/error_code/anyOf[subschema #1: ObservabilityErrorCode]/` response property for the response status `404`
  - added the new `OPTIMIZATION_TRIAL_KEY_ALREADY_EXISTS` enum value to the `detail/error_code/anyOf[subschema #1: ObservabilityErrorCode]/` response property for the response status `408`
  - added the new `OPTIMIZATION_TRIAL_KEY_ALREADY_EXISTS` enum value to the `detail/error_code/anyOf[subschema #1: ObservabilityErrorCode]/` response property for the response status `409`
  - …1 more

[Change history](https://skmtc.dev/mistral/apis/mistral-ai-api/changes/v1/observability/chat-completion-events/:event_id/live-judging/post.md)

---

[API](https://skmtc.dev/mistral/apis/mistral-ai-api.md) · [All operations](https://skmtc.dev/mistral/apis/mistral-ai-api/llms.txt) · [OpenAPI document](https://skmtc.dev/mistral/apis/mistral-ai-api/revisions/4cb0b5382d4f?raw)