---
title: "List an optimization's trials with their observation runs (paginated)"
method: GET
path: "/v1/observability/optimizations/{optimization_id}/trials"
tags: ["beta.observability.evaluations.optimizations"]
---

# List an optimization's trials with their observation runs (paginated)

`GET /v1/observability/optimizations/{optimization_id}/trials`

## Request

- Base URL: `https://api.mistral.ai`
- URL: `https://api.mistral.ai/v1/observability/optimizations/{optimization_id}/trials`
- Auth: HTTP bearer
- TypeScript: <https://skmtc.dev/mistral/apis/mistral-ai-api/docs/v1/observability/optimizations/:optimization_id/trials/get.ts> (a function with typed inputs; its response is checked against the schema)

List an optimization's trials with their observation runs (paginated)

## Path parameters

- `optimization_id` string, uuid, required

## Query parameters

- `page_size` integer
- `page` integer

## Response `200`

Successful Response

- ListOptimizationTrialsResponse
  - `trials` PaginatedResultOptimizationTrialWithObservations, required
    - `results` OptimizationTrialWithObservations[]
      - `id` string, uuid, required
      - `created_at` string, date-time, required
      - `updated_at` string, date-time, required
      - `deleted_at` string, date-time, nullable, required
      - `optimization_id` string, uuid, required
      - `algorithm_trial_key` string, required
      - `status` string, required
      - `parent_trial_id` string, uuid, nullable
      - `hypothesis` string, nullable
      - `resolution` string, nullable
      - `metadata_` object, required
      - `observations` OptimizationTrialObservation[]
        - `observation_type` string, nullable
        - `score` number, nullable
        - `metadata` object
        - `run` EvaluationRunV2Response, required
          - `id` string, uuid, required
          - `created_at` string, date-time, required
          - `updated_at` string, date-time, required
          - `deleted_at` string, date-time, nullable, required
          - `creator_id` string, uuid, required
          - `evaluation_id` string, uuid, required
          - `name` string, required
          - `description` string, nullable, required
          - `tags` string[], required
          - `metadata_` object, required
          - `num_generations` integer, required
          - `run_info` object, nullable
          - `status` string
          - `dataset_id` string, uuid, nullable
          - `evaluators` EvaluatorV2[], required
            - `id` string, uuid, required
            - `created_at` string, date-time, required
            - `updated_at` string, date-time, required
            - `deleted_at` string, date-time, nullable, required
            - `name` string, required
            - `description` string, nullable, required
            - `tags` string[], required
            - `num_scores` integer, required
            - `goal` GoalSpec
              - …
            - `aggregate_goal` GoalSpec
              - …
            - `statistics` union[], nullable
              - …
            - `weight` number
            - `direction` 'maximize' | 'minimize', nullable
            - `min_value` number, nullable
            - `max_value` number, nullable
          - `run_evaluators` EvaluatorV2[]
            - `id` string, uuid, required
            - `created_at` string, date-time, required
            - `updated_at` string, date-time, required
            - `deleted_at` string, date-time, nullable, required
            - `name` string, required
            - `description` string, nullable, required
            - `tags` string[], required
            - `num_scores` integer, required
            - `goal` GoalSpec
              - …
            - `aggregate_goal` GoalSpec
              - …
            - `statistics` union[], nullable
              - …
            - `weight` number
            - `direction` 'maximize' | 'minimize', nullable
            - `min_value` number, nullable
            - `max_value` number, nullable
          - `system` SystemV2
            - `id` string, uuid, required
            - `created_at` string, date-time, required
            - `updated_at` string, date-time, required
            - `deleted_at` string, date-time, nullable, required
            - `name` string, required
            - `params` object, required
          - `statistics` object
          - `goal_results` object
          - `passed` boolean, nullable
          - `run_scores` object
          - `optimization` RunOptimizationRef: Typed run→optimization back-ref, derived at read from the optimization_run link. Not stored on the run (single source of truth = optimization_run); lets a run row show its optimization (id + name) without an extra request per run.
            - `optimization_id` string, uuid, required
            - `name` string, required
    - `count` integer, required
    - `next` string, nullable
    - `previous` string, nullable

## 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

- **2026-10-12** `6c349f3bdef6`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/mistral/apis/mistral-ai-api/changes/v1/observability/optimizations/:optimization_id/trials/get.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/08a585fb75bc?raw)