---
title: "Changes to Get span field definitions"
method: GET
path: "/v1/observability/spans/fields"
---

# Changes to Get span field definitions

`GET /v1/observability/spans/fields`

> Every recorded change to this endpoint, newest first.

## Timeline

Changed in 1 of 3 revisions.

- **2026-08-14** `61436a496404` — 5 warning, 1 info

## Changes

- **2026-08-14** `61436a496404` — 5 warning, 1 info
  - 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`
  - 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 `422`
  - added the required property `field_definitions/items/supported_aggregations` to the response with the `200` status

---

[Operation](https://skmtc.dev/mistral/apis/mistral-ai-api/docs/v1/observability/spans/fields/get.md) · [API](https://skmtc.dev/mistral/apis/mistral-ai-api.md) · [Page](https://skmtc.dev/mistral/apis/mistral-ai-api/changes/v1/observability/spans/fields/get)