---
title: "Get span field definitions"
method: GET
path: "/v1/observability/spans/fields"
tags: ["beta.observability.spans"]
---

# Get span field definitions

`GET /v1/observability/spans/fields`

Get span field definitions

## Response `200`

Successful Response

- GetSpanFields
  - `field_definitions` OtelFieldDefinition[], required
    - `name` string, required
    - `label` string, required
    - `type` 'ENUM' | 'TEXT' | 'INT' | 'FLOAT' | 'BOOL' | 'TIMESTAMP' | 'ARRAY' | 'MAP', required
    - `group` string, nullable
    - `source_attribute_key` string, nullable — Raw OpenTelemetry attribute key this field is projected from, whether a span attribute (e.g. `gen_ai.request.model` for `request_model`) or a resource attribute (e.g. `service.name` for `service_name`). None when the field is a native OTLP field (like `span_name` or `trace_id`) or a nested attribute map (like `span_attributes`).
    - `supported_operators` string[], required
    - `supported_aggregations` MetricAggregation[], required

## 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

- **2026-09-23** `fa73befe1c61` — 30 warning, 36 info
  - added the new `EVALUATION_RUN_OUTPUT_RECORD_CONFLICT` enum value to the `detail/error_code/anyOf[subschema #1: ObservabilityErrorCode]/` response property for the response status `400`
  - added the new `EVALUATION_RUN_OUTPUT_RECORD_CONFLICT` enum value to the `detail/error_code/anyOf[subschema #1: ObservabilityErrorCode]/` response property for the response status `404`
  - added the new `EVALUATION_RUN_OUTPUT_RECORD_CONFLICT` enum value to the `detail/error_code/anyOf[subschema #1: ObservabilityErrorCode]/` response property for the response status `408`
  - added the new `EVALUATION_RUN_OUTPUT_RECORD_CONFLICT` enum value to the `detail/error_code/anyOf[subschema #1: ObservabilityErrorCode]/` response property for the response status `409`
  - …62 more
- …earlier changes not shown

[Full history](https://skmtc.dev/mistral/apis/mistral-ai-api/changes/v1/observability/spans/fields/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/fa73befe1c61?raw)