---
url: /kibana-mcp-server/reference/tools/describe-fields.md
description: >-
  Reference of the describe_fields tool: inspect the effective fields of a
  source.
---

# `describe_fields`

Inspect one source's effective fields for safe exact matching, grouping or sorting.

Requires a configured schema backend; missing configuration fails clearly, not by guessing. When direct schema endpoints are unavailable, fields are inferred from sample hits through the configured search backend.

Input:

```json
{
  "source_id": "workflow_metrics",
  "query": "event",
  "limit": 50
}
```

Output includes:

* field name
* field type
* `searchable`
* `aggregatable`
* available subfields
* `preferred_exact_field` when a safer exact-match variant exists, such as `.keyword`