---
title: "List declared metadata columns"
method: GET
path: "/metadata_columns"
tags: ["metadata-columns"]
---

# List declared metadata columns

`GET /metadata_columns`

(reserved for future use) Lists the metadata columns declared for the tenant. These are materialized as typed LanceDB columns (with scalar indices) at ingestion and are the set of columns usable by authz policies and search metadata\_filter.

Required roles: All

## Response `200`

Declared metadata columns

- MetadataColumnList
  - `columns` MetadataColumn[], required
    - `key` string, required — Metadata key name (also the LanceDB column source name).
    - `type` 'string' | 'integer', required — Column type. Only string / integer (scalar-indexable) are allowed.
    - `filter_only` boolean — When true, the value is kept only as a LanceDB column for filtering and is not included in chunk bodies or API responses.
    - `index_type` 'btree' | 'bitmap' — Scalar index type actually applied to the column. Defaults to BTREE for integer and BITMAP for string when not specified at creation; override for cardinality (e.g. high-cardinality string -> btree).
    - `created_at` string, nullable

## Other responses

- `401` — Unauthorized - Authentication failed
- `403` — Forbidden - requires an API key with All permission

---

[API](https://skmtc.net/qlonolink/apis/qaip-apis.md) · [All operations](https://skmtc.net/qlonolink/apis/qaip-apis/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/qlonolink/qaip-apis/revisions/f5f5994dfe05/schema)