> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bigdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# bigdata_list_tags

> List tags on private documents with document counts for corpus organisation discovery.

## Overview

List Private Content Tags returns the tags attached to the user's private documents, each with a document count. It gives a clear picture of how the private corpus is organised — brokers, email senders and recipients, connector labels, and custom topic tags — without paginating through documents.

## When to Use

List Private Content Tags is ideal for:

* **Broker inventory:** Seeing which brokers appear in investment research (`broker:`)
* **Email organisation:** Listing senders (`from:`) or recipients (`to:`) across the private email corpus
* **Connector labels:** Discovering `label:` tags that correspond to connected sources
* **Custom topics:** Exploring user-defined prefixes such as `topic:`
* **Search preparation:** Confirming a tag exists and has documents before a tag-scoped search

## How It Works

1. Call `bigdata_list_tags` with a `prefix` to focus on a tag family
2. Review each tag's `name` and `file_count`
3. Use the returned tag names to filter [`bigdata_list_documents`](/mcp-reference/tools/bigdata-list-documents) or scope [`bigdata_search`](/mcp-reference/tools/bigdata-search)

## Parameters

| Parameter | Type   | Required | Description                                                                        |
| --------- | ------ | -------- | ---------------------------------------------------------------------------------- |
| `prefix`  | string | No       | Filter tags whose `name` starts with this string. Recommended for focused results. |

### Important Notes

* Prefer always passing a `prefix`. Without it, accounts with many tags can return a very large response
* Include the trailing colon for auto-tag families: `broker:`, not `broker`
* User-defined tags typically follow the `prefix:value` convention

### Known auto-tag prefixes

| Prefix    | Meaning                                    |
| --------- | ------------------------------------------ |
| `broker:` | Broker tags on investment-research content |
| `from:`   | Email sender tags                          |
| `to:`     | Email recipient tags                       |
| `label:`  | Connector-label tags                       |

## Data Returned

An array of tag objects:

| Field        | Description                          |
| ------------ | ------------------------------------ |
| `name`       | Full prefixed tag string             |
| `file_count` | Number of documents carrying the tag |

## Practical Tips

### Quantitative answers

Use `file_count` to summarize coverage — for example, how many documents are available from each broker, or how many emails came from a given sender.

### Tag-scoped search

Pass the exact tag name into [`bigdata_search`](/mcp-reference/tools/bigdata-search) context as `tags: <name>` — for example `tags: broker:Goldman Sachs`.

### Empty tags

Tags with `file_count: 0` are registered but currently have no documents attached. Mention them only when reviewing empty or unused tags.