---
title: "Thread Participants"
description: "REST endpoints for thread participants. Bearer-auth required."
section: "API"
group: "REST"
order: 69
---

## GET /api/thread-participants

List thread participants.

**Query parameters**

- `limit` (optional): Page size (1–100, default 100).
- `after` (optional): Keyset cursor — return the page after this row (next page).
- `before` (optional): Keyset cursor — return the page before this row (prev page).
- `ids` (optional): Comma-separated list of IDs. Narrows results to these IDs within the caller's accessible scope (does not bypass access checks).
- `filter` (optional): Nested filter expression (`<Entity>Filter`): AND/OR/NOT + per-field comparison operators + relation traversal. JSON-encoded on the query string.
- `orderBy` (optional): Multi-key sort (`<Entity>OrderBy[]`): array of `{ field: direction }` applied in order. Directions: asc/desc plus the four explicit nulls variants. JSON-encoded on the query string.
- `thread_id` (optional): Optional thread narrower. Admins see every participant when omitted; non-admin callers must scope by thread.
- `user_id` (optional): Shorthand: filter where `userId` equals this value.
- `agent_id` (optional): Shorthand: filter where `agentId` equals this value.
- `swarm_id` (optional): Shorthand: filter where `swarmId` equals this value.
- `last_read_message_id` (optional): Shorthand: filter where `lastReadMessageId` equals this value.

**Response**

```json
{
  "data": [
    {
      "id": "<...>",
      "threadId": "<...>",
      "userId": "<...>",
      "agentId": "<...>",
      "swarmId": "<...>",
      "externalIdentity": "<...>",
      "displayName": "<...>",
      "joinedAt": "<...>",
      "lastReadMessageId": "<...>",
      "lastReadAt": "<...>"
    }
  ],
  "pageInfo": {
    "total": "number",
    "hasNextPage": "boolean",
    "hasPreviousPage": "boolean",
    "startCursor": "string",
    "endCursor": "string"
  }
}
```

## POST /api/thread-participants

Add a thread participant

**Request body**

```json
{
  "threadId": "string",
  "userId?": "string",
  "agentId?": "string",
  "swarmId?": "string",
  "externalIdentity?": "string",
  "displayName?": "string"
}
```

**Response**

```json
{
  "id": "string",
  "threadId": "string",
  "userId": "string",
  "agentId": "string",
  "swarmId": "string",
  "externalIdentity": "string",
  "displayName": "string",
  "joinedAt": "string",
  "lastReadMessageId": "string",
  "lastReadAt": "string"
}
```

## GET /api/thread-participants/{id}

Get a thread participant by ID.

**Path parameters**

- `id` (required): Participant to retrieve.

**Response**

```json
{
  "id": "string",
  "threadId": "string",
  "userId": "string",
  "agentId": "string",
  "swarmId": "string",
  "externalIdentity": "string",
  "displayName": "string",
  "joinedAt": "string",
  "lastReadMessageId": "string",
  "lastReadAt": "string"
}
```

## DELETE /api/thread-participants/{id}

Remove a thread participant.

**Path parameters**

- `id` (required): Participant to remove.

**Response**

```json
{
  "success": "boolean"
}
```