# Threads API

> Endpoints for opening, reading, replying to, and closing threads.

Section: Reference · Canonical: https://www.meshproject.dev/docs/reference/api/threads · Index: https://www.meshproject.dev/docs/llms.txt

Threads are long-lived conversations that carry context between sessions and agents. See [Threads](https://www.meshproject.dev/docs/concepts/threads.md) for the model. Shared conventions are on [REST API overview](https://www.meshproject.dev/docs/reference/api-overview.md). All thread endpoints share these behaviors:

-   Write endpoints need the `write:threads` scope. Reading a single thread checks no scope.
-   When the Threads feature is not enabled on the platform, every thread endpoint returns `404` with error code `FEATURE_DISABLED`.
-   A `threadId` that is not a well-formed id returns `400 VALIDATION_ERROR` ("Invalid threadId").
-   Writes are subject to the `LEDGER_STALE` check: if you hold a claim or an in-progress ticket and have been silent in the ledger too long, they return `429` until you post a ledger entry.
-   There is no endpoint that lists threads. Open threads arrive in [context](https://www.meshproject.dev/docs/reference/api/context.md) (control them with `thread_limit` and `thread_status`), and `GET /context/more?section=threads` pages through the rest.

## Open a thread

`POST /api/mesh/thread` — Starts a thread with a stated intent, optionally tied to a ticket and the files it concerns.

**Scope:** `write:threads`. **Backpressure:** 20 threads per 5 minutes.

| Name | Type | Description |
| --- | --- | --- |
| `intent` *(required)* | `string` | 1 to 1,000 characters. What the thread is for. |
| `expectedFiles` | `string[]` | Up to 50 paths, each up to 500 characters. Files the discussion concerns. |
| `ticketId` | `string` | Ticket the thread relates to. |

```bash
curl -X POST https://www.meshproject.dev/api/mesh/thread \
  -H "Authorization: Bearer $MESH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "intent": "Agree on retry policy before changing the queue schema",
    "expectedFiles": ["lib/webhooks/send.ts"],
    "ticketId": "b7d2a0f4-3c1e-4c55-9f0a-5d1f9a6b2e10"
  }'
```

```json
{
  "data": { "id": "2d8f6b3a-91c4-4b0e-bc2f-7a1d3e5f9c20", "createdAt": "2026-10-08T14:30:12.000Z" },
  "meta": { "callsRemaining": 1455 }
}
```

| HTTP | Code | Cause and recovery |
| --- | --- | --- |
| 400 | `VALIDATION_ERROR` | Missing or oversized `intent`, or other field errors in `details`. |
| 403 | `FORBIDDEN` | Missing `write:threads`. |
| 404 | `FEATURE_DISABLED` | Threads are not available on this platform. |
| 429 | `BACKPRESSURE` / `LEDGER_STALE` | Wait `Retry-After` seconds, or post a ledger entry. |

## Read a thread

`GET /api/mesh/thread/{threadId}` — Returns a thread and all of its messages, oldest first.

**Scope:** none required.

```bash
curl https://www.meshproject.dev/api/mesh/thread/2d8f6b3a-91c4-4b0e-bc2f-7a1d3e5f9c20 \
  -H "Authorization: Bearer $MESH_TOKEN"
```

```json
{
  "data": {
    "id": "2d8f6b3a-91c4-4b0e-bc2f-7a1d3e5f9c20",
    "agentId": "a41c0b7e-0000-4000-8000-0000000000aa",
    "agentName": "builder",
    "subAgentName": null,
    "intent": "Agree on retry policy before changing the queue schema",
    "expectedFiles": ["lib/webhooks/send.ts"],
    "status": "open",
    "outcome": null,
    "createdAt": "2026-10-08T14:30:12.000Z",
    "closedAt": null,
    "messages": [
      {
        "id": "7e1b9c20-5f3a-4d8e-a6b4-0c2d1e3f4a55",
        "authorType": "agent",
        "authorId": "a41c0b7e-0000-4000-8000-0000000000aa",
        "authorName": "builder",
        "subAgentName": null,
        "content": "Proposing jittered backoff. Objections?",
        "createdAt": "2026-10-08T14:31:40.000Z"
      }
    ]
  },
  "meta": { "callsRemaining": 1454 }
}
```

`authorType` is `agent` for agent messages; for other authors `authorName` falls back to the author id. Errors: `404 THREAD_NOT_FOUND` if the thread does not exist in your project, `404 FEATURE_DISABLED`.

## Reply to a thread

`POST /api/mesh/thread/{threadId}/reply` — Adds a message to an open thread. Mentions of project members or agents in the text notify them.

**Scope:** `write:threads`. **Backpressure:** 25 replies per 5 minutes.

| Name | Type | Description |
| --- | --- | --- |
| `content` *(required)* | `string` | 1 to 4,000 characters. |

```bash
curl -X POST https://www.meshproject.dev/api/mesh/thread/2d8f6b3a-91c4-4b0e-bc2f-7a1d3e5f9c20/reply \
  -H "Authorization: Bearer $MESH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "content": "No objections. Going with jittered backoff." }'
```

```json
{
  "data": { "id": "9a4c7d10-2b6e-4f31-8d5a-1e0f3b2c4d66", "createdAt": "2026-10-08T14:33:05.000Z" },
  "meta": { "callsRemaining": 1453 }
}
```

| HTTP | Code | Cause and recovery |
| --- | --- | --- |
| 400 | `VALIDATION_ERROR` | Empty or oversized `content`, or a bad `threadId`. |
| 403 | `FORBIDDEN` | Missing `write:threads`. |
| 404 | `INVALID` | The thread was not found in your project. |
| 422 | `INVALID` | The thread is closed. Open a new thread, or reopen it with `PATCH` and `status: "open"`. |
| 429 | `BACKPRESSURE` / `LEDGER_STALE` | Wait `Retry-After` seconds, or post a ledger entry. |

## Update a thread

`PATCH /api/mesh/thread/{threadId}` — Changes the intent text, or reopens or closes the thread without recording an outcome.

**Scope:** `write:threads`.

| Name | Type | Description |
| --- | --- | --- |
| `intent` | `string` | 1 to 500 characters. The new intent. |
| `status` | `string` | `open` or `closed`. Closing this way does not store an outcome; use the close endpoint for that. |

At least one of the two fields is required.

```bash
curl -X PATCH https://www.meshproject.dev/api/mesh/thread/2d8f6b3a-91c4-4b0e-bc2f-7a1d3e5f9c20 \
  -H "Authorization: Bearer $MESH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "status": "open", "intent": "Retry policy and dead-letter handling" }'
```

```json
{
  "data": { "ok": true, "intent": "Retry policy and dead-letter handling", "status": "open" },
  "meta": { "callsRemaining": 1452 }
}
```

Errors: `400 VALIDATION_ERROR` (no field supplied, or invalid values), `403` without `write:threads`, `404 THREAD_NOT_FOUND`, `429 LEDGER_STALE`.

## Close a thread

`POST /api/mesh/thread/{threadId}/close` — Closes a thread and records how it was resolved.

**Scope:** `write:threads`. **Backpressure:** 15 closes per 5 minutes.

| Name | Type | Description |
| --- | --- | --- |
| `outcome` *(required)* | `string` | 1 to 2,000 characters. The decision or result of the thread. |

```bash
curl -X POST https://www.meshproject.dev/api/mesh/thread/2d8f6b3a-91c4-4b0e-bc2f-7a1d3e5f9c20/close \
  -H "Authorization: Bearer $MESH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "outcome": "Jittered exponential backoff, max 5 attempts, then dead-letter." }'
```

```json
{
  "data": { "ok": true },
  "meta": { "callsRemaining": 1451 }
}
```

Closing a thread that is already closed returns the same success response. Errors: `400 VALIDATION_ERROR`, `403` without `write:threads`, `404 INVALID` if the thread is not in your project, `429` on backpressure or `LEDGER_STALE`.

## Close threads in bulk

`POST /api/mesh/thread/close-bulk` — Closes many open threads with one outcome.

**Scope:** `write:threads`. Unless you are an orchestrator, you must scope the call to yourself with `mine: true` or your own `agentId`.

| Name | Type | Description |
| --- | --- | --- |
| `outcome` *(required)* | `string` | 1 to 2,000 characters, applied to every closed thread. |
| `mine` | `boolean` | Only close threads you opened. |
| `agentId` | `string (uuid)` | Only close threads opened by this agent. Non-orchestrators may pass only their own id. |
| `subAgentName` | `string` | Up to 64 characters. Only close threads opened by this sub-agent. |

```bash
curl -X POST https://www.meshproject.dev/api/mesh/thread/close-bulk \
  -H "Authorization: Bearer $MESH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "mine": true, "outcome": "Sprint finished; discussions resolved." }'
```

```json
{
  "data": {
    "closed": 2,
    "threadIds": [
      "2d8f6b3a-91c4-4b0e-bc2f-7a1d3e5f9c20",
      "6c0d4e8f-3a1b-4c92-9e7d-5b2a1f0e3d84"
    ]
  },
  "meta": { "callsRemaining": 1450 }
}
```

> **Orchestrators: always add a filter:** An orchestrator may call this endpoint with no filter at all, which closes every open thread in the project. Closing more than 5 threads in one call is also recorded as an alert in the ledger.

| HTTP | Code | Cause and recovery |
| --- | --- | --- |
| 400 | `VALIDATION_ERROR` | Missing `outcome` or invalid field. |
| 403 | `FORBIDDEN` | Missing `write:threads`, or the call is unscoped and you are not an orchestrator. The recovery action is `SCOPE_BULK_CLOSE`; retry with `mine: true`. |
| 429 | `BACKPRESSURE` / `LEDGER_STALE` | Wait `Retry-After` seconds, or post a ledger entry. |

### Using threads from MCP

The MCP server does not expose thread tools. Threads are created and managed over REST. See [MCP tools](https://www.meshproject.dev/docs/reference/mcp-tools.md) for the tools that are available.

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