# Update Thread

Updates thread properties including tags and agent assignment.

- threadId (string), required

  The unique thread identifier (UUID)

* tags (array)

  Array of string tags (replaces existing tags)

- agent_id (string)

  New agent to assign to the thread. The agent must have a human-backed side.

* env (object | null)

  Replaces thread environment values.
  Values must be strings.
  `null` clears the environment.

- env_types (object)

  Display types for a replacement `env`.
  A matching key with `text` permits display.
  Other values use `secret`.

* env_patch (object)

  Adds or replaces individual environment values.
  Keys must be non-empty after trimming.
  Values must be non-null.
  Values are converted to strings.

- env_type_patch (object)

  Changes display types for existing environment keys.
  Use `text` or `secret`.
  A key without a matching environment value returns `400`.

* env_delete (string\[])

  Removes the named environment keys and their display types.

Use either replacement fields or patch fields in one request.
Patch fields operate on the stored environment.
The response includes `env_types` but omits environment values.

### Errors

The route returns `400` for invalid JSON, invalid field types, invalid environment patches, or an empty update.
An `agent_id` that is not a string returns `400`.
An unknown agent returns `404`.
An agent without a human-backed side returns `400`.

### Response

Returns the updated thread object.

- id (string), required

  Thread identifier

* agent_id (string), required

  The agent name associated with this thread

- user_id (string | null)

  User identifier if set

* tags (array), required

  Array of string tags

- created_at (number), required

  Unix timestamp in seconds

```bash cURL
curl -X PATCH https://your-worker.workers.dev/api/threads/550e8400-e29b-41d4-a716-446655440000 \
  -H "Authorization: Bearer $STANDARD_AGENTS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "tags": ["support", "escalated", "priority"]
  }'
```

```typescript JavaScript
const response = await fetch(
  'https://your-worker.workers.dev/api/threads/550e8400-e29b-41d4-a716-446655440000',
  {
    method: 'PATCH',
    headers: { Authorization: `Bearer ${token}`, 'Content-Type': 'application/json' },
    body: JSON.stringify({
      tags: ['support', 'escalated', 'priority']
    })
  }
);
const result = await response.json();
```

```json 200
{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "agent_id": "support_agent",
  "user_id": "user_abc123",
  "tags": ["support", "escalated", "priority"],
  "created_at": 1699900000
}
```

```json 400
{
  "error": {
    "code": "bad_request",
    "message": "No valid fields to update"
  },
  "requestId": "0b3c1f0e-7f0a-4a55-9c58-2f6f5a0f6f0e"
}
```

```json 404
{
  "error": {
    "code": "not_found",
    "message": "Thread not found: 550e8400-e29b-41d4-a716-446655440000"
  },
  "requestId": "0b3c1f0e-7f0a-4a55-9c58-2f6f5a0f6f0e"
}
```