# PATCH /api/v2/todos/{todo}

Update a todo

- MCP id: todos.update
- Scope: api:write:project_management
- Permission: project_management::manage_work_items
- Rate cost: 1 unit, write bucket. A write costs the same whatever `view` you ask for.
- Cache-Control: private, no-store

Partially updates one of your todos: absent keys are untouched, an empty body is rejected.

`todo_content` is the only writable key: a todo cannot be re-parented, so `drive_item_id` is not accepted, and `user_id` is never writable. Send `If-Match` with the `ETag` from your last read to detect a concurrent edit, which answers `412`. Treat it as best-effort only: this resource carries no concurrency token and `updated_at` is second-precision, so two writes inside the same second are indistinguishable. ⚠ This write is temporary by construction. Todos are a derived copy of document content: the next write to the source drive item (including a title-only `PATCH /api/v2/drive-items/{drive_item}`) deletes every todo for that item and rebuilds the set from the document HTML, so this edit is discarded the next time the document is touched. To change a todo's text durably, edit the task item in the document itself.

## Parameters
- todo (integer, path): The UserTodo's numeric id.
- view (string, optional): Which field set to render.
- X-Request-Id (header, optional): A correlation id of your own. It is recorded in our logs next to the server's request id but never returned: the response header always carries the server's id. A value that does not match the pattern is discarded silently, never rejected.
- If-Match (header, optional): The ETag a write is conditional on. A stale validator is 412 precondition-failed.

## Request body
- todo_content (string ≤ 65535, optional): The todo line as plain text.

Unknown keys are refused with `422` validation-failed, naming the key.

## Response 200
- id (integer, required): Unique identifier.
- user_id (integer, required, server-assigned): The user the todo belongs to. Always the authenticated caller: this collection has no way to read or write another user's todos.
- drive_item_id (integer, required): The drive item whose document this todo was parsed out of. Writable on create only; a todo cannot be re-parented. No relation object is exposed for it; read the document with `GET /api/v2/drive-items/{drive_item}`, which applies the drive access rules this collection does not. Archiving a drive item leaves its todos behind, so this id can name an item you can no longer read.
- todo_content (string, required, multiline): The todo line as plain text.
- created_at (timestamp (YYYY-MM-DDThh:mm:ssZ), required): Creation timestamp.
- updated_at (timestamp (YYYY-MM-DDThh:mm:ssZ), required): Last-write timestamp; use for incremental sync.
- user (Ref or UserSummary, required): The user the todo belongs to, always the authenticated caller. Expanding it with `?include=user` additionally requires the `users::read` permission and a token scope covering the users prefix.
- links (UserTodoLinks, required)
  - self (url, required): The canonical URI of this record.

## Errors
- 403 forbidden-by-policy | insufficient-permission | insufficient-token-scope: Forbidden.
- 412 precondition-failed: Precondition failed.
- 415 unsupported-media-type: Unsupported media type.
- 422 unprocessable-relationship | validation-failed: Unprocessable content.
- 400 idempotency-key-required | invalid-cursor | invalid-query-parameter | malformed-request | unsupported-parameter: Bad request.
- 401 token-expired | unauthenticated: Unauthenticated.
- 404 endpoint-not-found | resource-not-found: Not found.
- 406 not-acceptable: Not acceptable.
- 429 rate-limit-exceeded: Too many requests.
- 500 internal-error: Server error.
- 503 tenant-unavailable: Service unavailable.

## Example
```bash
curl -X PATCH \
  'https://<your-url>/api/v2/todos/1' \
  -H 'Authorization: Bearer <token>' \
  -H 'Accept: application/json' \
  -H 'Content-Type: application/json' \
  -H 'If-Match: *' \
  -d '{
    "todo_content": "Confirm the kick-off date with the client before Friday"
  }'
```