Idempotency key required

What it means

This write needs an Idempotency-Key header and the request did not send one.

Common causes

• A POST that creates something was sent without Idempotency-Key.
• A batch (POST /v1/tasks:batch) was sent without one.

What to do

Generate a new UUID, send it as Idempotency-Key, and reuse that same key when you retry this write. See Idempotency.

Retry: only after a fix. The same request fails the same way until you change the request, the credential or the resource.

Over MCP, the same failure is a tool result with isError: true, the code idempotency_key_required and retryable: false.

Example

A response body for this problem. The detail and instance vary with the request.

{
  "type": "https://api.tobie.team/problems/idempotency_key_required",
  "title": "Idempotency key required",
  "status": 400,
  "detail": "An Idempotency-Key header is required",
  "code": "idempotency_key_required",
  "instance": "/v1/tasks",
  "requestId": "01JC0S7Z5F3X9QK2M4N6P8R0TV"
}