Idempotent request in progress

What it means

A request with the same Idempotency-Key is still running.

Common causes

• A retry was sent before the first attempt finished.
• Two workers sent the same key at the same time.

What to do

Wait for the seconds in Retry-After, then retry with the same key and the same body. You will get the original result.

Retry: safe after a pause. Back off between attempts, and reuse the same Idempotency-Key for a write.

This response also carries Retry-After, the number of seconds to wait before you try again.

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

Example

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

{
  "type": "https://api.tobie.team/problems/idempotency_in_progress",
  "title": "Idempotent request in progress",
  "status": 409,
  "detail": "A request with this Idempotency-Key is in progress",
  "code": "idempotency_in_progress",
  "instance": "/v1/tasks",
  "requestId": "01JC0S7Z5F3X9QK2M4N6P8R0TV"
}