IDEMPOTENCY_KEY_REUSED

That idempotency key was used for a different request body.

HTTP status	422
Group	Platform
Retryable	No — sending it again changes nothing

What happened

A key identifies one request; reusing it for other content would make replay meaningless.

What to do

Use a new key, or resend the original body.

The problem document

Every error is application/problem+json (RFC 9457) with the same shape:

{
  "type": "https://docs.co-relayer.com/errors/idempotency-key-reused",
  "title": "That idempotency key was used for a different request body.",
  "status": 422,
  "detail": "A sentence about this specific occurrence.",
  "instance": "req_01JB…",
  "code": "IDEMPOTENCY_KEY_REUSED",
  "retryable": false,
  "hint": "Use a new key, or resend the original body."
}

See the error model for what each member means and how to handle unknown codes.