Version conflict

What it means

The If-Match version does not match the current version of the resource.

Common causes

• Someone changed the resource after you read it.
• The ETag you sent came from an older read.

What to do

Read the resource again for the new ETag, apply your change to the fresh copy, and send it with the new If-Match.

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 version_conflict and retryable: false.

Example

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

{
  "type": "https://api.tobie.team/problems/version_conflict",
  "title": "Version conflict",
  "status": 412,
  "detail": "The resource version does not match If-Match",
  "code": "version_conflict",
  "instance": "/v1/tasks/3f1c9d2e-7a4b-4c1e-9f0a-2b6d8e5c1a90",
  "requestId": "01JC0S7Z5F3X9QK2M4N6P8R0TV"
}