Reason: Request Failed: 400 {"type":"error","error":

### Describe the bug

Sorry, your request failed. Please try again.

Client Request Id: 37d002d9-1b1a-4391-87c7-c5e78738a4d6

GH Request Id: C773:3572CB:8F80BEE:9D6A6D9:6A5F0843

Reason: Request Failed: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.1: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response."},"request_id":"req_011CdEgFCtmuNZwA4j7YktHw"}

### Affected version

_No response_

### Steps to reproduce the behavior

_No response_

### Expected behavior

_No response_

### Additional context

_No response_

The report names no files, tests, or entry points and provides no reproduction steps. Begin by reproducing the failed request using the supplied client and GitHub request IDs, then trace the request-handling path that constructs the assistant message; done means identifying and preventing the invalid request, with a regression test.

Written by the indexing model from the issue text.