[autoantohaki]

Requested by mau

Summary

Before: requests that were the client's fault came back as 500 Internal Server Error on /v1/chat and /v1/chat/stream. That covered malformed JSON, whitespace-only input (which passed the schema and was then rejected by the runner), and bodies over the 1 MB limit. On the stream endpoint, blank input even got a 200 followed by an error event. Each one was also logged as a server failure.

After: malformed JSON and blank input return 400, oversized bodies return 413, and the agent is never invoked for any of them.

How: readJson throws a small RequestError carrying its status, the request schema rejects whitespace-only input, and both handlers map errors to a status through one errorStatus helper. A new test covers all three cases on both endpoints. It fails on main with expected 500 to be 400 and passes here. docs/http-api.md now lists the status codes.

Verification

• npm run verify (format, lint, types, tests with coverage, and build all pass locally)
• Tests do not require live credentials
• Documentation updated
• No secrets or machine-specific paths added