[benbrandt]

Summary

Once a v2 prompt has been inserted, its response acknowledges insertion and cannot report later processing failures. The dual-version example previously rethrew non-cancellation errors and only logged them, leaving clients without an idle update.

• Report non-cancellation failures with an idle state_update carrying stopReason: "error".
• Preserve RequestError code, message, and data; map ordinary exceptions to internal errors.
• Keep cancellation reporting as idle/cancelled.
• Construct the Agent message inside the protected processing path, after echoing the inserted user message.
• Reserve the outer catch for failures to deliver completion, such as transport failures.

No schema changes or new test files.

Validation

• npm run check passed (generation consistency, lint, formatting, spellcheck, build, 976 existing tests, and TypeDoc verification).
• Exercised the compiled example over stdio for success, injected authentication failure, injected ordinary failure, and cancellation. Each produced a successful insertion receipt, matching user-message echo, the expected idle outcome, and accepted a subsequent prompt.
• git diff --check passed.