Greptile Summary

Fixed critical rate-limit handling bug in Feishu typing indicator that caused infinite API retries when quota was exceeded (reported as 76,000+ calls in 8 hours).

Key changes:

• Extracted isFeishuBackoffError() helper that detects rate-limit conditions in both AxiosError and Feishu SDK error shapes (HTTP 429, codes 99991403/99991400)
• Modified addTypingIndicator() and removeTypingIndicator() to re-throw backoff errors instead of silently swallowing them, allowing the circuit breaker to trip after 2 failures
• Used Set-based approach for error codes, making it easy to add future codes
• Added distinct logging for rate-limit errors vs other non-critical failures
• Comprehensive test coverage with 11 unit tests covering various error shapes and edge cases

The implementation is clean, well-structured, and follows repository guidelines. No issues found.

Confidence Score: 5/5

• This PR is safe to merge with no risk
• The fix is well-targeted, solving a specific documented problem (Feishu typing indicator ignores 429/quota errors, causing infinite retry loop #28062) with a clean implementation. Comprehensive test coverage (11 tests) validates all error detection paths. The change is backwards compatible, maintains existing behavior for non-critical errors, and introduces no breaking changes. Code follows repository style guidelines and is properly documented.
• No files require special attention

_{Last reviewed commit: 559526d}

Thanks for the excellent catch @chatgpt-codex-connector! 🎯

You're right — the Feishu SDK can return a normal response with an API-level error code instead of throwing. This would bypass the catch block entirely and the circuit breaker would never trip.

Addressed in 4f201ae:

• Added hasBackoffCodeInResponse() helper to detect backoff codes in non-throwing SDK responses
• Both addTypingIndicator and removeTypingIndicator now check response codes before treating the result as success
• Added 7 new unit tests (total: 18)

To use Codex here, create a Codex account and connect to github.

Addressed Codex P2 review in 6d1adec — and found the issue also affects addTypingIndicator, not just removeTypingIndicator.

Root cause: throw new Error(...) inside try is caught by the surrounding catch. Since a plain Error has no .code property, isFeishuBackoffError() doesn't match it → silently swallowed → circuit breaker never trips.

Fix: Introduced FeishuBackoffError class extending Error with a numeric .code property. Since isFeishuBackoffError() already checks err.code, these errors are now correctly detected and re-thrown.

Added 5 new tests (total: 23), including a catch-rethrow simulation that proves the fix works end-to-end. 🎯