Add configurable runtime fallback message patterns

[zengxiaolou]

Summary

• add runtime_fallback.retry_on_message_patterns schema/config support so teams can define provider-specific retry text triggers without patching source
• wire configured patterns into runtime fallback classification for session.error, message.updated, and session.status flows while keeping default behavior unchanged
• add tests for configured no-available-accounts matching and document the new option in configuration reference

Validation

• bun test src/hooks/runtime-fallback/error-classifier.test.ts src/hooks/runtime-fallback/index.test.ts

---

Summary by cubic

Adds support for runtime_fallback.retry_on_message_patterns so teams can trigger fallback on provider-specific messages (via regex), not just status codes. Patterns are applied across session.error, message.updated, and session.status flows; defaults stay the same.

• New Features
  • New config option runtime_fallback.retry_on_message_patterns: string[] (regex strings), default [].
  • Message-based retry detection now merges built-in keywords with configured patterns.
  • Wired into isRetryableError and extractAutoRetrySignal and used by event and message update handlers.
  • Added tests for custom pattern matching (e.g., "no available accounts") and updated configuration docs with examples.

^{Written for commit b8c16ac. Summary will update on new commits.}

[github-actions]

All contributors have signed the CLA. Thank you! ✅
_{Posted by the CLA Assistant Lite bot.}

[cubic-dev-ai]

No issues found across 9 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Auto-approved: The PR safely introduces a new optional configuration for custom retry message patterns with appropriate regex handling, comprehensive tests, and no breaking changes to existing logic.}

---

Since this is your first cubic review, here's how it works:

• cubic automatically reviews your code and comments on bugs and improvements
• Teach cubic by replying to its comments. cubic learns from your replies and gets better over time
• Add one-off context when rerunning by tagging @cubic-dev-ai with guidance or docs links (including llms.txt)
• Ask questions if you need clarification on any suggestion

[zengxiaolou]

I have read the CLA Document and I hereby sign the CLA

[acamq]

@sisyphus-dev-ai

[sisyphus-dev-ai]

Review Summary

I've reviewed PR #2433 and verified the implementation.

Verification Results

Check	Status
Tests pass	63/63
TypeScript compiles	Clean
Code quality	Good
Follows existing patterns	Yes

Implementation Analysis

What this PR adds:

• New optional config retry_on_message_patterns: string[] for triggering runtime fallback on provider-specific error messages (via regex), not just HTTP status codes
• Properly wired into all three fallback flows: session.error, message.updated, and session.status
• Default value is [] (empty array), so existing behavior is unchanged

Code quality observations:

1. Proper regex compilation with error handling - compilePatterns() gracefully skips invalid regex patterns
2. Consistent pattern merging - Built-in patterns (AUTO_RETRY_SIGNAL_KEYWORD_PATTERNS) are merged with user-configured patterns
3. Backward compatible - All functions accepting the new parameter have = [] defaults
4. Good test coverage - 3 new test cases covering the feature:
   • Does NOT trigger without configured patterns (false positive protection)
   • DOES trigger when configured patterns match
   • Treats configured pattern matches as retryable errors

Documentation:

• Config reference updated with example and description

Recommendation

LGTM - This is a clean, well-structured addition that enables teams to handle provider-specific retry scenarios (like "no available accounts" messages) without code changes. The implementation follows existing patterns and maintains backward compatibility.

Ready to merge.