Implements RetryProvider, RotatedProvider, and ProviderCircuitBreaker for automatic fallback between multiple AI providers. Self-contained and reusable for any multi-provider system requiring retry logic with circuit breaker semantics.

Provides QuotaCache with TTL-based expiration and ErrorCounter with rolling window for tracking provider health, plus a recursive-descent condition parser for YAML-based routing rules. Reusable for any rate-limited service requiring health-aware routing.

CDPSession wrapper for Chrome DevTools Protocol with shared browser pooling, reference counting, idle shutdown, stealth injection, turnstile bypass, and Android WebView support. Well-crafted and could be extracted as a standalone library for browser automation.

Faithful Python transcription of ChatGPT's sentinel challenge VM, enabling programmatic solving of Cloudflare Turnstile challenges. Demonstrates non-obvious reverse-engineering skill and is self-contained for reuse in other projects needing Turnstile bypass.

Thread-safe singleton token manager with file-based persistence, TTL-based expiration, and cross-process locking via file locks. Reusable for any OAuth token caching scenario requiring persistence across process restarts.

Defines AbstractProvider, AsyncGeneratorProvider, and ProviderModelMixin with parameter handling, auth caching, and timeout logic. The foundation for all provider implementations, demonstrating clean abstraction design for pluggable backends.