CodexSaver is an MCP tool that acts as a cost-aware router for Codex, delegating bounded tasks (tests, docs, search, explanation) to cheaper providers like DeepSeek while keeping Codex responsible for architecture, security, and final review. It uses Pi Agent as the default v3 worker for orchestration and supports legacy v1/v2 provider-backed delegation. The system includes protected paths, allowlisted commands, sandboxed patch application, and automatic Codex fallback for safety.