Show HN: PolyMCP – open-source toolkit to expose MCP tools and run agents

Hi HN — I’m the author of PolyMCP (MIT).

PolyMCP is a toolkit/runtime for the Model Context Protocol (MCP): it helps you build MCP tool servers (expose Python functions as tools over HTTP/stdio), connect multiple MCP servers, and run agents that orchestrate them with deploy-friendly guardrails.

Latest update is mostly reliability work: - OAuth2 (RFC 6749): client credentials + authorization code flows, refresh handling, basic retries - Docker executor cleanup fixes (Windows + Unix) - Better skills/tool matching + stdio server support - CodeAgent async handling + error recovery - Health checks, structured logging, and rate limiting

Repo: https://github.com/poly-mcp/Polymcp

If you’ve deployed MCP/agent systems: what tends to bite you first (auth, rate limits, observability, sandboxing)? I’m especially interested in OAuth2 edge cases and container lifecycle issues.