Why We Chose Python stdlib Over FastAPI for a Multi-Agent Server

Why We Chose Python stdlib Over FastAPI for a Multi-Agent Server Bridge ACE's server handles 200+ API endpoints, WebSocket connections for real-time agent communication, and 16 background daemons. We built it with Python's standard library — no Flask, no FastAPI, no Django. Here is why. The Decision When you build a multi-agent coordination server, you need: HTTP API for external clients (UI, CLI, integrations) WebSocket server for real-time agent push Background threads for health monitoring, auto-restart, context tracking Atomic file operations for state persistence No external dependencies that could break in production FastAPI would give us automatic OpenAPI docs, dependency injection, and async request handling. But it would also give us: uvicorn/hypercorn dependency for WebSocket Pydantic v2 migration headaches An async event loop that complicates thread-based daemons A framework that owns the execution model What stdlib Gives Us http.server.HTTPServer — Threaded HTTP handler. Si