HarnessAPI: A Skill-First Framework for Unified Streaming APIs and MCP Tools

HarnessAPI is a Python framework that turns one typed skill definition into both SSE-based HTTP APIs and zero-config MCP tools.

It uses a typed skill folder as the source of truth, with dynamic type propagation, OpenAPI/Swagger docs, and content negotiation support.

The paper reports 74% less framework-facing boilerplate than running separate FastAPI and FastMCP servers.

This could help AI tool developers ship agent-ready and human-facing interfaces from one codebase while reducing maintenance and schema drift.