I built an MCP proxy that compresses tool schemas by 77%. Looking for testers to break it.
The "MCP eats my context window" complaint is real. I measured it: 57 tools across 4 servers = 7,528 tokens before the agent does anything.
So I built slim-mcp — a proxy that sits between your agent and your MCP servers. It replaces verbose JSON Schema with TypeScript-style parameter signatures in the description. Think caveman speak for tool definitions:
Before: {"type": "string", "description": "The owner of the repository"}
After: owner:s!
Result: 7,528 tokens → 1,750. 77% reduction.
We tested accuracy with 120 API calls against Claude Sonnet — zero failures at every compression level. But that's our tools and our prompts. I want to know if it holds with yours.
Looking for:
People running 5+ MCP servers (GitHub, Notion, Playwright, etc.) — the more tools, the better the test.
Cursor / Cline users who don't have Claude Code's built-in Tool Search
Anyone willing to try extreme mode and report if tool calls break
Default is standard (19% reduction, zero risk). The aggressive modes are opt-in.
--> npm install -g slim-mcp
Everything else — config, benchmarks, how it works — is in the README.
npm: npmjs.com/package/slim-mcp
GitHub: github.com/Joncik91/slim-mcp
The context window problem is an engineering problem, not a protocol flaw. MCP doesn't need to die — it needs better tooling.