convention.sh is a hosted MCP server with 27 hand-tuned TypeScript conventions. Coding agents like Claude Code, Cursor, Codex, and Amp pull conventions just-in-time — so they don't thrash and you don't pay for tokens you don't need. Benchmarked on Claude Opus 4.7 to produce production-ready code 59% faster, 44% cheaper, and with 84% fewer input tokens vs baseline. Free tier available, no credit card required.

Hey PH! 👋 I'm Ryan, one of the engineers behind convention.sh. The spark for this came from watching AI coding agents repeatedly make the same TypeScript mistakes — reaching for any, skipping runtime validation, writing optional fields where discriminated unions belong, and overall being sloppy. The usual suspects. Rather than paste a wall of rules into every prompt (and burn tokens on rules the agent doesn't need), we built a hosted MCP server that delivers exactly the convention the agent needs, exactly when it needs it. 27 conventions so far, all hand-tuned. Free tier is available with no credit card required — get started by adding convention.sh to your IDE of choice at https://convention.sh

The "just-in-time" pull approach is really clever. Having the agent pull only what it needs based on what it's actually doing makes way more sense. The benchmarks are impressive - but I'm curious how they hold up across different project structures. Our codebase has a pretty opinionated setup with specific patterns for API routes, state management, and component architecture. Can you add custom conventions alongside the 27 built-in ones, or is it a fixed set?

convention.sh

Stop AI agents from writing sloppy TypeScript

Stop AI agents from writing sloppy TypeScript