Add lean-ctx skill (#749)

Made-with: Cursor

Co-authored-by: Yves Gugger <yvesgugger@Yvess-MacBook-Pro.local>

README.md

@@ -121,6 +121,7 @@ Claude Skills are customizable workflows that teach Claude how to perform specif
 - [iOS Simulator](https://github.com/conorluddy/ios-simulator-skill) - Enables Claude to interact with iOS Simulator for testing and debugging iOS applications. *By [@conorluddy](https://github.com/conorluddy)*
 - [jules](https://github.com/sanjay3290/ai-skills/tree/main/skills/jules) - Delegate coding tasks to Google Jules AI agent for async bug fixes, documentation, tests, and feature implementation on GitHub repos. *By [@sanjay3290](https://github.com/sanjay3290)*
 - [LangSmith Fetch](./langsmith-fetch/) - Debug LangChain and LangGraph agents by automatically fetching and analyzing execution traces from LangSmith Studio. First AI observability skill for Claude Code. *By [@OthmanAdi](https://github.com/OthmanAdi)*
+- [lean-ctx](https://github.com/yvgude/lean-ctx) - MCP server and context runtime for AI coding agents: session caching, AST-aware compression, and 90+ shell patterns to reduce token usage. Supports Claude Code, Cursor, Copilot, and other integrations. Install the Claude Code skill with `lean-ctx init --agent claude-code`; docs at [leanctx.com](https://leanctx.com). *By [@yvgude](https://github.com/yvgude)*
 - [MCP Builder](./mcp-builder/) - Guides creation of high-quality MCP (Model Context Protocol) servers for integrating external APIs and services with LLMs using Python or TypeScript.
 - [move-code-quality-skill](https://github.com/1NickPappas/move-code-quality-skill) - Analyzes Move language packages against the official Move Book Code Quality Checklist for Move 2024 Edition compliance and best practices.
 - [Playwright Browser Automation](https://github.com/lackeyjb/playwright-skill) - Model-invoked Playwright automation for testing and validating web applications. *By [@lackeyjb](https://github.com/lackeyjb)*