MCP is an open protocol that lets AI apps call tools and read data on servers over stdio or Streamable HTTP. How it works and how 17 AI tools connect to it.
VS Code Copilot reads copilot-instructions.md and AGENTS.md, loads MCP from .vscode/mcp.json, and compacts long chats. Cline and Continue add their own rules.
T3 Chat puts GPT-6, Claude, Gemini, and Kimi behind one picker for $8 a month. Long threads, files, and search cost more, so here is how to keep context lean.
Zed's Agent Panel loads one project instruction file (.rules first, then AGENTS.md or CLAUDE.md), takes @-mentions as context, and adds MCP via context_servers.
