What is MCP?

The Model Context Protocol (MCP) is an open standard created by Anthropic that lets AI assistants connect to external tools and data sources. Instead of being limited to what the AI knows, MCP servers give your assistant the ability to read files, query databases, search the web, manage GitHub repos, and much more. MCP has been adopted by Claude Desktop, Claude Code, Cursor, VS Code (via Copilot), Windsurf, and Zed.

// Claude Desktop — ~/.claude/claude_desktop_config.json
{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@anthropic-ai/mcp-filesystem", "/home/user/projects"]
    },
    "github": {
      "command": "npx",
      "args": ["-y", "@anthropic-ai/mcp-github"],
      "env": { "GITHUB_TOKEN": "ghp_xxxxxxxxxxxx" }
    }
  }
}

// Verify connection
// Ask Claude: "List my MCP tools" → should show filesystem + GitHub tools

Config file locations by client

Each AI client stores its MCP configuration in a different file and location. Claude Desktop uses claude_desktop_config.json in the app data directory. Claude Code uses .mcp.json in the project root. Cursor uses .cursor/mcp.json. VS Code uses .vscode/mcp.json. Windsurf uses mcp_config.json in ~/.codeium/windsurf/. Zed embeds MCP config in its settings.json. The JSON structure is similar across clients but the root key and some fields differ.

Common setup issues

The most common MCP setup issues include: forgetting to restart the client after editing config, incorrect file paths in args, missing API keys in the env object, and using the wrong root key (VS Code uses 'servers' while most others use 'mcpServers', and Zed uses 'context_servers'). If a server fails to connect, check the client's MCP logs for specific error messages. Also ensure npx is in your PATH and Node.js is installed for npm-based servers.