What is the mcpServers config?
The mcpServers config is the JSON block, used by Claude Desktop, Cursor, Cline, and others, that registers MCP servers with a client by naming each one and giving its command, args, env, or URL.
Most MCP clients are configured through a JSON object whose top-level key is mcpServers. Each entry is a named server: for a local server you provide a command (such as npx or uvx), an args array, and optionally an env map for secrets like API keys; for a remote server you provide a url and, depending on the client, a type and headers for auth. The exact file and key vary by client. Claude Desktop, Cursor, and Cline use mcpServers; VS Code uses a servers key; Zed nests servers under context_servers; and Codex uses TOML instead of JSON. Getting this block exactly right is the whole game for a working setup, which is why a single wrong package name or missing flag breaks the connection. Directories that publish copy-paste-correct mcpServers snippets per client save the most common source of MCP setup pain.