MCP servers can live at different scopes - just this session, just this project, all your projects, or bundled in a plugin - and the scope determines who and what sees them.

What it does

Local scope loads a server for a single session. Project scope commits it to the repo so everyone on the team gets it. User scope lives in your home config and follows you across repos. Plugin scope bundles MCP as part of a distributable plugin. Claude Code resolves scopes in a predictable order so overrides work intuitively.

When to use it

Project scope for team-wide integrations (CI, internal APIs).
User scope for personal tools (your notes system, your calendar).
Local scope for quick experiments.
Plugin scope when shipping reusable MCP + skills bundles.

Gotchas

Project-scoped MCP config commits to the repo. Don't put secrets in it - use env var references.
Conflicting scopes resolve by precedence. Read the doc if unexpected tools are loading.
Plugin-scoped MCP may conflict with project-scoped ones. Namespace your tool names.

Official docs: https://code.claude.com/docs/en/mcp.md#mcp-installation-scopes