# Skills, commands, and MCP servers

> Discover provider-native skills and commands, and how sessions get MCP tools.

Canonical URL: https://docs.zuse.sh/composer/skills-mcp



Zuse keeps provider-native extensions visible without inventing a second configuration format.

## Skills [#skills]

For Claude Code and Codex, the composer discovers global and project skills from the provider's native skill directories. Type `/` to search built-in commands and discovered skills. The list refreshes when relevant skill files change.

A selected skill is passed to the active provider with its name and arguments. Read a third-party skill before running it: skill instructions can ask the agent to use tools, access services, or modify files, and the session's permission posture still governs those actions.

Zuse also installs its own [bundled skill](/reference/bundled-skill.md) for configuration and troubleshooting help.

## Built-in commands [#built-in-commands]

Commands such as `/new`, `/model`, `/mode`, `/plan`, `/run`, and `/help` are handled by Zuse. The same picker can surface provider commands. Those commands are sent to the provider as written, so their exact behavior follows the installed provider version.

Only commands applicable to the active provider appear. Goal mode is exposed for supported Codex and Grok versions.

## MCP servers [#mcp-servers]

Agents launched by Zuse receive MCP tools only through Zuse's session gateway, which serves the plugins connected to your workspace. Zuse does not pass through MCP servers configured in a provider's own files, and stops each provider CLI from loading them where the CLI supports it.

To use another MCP server, add it in **Plugins**, either from the catalog or as a custom remote server. See [Add an MCP server](/how-to/local-configure-mcp.md).

Start a new chat after connecting a plugin. An existing provider process may still have its older tool set.