Summary
It edits the file that decides what your other agent is allowed to do.
Roo's custom modes each carry a slug, a role definition, the tool groups they may use and their own instructions. Listing, reading and creating them through tool calls means the mode for a recurring job can be written in the conversation that revealed the need for it.
What it is
A server over Roo's custom modes configuration. It reads and writes a JSON file whose path you set, validating an entry against a schema before it lands.
What you get
- list_modes — the custom modes currently defined
- get_mode — one mode read back in full: its slug, name, role definition, the groups it may use, and its custom instructions
- create_mode — a new mode written, validated with Zod before the file changes
- File-system watching, so a configuration edited outside the server is picked up
- Atomic file writes, with errors returned as standard MCP error codes
Requirements
The path to your custom modes JSON file, set in the configuration — it defaults to Roo's own location under the editor's global storage. Node.js and a clone of the repository built with npm; there is no published package.