MCP Command¶

The mcp command exposes your CLI tool's functionality to AI agents using the Model Context Protocol (MCP).

Usage¶

mytool mcp [subcommand] [flags]

Description¶

Serves your CLI's commands to AI assistants (Claude, Cursor, VS Code and any MCP client) as tools, exports the catalogue, and registers the server with an editor. Every call runs the command as a subprocess of the same binary.

By default the server publishes compactly: a client lists three discovery tools (search_tools, get_tool_details, call_tool) and finds the command it needs through them. gtb set mcp.mode direct publishes one native tool per command instead. See AI Agents & MCP.

Subcommands¶

`mcp start`¶

Serves over standard input and output. Logs go to standard error.

mytool mcp start [--log-level debug|info|warn|error]

`mcp stream`¶

Serves the same tools over a Streamable HTTP endpoint, under the estate's controls lifecycle: interrupting the process drains active calls and cleans up running commands within the shutdown budget.

mytool mcp stream [--host <host>] [--port <port>] [--origin <origin>]... [--log-level <level>]

Flag	Default	Description
`--host`	all interfaces	Interface to bind
`--port`	`8080`	Port to serve on
`--origin`	none	A browser origin to trust besides the server's own (repeatable). Any other browser origin is refused with 403; clients that are not browsers send no `Origin`.
`--log-level`		Log level

Use mcp start for editor and desktop integrations that launch your tool as a subprocess; use mcp stream for a client that connects to a running endpoint.

`mcp tools`¶

Writes the full authorised catalogue as JSON.

mytool mcp tools [--output mcp-tools.json]

Each entry carries name, title, description, inputSchema, outputSchema and annotations. It is an offline export of what a client could discover; in compact mode the wire still publishes the three discovery tools. Use it to confirm which commands a build exposes and what a client is told about each.

`mcp claude`, `mcp cursor`, `mcp vscode`¶

Register the server with an editor:

mytool mcp vscode enable [--workspace] [--config-path <file>] [--server-name <name>] [--log-level <level>] [--env KEY=value]...
mytool mcp vscode disable [--workspace] [--config-path <file>] [--server-name <name>]
mytool mcp vscode list [--workspace] [--config-path <file>]

enable writes an entry pointing at this binary's mcp start into the editor's MCP configuration (Claude Desktop's claude_desktop_config.json, ~/.cursor/mcp.json, VS Code's user mcp.json; --workspace uses the project's .cursor/mcp.json or .vscode/mcp.json). Other entries are preserved, running it again replaces this entry only, disable removes it, and a file that is not valid JSON is refused untouched.

Gating sensitive commands¶

Every command in the tree is on the MCP tool surface by default. A command that should stay runnable on the CLI but not be callable by an agent is excluded at build time:

setup.ExcludeFromMCP(mycmd.NewCmdDeploy(props))

Exclusion is inherited: descendants of an excluded command are excluded too, unless one of them opts back in.

setup.IncludeInMCP(mycmd.NewCmdDeployStatus(props))

IsExposedToMCP walks a command and its ancestors and takes the nearest explicit decision: exposed wins for that command, excluded hides the subtree, and a tree with no decision anywhere is exposed.

The generator carries the same tri-state through .gtb/manifest.yaml:

gtb generate command -n post --mcp-enabled=false

Omitting the flag leaves the decision unset (inherit); --mcp-enabled=true records an explicit exposure, which is how you re-expose one subcommand of an excluded parent.

Exposure is build-time only¶

There is no configuration key or flag that changes the MCP surface at runtime. The decision is baked into the binary as a cobra annotation (gtb.mcp.exposure), so the surface a shipped binary presents is fixed and auditable. An operator cannot widen it, and a compromised config file cannot either.

Confirm what a given build actually exposes with mytool mcp tools, which writes the full tool definitions to mcp-tools.json. A pure command group is never exposed, whatever the markers say: it has nothing to run.