# Ruby MCP topics

Source: https://libtmux.org/en/ruby/v0.1.0.alpha.2/mcp/topics/

> Understand tool policy, retained observations, resources, and authored runs.

**MCP concept example** Maintained as a working example of core library usage and deployment. Example APIs, tools and configuration may change without a compatibility or product support commitment.

The Ruby MCP server exposes selected operations on one tmux endpoint.
Its tool policy controls what clients can request; captured metadata and
references determine what those requests describe.

## Tool policy

[`tmux_capabilities`](<https://libtmux.org/en/ruby/v0.1.0.alpha.2/mcp/tools/tmux_capabilities/>) and [`tmux_snapshot`](<https://libtmux.org/en/ruby/v0.1.0.alpha.2/mcp/tools/tmux_snapshot/>) are enabled by default. Capture, wait,
create, send, close, and run tools remain absent until the process receives a
matching `--enable-tool` option. Direct application calls enforce the same
policy as protocol discovery.

## Captures and resources

Snapshots and screen captures retain immutable observations. A cursor pages
that retained state; it does not silently substitute a newer live listing.
Resource templates expose metadata pages and pane screens using encoded
endpoint and generation identities. The server advertises neither resource
subscriptions nor resource-list change notifications, and it has no prompt
catalog.

## Authored runs

[`tmux_run`](<https://libtmux.org/en/ruby/v0.1.0.alpha.2/mcp/tools/tmux_run/>) needs both `--enable-tool tmux_run` and an exact
`--enroll-pane %ID=FILE` entry. The operator must source the generated file in
that pane's interactive zsh 5.9. Enrollment does not type into the terminal,
and a later pane respawn cannot redirect an authorized request to the
replacement process.

The tool reports stdout and stderr independently. Nonzero exits and signals
are completion results; overflow is an error, not truncated success.

[Source-owned policy and enrollment guide](https://libtmux.org/en/ruby/v0.1.0.alpha.2/mcp/source-guide/)

- [Snapshots and references](https://libtmux.org/en/ruby/v0.1.0.alpha.2/mcp/topics/snapshots-and-references/): Filter metadata, continue a retained result, and handle expired cursors and stale references.