Then build an eval sweep that runs one prompt across every coding agent on
this machine.

libtmux drives a real tmux server from code. It gives you objects for the
server, its sessions, windows and panes. Documentation for every language
is at https://libtmux.org/en/.

Language:   Ruby
Package:    libtmux (RubyGems)
Repository: https://github.com/libtmux/libtmux-ruby

Read these before writing code:
- https://libtmux.org/en/ruby/latest/llms.txt
  every page for Ruby, as a list
- https://libtmux.org/en/ruby/latest/docs.json
  the same list with headings, as JSON
- https://libtmux.org/en/ruby/latest/reference/
  the Ruby API reference
If you cannot fetch URLs, clone the repository above and read its README
and examples instead, or ask me to paste those pages in.

Set up first:
1. Report the tmux version with `tmux -V`. libtmux drives a real tmux, so
   nothing below works without one. Stop and tell me if it is missing.
2. If this directory is not a Ruby project yet, start one:
       bundle init
   Skip this in a project that already exists, and match what is here.
3. Add the dependency. libtmux has no stable release. 0.1.0.alpha.1 is the
   newest prerelease on RubyGems, and the command below names it because the
   resolver skips prereleases otherwise.
       bundle add libtmux --version 0.1.0.alpha.1
   Check https://rubygems.org/gems/libtmux for a newer version, and prefer a
   stable release over this one if there now is any.
4. Write the smallest program that proves the install works: connect to a
   tmux server, create a session, confirm it is there, then kill it. Give
   that server a socket of its own rather than using the default one, so
   this never touches a tmux I am already running. Run it, and show me the
   output and the files you added.

Rules for everything below:
- Use the reference above rather than guessing names. The ten libtmux
  ports do not share spellings, and a name from another language will look
  plausible and not exist.
- If the reference does not have something you expected, say so instead of
  writing a call that does not exist.
- Follow the conventions already in this repository.

Eval sweep

What it does:
- Finds which agent CLIs are actually on PATH and reports the ones it found,
  rather than assuming a fixed list.
- Runs the same prompt through each of them at the same time, one pane each,
  in a session I can attach to and watch.
- Captures each pane's full transcript to its own file, with the agent name,
  the prompt, and how long the run took.
- Prints a comparison at the end: who answered, who failed, who was slowest.

Constraints:
- Capture the whole transcript, including what scrolled past. A pane's visible
  area is not the run.
- Record wall-clock time per agent from the same clock, so the numbers compare.
- One agent hanging must not stall the sweep. Give each a deadline and record a
  timeout as a result rather than as a crash.
- Do not send my prompt anywhere except the agents I asked for.

Anchor it in these pages:
- https://libtmux.org/en/tmux/guides/capturing-output/       capturing output
- https://libtmux.org/en/tmux/concepts/queries/              queries
- https://libtmux.org/en/tmux/examples/capture-pane-output/  capture pane output