Add rtk

Install rtk — a CLI proxy delivering 60–90% token savings on common dev commands (git, cargo, pytest, docker, kubectl, etc.) — and wire it transparently into agent containers via the Claude Code PreToolUse hook.

What this sets up

• rtk binary at ~/.local/bin/rtk on the host
• ~/.local/bin/rtk mounted read-only at /usr/local/bin/rtk inside the target agent group's containers
• PreToolUse hook in the agent group's settings.json so every Bash call is automatically filtered through rtk — no CLAUDE.md instructions needed

Integration tests

This skill has no in-tree integration test by design. Its only functional reach-ins are runtime operator actions — the host-only ncl groups config add-mount (Step 3) and the settings.json PreToolUse hook write (Step 4) — neither of which leaves a line in the source tree whose deletion a test could catch. There are no package dependencies or Dockerfile edits to guard either. Conformance is idempotent apply + REMOVE.md; the mount and hook are verified at runtime (see Verify).

Step 1 — Install rtk on the host

curl -fsSL https://raw.githubusercontent.com/rtk-ai/rtk/refs/heads/master/install.sh | sh