add-rtk skill

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

If the script put the binary elsewhere, move it:

find ~/.local ~/.cargo/bin ~/bin -name rtk 2>/dev/null
mv "$(which rtk 2>/dev/null)" ~/.local/bin/rtk

Verify:

~/.local/bin/rtk --version
chmod +x ~/.local/bin/rtk   # if needed

Step 2 — Identify the target agent group

ncl groups list

Note the group ID (e.g. ag-1776342942165-ptgddd). Repeat Steps 3–5 for each group.

Step 3 — Mount rtk into the container config

Mount the host rtk binary read-only into the container with the host-only add-mount verb. It is idempotent — re-running skips the entry if it is already present:

ncl groups config add-mount --id <group-id> \
  --host ~/.local/bin/rtk \
  --container /usr/local/bin/rtk \
  --ro

This verb is operator-only and runs host-side (via /setup, /customize, or /manage-mounts); it is rejected from inside a container.

The host root (~/.local/bin) must also be in the external mount allowlist at ~/.config/nanoclaw/mount-allowlist.json for the mount to take effect at spawn. Add it there if it isn't already.

Verify:

ncl groups config get --id <group-id>
# Look for the /usr/local/bin/rtk mount

Step 4 — Add the PreToolUse hook to settings.json

Each agent group has a settings.json at:

data/v2-sessions/<group-id>/.claude-shared/settings.json

This file is mounted at /home/node/.claude/settings.json inside the container and is read by Claude Code for hooks, env, and model config.

Add the PreToolUse entry with jq. This drops any existing rtk Bash hook first, then appends a fresh one, so it is safe to re-run without creating duplicates:

SETTINGS="data/v2-sessions/<group-id>/.claude-shared/settings.json"

jq '.hooks.PreToolUse = ((.hooks.PreToolUse // [])
      | map(select((.hooks // []) | any(.command == "rtk hook claude") | not)))
    + [{"matcher":"Bash","hooks":[{"type":"command","command":"rtk hook claude"}]}]' \
  "$SETTINGS" > /tmp/rtk-settings.json && mv /tmp/rtk-settings.json "$SETTINGS"

Step 5 — Restart the container

ncl groups restart --id <group-id>

Verify

Confirm the binary is executable inside the container so a missing or non-executable mount surfaces immediately rather than as a silent hook failure:

docker exec "$(docker ps --filter "name=<group-id>" --format '{{.Names}}' | head -1)" rtk --version

Then ask the agent to run git status or any other supported command. rtk intercepts it silently. Check savings with:

~/.local/bin/rtk gain

Troubleshooting

rtk: command not found inside the container

Mount wasn't applied or container wasn't restarted:

ncl groups config get --id <group-id>
# Look for the /usr/local/bin/rtk mount
ncl groups restart --id <group-id>

Hook not firing

Verify the hook is in settings.json:

jq '.hooks.PreToolUse' data/v2-sessions/<group-id>/.claude-shared/settings.json

If missing, re-run Step 4.

Binary won't execute — permission denied

chmod +x ~/.local/bin/rtk