cairn-bootstrap

Skill: cairn-bootstrap

You are bootstrapping a freshly-cloned repo so this developer's local git hooks point at cairn's per-clone tooling. Bootstrap is per-clone, one-time, and silent — once finished, every commit on this machine attests through cairn's pre-commit / commit-msg / post-commit hooks.

Refer to docs/PLUGIN_ARCHITECTURE.md §17 Layer 4 for the full bootstrap-banner contract.

Trigger gate

Before doing anything, verify the SessionStart context included the bootstrap_required warning. If not, exit with no output. The skill is only meaningful when the SessionStart banner explicitly invited it.

Step 1 — surface the inline prompt

Render exactly:

This project uses Cairn, but your clone isn't bootstrapped yet. [a] bootstrap now (~5s) [b] skip — write surface disabled

Use AskUserQuestion. Do not preamble; the question is the entire turn.

• [a] → continue to Step 2.
• [b] → end the turn. The MCP write tools will continue to refuse with BOOTSTRAP_REQUIRED; the operator can re-trigger this skill from the next session's banner.

Step 2 — run the bundled join command

Spawn this Bash command in the repo's working directory:

node "${CLAUDE_PLUGIN_ROOT}/dist/cli.mjs" join

${CLAUDE_PLUGIN_ROOT} resolves to the plugin's cache dir at runtime; the bundle is self-contained, so there's no npm install -g or npx involved.

Expected stdout pattern:

cairn join: bootstrapped
  ✓ git hooks → .cairn/git-hooks
  ✓ post-merge cleanup wired

Per-step warnings are non-fatal (e.g. "no .cairn/git-hooks/ — re-run init"). Surface the full stdout in a fenced text block so the operator can review.

Step 3 — confirm + exit

When the subprocess exits 0:

Bootstrap complete. Cairn's write surface is unblocked for this clone; commits will attest automatically.

When it exits non-zero, surface the failure inline:

Bootstrap failed at step . [a] retry [b] abort + open .cairn/JOIN.md for manual recovery

Hard rules

• Never run cairn join via npx or a globally-installed CLI — the plugin owns the bundle path; using anything else risks version divergence between the plugin and the join logic.
• Never mention CLI commands like cairn join / cairn doctor / npx ... in operator-facing chat output. The skill is the surface; the bundle is the implementation.
• Bootstrap is per-clone. Re-running on a clone that's already bootstrapped is a no-op (the join command is idempotent).
• Caveman-ultra style for chat replies; full English in any code or document the skill writes.