cairn-adopt-components

Skill: cairn-adopt-components

Host portability

This skill is shared by Claude Code, Cursor, and Codex. Use the host's structured question UI when available; otherwise ask the same concise A/B/C question in chat and pause. Named subagent briefs live under ../../agents/: dispatch by name where supported, or read the brief and pass it to the host's native subagent tool. Execute inline only when no subagent tool exists.

You are backfilling Cairn's component store into an already-adopted project — the one-time work the adoption pipeline does for fresh repos, applied to a repo that predates the store. The goal: every component file carries a @cairn registry header, the derived index is built, and @singleton headers become §INVs. Spec: docs/PLUGIN_ARCHITECTURE.md §6 (the component trio 9d→9e→9f) and docs/COMPONENT_STORE_PLAN.md.

This skill drives the bundled dist/cli.mjs internally using the plugin-root variable supplied by the active host (PLUGIN_ROOT, CURSOR_PLUGIN_ROOT, or CLAUDE_PLUGIN_ROOT). Never surface a CLI subcommand to the operator (Plugin spec §11) — the chat shows progress + consent gates, not commands.

Step 0 — classify the repo

Run this single probe to decide whether backfill applies. It is ghost-aware: a ghost-adopted repo has no in-repo .cairn/ — its state lives out-of-repo at ~/.cairn/state/<root-commit>/. The probe resolves the effective state home (in-repo when present, else the out-of-repo ghost dir keyed on the repo's root-commit) and prints <mode> <verdict> <home>:

node -e '
  const fs=require("node:fs");
  const os=require("node:os");
  const path=require("node:path");
  const cp=require("node:child_process");
  const root=process.cwd();
  let mode="committed";
  let home=path.join(root,".cairn");
  if(!fs.existsSync(home)){
    // No in-repo .cairn — may be ghost-adopted. Ghost state lives at
    // ~/.cairn/state/<repo-id>; repo-id is the move-stable root-commit SHA
    // (matches registerGhostRepo). Resolve it and probe there instead.
    let rc="";
    try{rc=cp.execFileSync("git",["-C",root,"rev-list","--max-parents=0","HEAD"],{encoding:"utf8",stdio:["ignore","pipe","ignore"]}).trim().split(/\s+/)[0]||"";}catch{}
    if(rc){const g=path.join(os.homedir(),".cairn","state",rc);if(fs.existsSync(g)){home=g;mode="ghost";}}
  }
  const cfg=path.join(home,"config.yaml");
  const idx=path.join(home,"ground","components");
  if(!fs.existsSync(home)||!fs.existsSync(cfg)){console.log(mode+" not-adopted "+home);process.exit(0);}
  let hasBlock=false;
  try{hasBlock=/^components:/m.test(fs.readFileSync(cfg,"utf8"));}catch{}
  const hasIndex=fs.existsSync(idx)&&fs.readdirSync(idx).length>0;
  console.log(mode+" "+(hasBlock&&hasIndex?"has-store":"backfill")+" "+home);'