autosync-ic-skills

Set up self-updating Internet Computer skills

This skill installs a small amount of project configuration so that every new Claude Code session automatically downloads the latest Internet Computer skills into .claude/skills/, where Claude discovers and triggers them natively.

It is a one-time installer. After you complete the steps below, the user never needs this link again — the installed SessionStart hook does the work from then on.

What you will create

1. .claude/sync-ic-skills.sh — a differential sync script that mirrors the live skill index into .claude/skills/.
2. A SessionStart hook in .claude/settings.json that runs that script.
3. An immediate first run, so skills are present right away.

The script is a differential mirror. It fetches the discovery index once and compares each skill's published hash against a stored manifest, re-downloading only the skills that actually changed (and pruning ones removed upstream). Unchanged skills are skipped with no per-file downloads, and the script writes nothing to stdout unless something changed. If the server does not publish a hash for a skill, the script falls back to re-downloading it every run, so it remains correct either way.

Important: tell the user what to expect

Adding a hook means a shell script will run automatically at the start of future sessions. Claude Code will ask the user to review and trust the new hook before it activates — this is expected and correct. Let the user know:

"I'm adding a SessionStart hook that runs .claude/sync-ic-skills.sh. Claude Code will ask you to approve/trust it before it runs automatically. After that, your IC skills stay current on every session."

Do not attempt to bypass that approval.

Step 0 — Check prerequisites (curl, jq)

The sync script needs curl (virtually always present) and jq (often not). Before writing anything, check for them:

command -v curl >/dev/null 2>&1 && echo "curl: ok" || echo "curl: MISSING"
command -v jq   >/dev/null 2>&1 && echo "jq: ok"   || echo "jq: MISSING"

• If jq is missing, offer to install it (ask the user before running an install command). Pick the right one for their platform:
  • macOS (Homebrew): brew install jq
  • Debian/Ubuntu: sudo apt-get update && sudo apt-get install -y jq
  • Fedora/RHEL: sudo dnf install -y jq
  • Alpine: apk add jq
  • Arch: sudo pacman -S --noconfirm jq
  • Windows (winget): winget install jqlang.jq
• If the user declines, still proceed — the script is written to degrade gracefully (it exits cleanly with a warning when jq is absent), and they can install jq later and the next session will sync.

Step 1 — Download the sync script

The script is published as a file alongside this skill, so you fetch it verbatim rather than transcribing it (this guarantees byte-exact content). Create the .claude directory and download it:

mkdir -p .claude
curl -fsSL https://skills.internetcomputer.org/.well-known/skills/autosync-ic-skills/scripts/sync-ic-skills.sh \
  -o .claude/sync-ic-skills.sh

Do not hand-write or paraphrase the script — always fetch the published copy so the sync logic stays correct as it is updated upstream.

What the script does (for the user's awareness):

• Fetches https://skills.internetcomputer.org/.well-known/skills/index.json once.
• For each skill, compares the published hash against .claude/skills/.ic-managed.json (a { "<skill>": "<hash>" } manifest of skills it manages) and re-downloads only the skills whose hash changed or are new.
• Prunes skills it previously installed that are no longer in the index, and replaces a changed skill's whole directory via an atomic staging swap — so files renamed or removed upstream don't linger inside a skill, and an interrupted download leaves the existing copy intact.
• Writes nothing to stdout on a no-op sync. When something changed it prints one JSON object whose systemMessage carries the added / updated / removed summary — that string is what the user sees, because SessionStart hooks surface JSON fields rather than raw output. Its diagnostics (interrupted-sync recovery, unsafe skill names) go to stderr and so are not displayed.
• Degrades gracefully: exits cleanly (keeping cached skills) if the network is down or jq is missing, and falls back to re-downloading skills the server publishes no hash for.

Step 2 — Register the SessionStart hook (idempotently)

Add a SessionStart hook to .claude/settings.json that runs the script.

• If .claude/settings.json does not exist, create it with the content below.
• If it does exist, merge — preserve all existing keys, hooks, and permissions. Only add the SessionStart entry, and only if an equivalent bash .claude/sync-ic-skills.sh command is not already present (do not create a duplicate). Parse the existing JSON, insert into the hooks.SessionStart array, and write it back; never blindly overwrite the file.

The entry to ensure is present:

{
  "hooks": {
    "SessionStart": [
      {
        "hooks": [
          { "type": "command", "command": "bash .claude/sync-ic-skills.sh" }
        ]
      }
    ]
  }
}

Step 3 — Run it once now

Run the script immediately so the skills are available in this session without waiting for the next session start:

bash .claude/sync-ic-skills.sh

Step 4 — Verify and report

• Confirm .claude/skills/ now contains skill directories (e.g. writing-motoko, static-site, internet-identity, …) each with a SKILL.md.
• Confirm .claude/skills/.ic-managed.json maps each synced skill name to its hash.
• Tell the user: how many skills were installed, that the SessionStart hook is in place, and that they'll be prompted to trust the hook before it auto-runs next session. From then on, their IC skills refresh automatically every session.

Notes

• Safe to re-run. Re-invoking this skill or the script is idempotent: the hook is not duplicated, and only skills tracked in .ic-managed.json are ever pruned.
• Differential by hash. The script keys off the per-skill hash field in the discovery index, so a normal session that touches nothing downloads only index.json and exits silently. Skills are re-downloaded only when their hash changes. Migrating from an older version of this script (whose manifest was a bare name array) is handled automatically on the next run.
• Optional mid-session refresh. For very long-running sessions, the user can also run bash .claude/sync-ic-skills.sh manually, or schedule it (e.g. via /loop or a cron routine) — but the SessionStart hook covers the normal case.