sn-update

Refresh installed sn-* skills from upstream SenseNova-Skills.

Decide the scope

• No list given → every sn-* skill upstream.
• Specific skills named → only those. Don't expand.
• A named skill missing upstream → surface as error and stop.
• User said "force / 强制" → re-install even when up-to-date.

Decide the target agent

Check which directories exist:

Sync the upstream repo

Persistent cache at ~/.cache/sn-update/repo/. Default URL: https://github.com/OpenSenseNova/SenseNova-Skills.git. User may override with a fork URL.

• First run: if you want to actually limit blob download, use partial clone with --filter=blob:none --no-checkout, then sparse-checkout only the selected skills/<name> paths before copying them. --filter=blob:none alone does not keep the cache small if the full worktree is checked out; that checkout will still download most or all needed blobs. It still preserves history metadata for SHA queries.
• Subsequent runs: fetch + hard-reset to the upstream default branch, and re-apply sparse-checkout for only the requested skills/<name> paths before copying. If updating the whole sn-* bundle, expect most/all skill blobs to be downloaded.
• URL changed: if cache's origin differs from the requested URL, delete and re-clone.

Compare versions per skill (A → B → C)

For each skill, pick the highest-precedence signal present on both sides (installed + upstream); equal → skip, differ → install.

Upstream "version" is the per-subtree commit SHA — using repo HEAD would mark unrelated skills as stale every time:

git -C <cache> log -1 --format=%H -- skills/<skill-name>

• A — .sn-version marker: one-line file inside the installed skill holding the SHA from its last install.
• B — .sn-release marker (fallback): one-line file holding the upstream tag name. Compare against git describe --tags --abbrev=0.
• C — optional version: field in SKILL.md frontmatter: parse from YAML on both sides, but only for forks or skills that explicitly add this field. If either side lacks it, C does not apply.
• Nothing usable → treat as stale and install.

Always write .sn-version on install so future runs can use A.

Install with backup

For each skill flagged "install":

1. Move (not copy) any existing <agent-skills>/<skill-name>/ into a single timestamped backup bucket shared by all skills in this run: ~/.<agent>/skills_backup/<UTC-timestamp>/<skill-name>/ (e.g. 2026-04-30T15-29-07Z).
2. Copy <cache>/skills/<skill-name>/ → <agent-skills>/<skill-name>/. Never symlink (ln -s) from the cache. The cache lives under ~/.cache/ with permissions the agent runtime may not be able to traverse, and some runtimes refuse to load skills resolved through symlinks. Always do a real recursive copy so the installed tree is self-contained and owned by the agent skills dir.
3. Write .sn-version with the upstream subtree SHA inside the new copy.

If the bucket ends up empty (all targets were fresh installs), remove it.

The backup tree is a sibling of skills/, never a .bak folder inside it — most agent runtimes scan the whole skills/ directory and would pick up stale duplicates.

Enforce backup retention

After every run, prune the per-agent backup root to at most 3 buckets. Timestamps sort lexicographically; keep the newest 3, delete the rest. Run this even when the current run produced no backup of its own.

Report to the user

Group by status, keep it short:

Updated (3): sn-ppt-standard, sn-image-base, sn-deep-research
Already up-to-date (5): sn-ppt-creative, sn-ppt-doctor, ...
Backup: ~/.openclaw/skills_backup/2026-04-30T15-29-07Z/

• Omit Backup: when nothing was backed up.
• Show SHA pairs (abc1234 → def5678) only if the user asks for detail.
• Errors get their own line — never bury them in a success summary.

Edge cases

• Asks to delete sn- skills* — not this skill's job. Decline; point at ~/.<agent>/skills_backup/ if they want to roll back.
• User is in the dev repo and asks to "update sn skills" — they mean push to their agent install. Proceed normally; this skill only touches the cache and the agent install dirs, never the dev checkout.
• sn-update updating itself — fine; the new copy takes effect on the next invocation.