Resync Research and Learning pack sources into ~/.pai/skills/ runtime

[virtualian]

Context

During the 2026-04-20 skill-migration run (#110 artefact, engine/skill-migration.ts) on the maintainer's local laptop, drift backups on Research and Learning surfaced a three-stale-copies situation:

Copy	Path convention	Voice pattern
Canonical winner (~/.claude/skills/<Pack>, mtime 19-24 Mar)	~/.claude/MEMORY/... literals	"Workflow Announcement" (text-only)
Displaced backup (~/.pai/skills/<Pack>, mtime 7-15 Apr)	${PAI_DIR}/MEMORY/... tokens (post-#114)	bun ~/.claude/PAI/Tools/Notify.ts ... invocations
Repo source (Packs/<Pack>/src/, authoritative)	${PAI_DIR}/MEMORY/... tokens	bun ~/.pai/PAI/Tools/Notify.ts ... invocations (two-root-aware)

Skill-migration's "CC side wins on drift" rule chose the most stale of the three — an under-specified input to the rule, not a bug in the rule itself.

Problem

There is no authoritative sync path from Packs/<Pack>/src/ into ~/.pai/skills/<Pack>/ for upgraders. Pack sources evolve in the repo (#114 path sweep, post-#112 voice-path updates, ongoing content edits), but the runtime ~/.pai/skills/ tree only receives updates when some ad-hoc process happens to run.

Symptoms on this laptop:

• Research: SKILL.md + three workflow files lag repo source by ≥5 weeks.
• Learning: SKILL.md + three workflow files + one tool file lag repo source. Notify.ts invocation paths point at ~/.claude/PAI/Tools/ instead of ~/.pai/PAI/Tools/.
• Every other pack that showed drift in the migration is likely similar, but Research and Learning are the confirmed cases.

Drift backups containing the less-stale intermediate copy have been discarded; canonical is now ~/.pai/skills/<Pack> but still lags repo source.

Scope

Mechanism to bring ~/.pai/skills/<Pack> into alignment with Packs/<Pack>/src/ for PAI-owned packs, on upgrade runs. Candidate approaches (investigation, non-exhaustive):

1. Per-pack install/upgrade wizard that copies Packs/<Pack>/src/ → ~/.pai/skills/<Pack>/, with conflict detection against runtime-local edits.
2. Peer of engine/skill-migration.ts that treats Packs/<Pack>/src/ as the authority when both runtime copies are older than source.
3. Sync tool that operates outside the installer, invoked explicitly on demand.
4. Something else the investigation surfaces.

Acceptance

• Running a resync on a laptop brings ~/.pai/skills/<Pack>/ into alignment with current Packs/<Pack>/src/ for PAI-owned packs.
• User-level runtime edits (if any exist) are detected and preserved, not silently overwritten.
• Idempotent — safe to re-run. Soft-fail per pack if one fails.
• Produces backups before overwriting, same pattern as Skills separation is documentation-only: Claude Code harness reads ~/.claude/skills/, not ~/.pai/skills/ #110's migration.

Related

• Skills separation is documentation-only: Claude Code harness reads ~/.claude/skills/, not ~/.pai/skills/ #110 — skill canonicalisation (closed); "CC side wins" rule is correct but produces stale outcomes when source is newer than both runtime copies.
• Slash commands forgotten by two-root architecture: no ~/.pai/commands/, installer never sees them, /cs missing on disk #113 — commands canonicalisation, has the same chicken-and-egg: ~/.pai/commands/ never populated because no pack-level staging path.
• Sweep: 433+ stale ~/.claude/ doc-text refs across ~/.pai/skills/ and ~/.pai/agents/ markdown #114 — the path-token sweep whose updates didn't propagate to runtime.
• Investigate: restructure two-root split to simplify absorbing upstream releases #144 — upstream-absorption investigation; this issue is a concrete instance of the multi-copy drift hazard Investigate: restructure two-root split to simplify absorbing upstream releases #144 describes.

Out of scope

• Implementation. Investigation and design recommendation.
• Third-party pack sync (out of scope for PAI install infrastructure).