cross-repo-cache

Cross-Repo Cache Skill

Check whether prior cross-repo coordinator results are still valid, avoiding redundant Sonnet agent launches when peer repositories haven't changed.

When to Use

Activate this skill at the start of Phase 1.4.1 (Discover peers), before launching @code:cross-repo-coordinator. If the cache is fresh, skip the coordinator and use cached results.

Usage

The scripts/ directory is relative to this skill's base directory (shown above as "Base directory for this skill").

Check Cache (Phase 1.4.1)

bash <base_directory>/scripts/check_cross_repo_cache.sh <WORKDIR>

Stamp Cache (after coordinator completes)

After the cross-repo-coordinator runs successfully, stamp the cache:

# Compute hash of peer repo states
if [ -f ".workspace-repos.json" ]; then
  repo_hashes=""
  for repo_path in $(python3 -c "import json; [print(r['path']) for r in json.load(open('.workspace-repos.json')) if r.get('path')]" 2>/dev/null); do
    [ -d "$repo_path/.git" ] && repo_hashes="$repo_hashes$repo_path:$(git -C "$repo_path" rev-parse HEAD 2>/dev/null || echo unknown) "
  done
  echo "$repo_hashes" | shasum -a 256 > $WORKDIR/.cross-repo-hash
else
  shasum -a 256 $WORKDIR/.cross-repo-needs.json > $WORKDIR/.cross-repo-hash
fi

Interpreting Output

Cache Hit

CROSS_REPO_CACHE_HIT
status: NO_CROSS_REPO_NEEDED | CAPABILITIES_IDENTIFIED
capabilities:
  - peer-name: capability description

Action:

• If status is NO_CROSS_REPO_NEEDED: Mark 1.4.x phases complete, proceed to Phase 2
• If status is CAPABILITIES_IDENTIFIED: Skip coordinator, proceed to Phase 1.4.2 with cached capabilities

Cache Miss

CROSS_REPO_CACHE_MISS
reason: <why the cache is stale or missing>

Action: Launch @code:cross-repo-coordinator as normal. After it completes, stamp the cache.

How Freshness Works

The script hashes the git HEAD commit of each peer repository listed in .workspace-repos.json. If any peer has new commits, the hash changes and the coordinator re-runs. This correctly handles the case where a peer repo is updated between iterations.

Cache Location

• Coordinator results: $WORKDIR/.cross-repo-needs.json (written by coordinator)
• Cache hash: $WORKDIR/.cross-repo-hash (written by stamp step)
• Per-repo cache: .learnings/cross-repo-cache/{repo-name}/ (used by generic-discovery agents)