Config Sync

/configure:config-sync

Extract, compare, and propagate tooling config improvements across FVH repos.

When to Use This Skill

Context

• Workspace root: /Users/lgates/repos/ForumViriumHelsinki
• Repos: !fd -t d -d 1 . /Users/lgates/repos/ForumViriumHelsinki --exclude .git --exclude node_modules
• Current directory: !pwd

Parameters

Parse mode and options from command arguments:

Modes

1. extract [repo-name] — Identify improvements in a source repo
2. diff <file-pattern> — Compare a specific config across all repos
3. apply <file-pattern> [--from repo] [--to repo1,repo2,...|--all] — Propagate config to targets

Options

• --from <repo> — Source repo for apply mode (default: best version detected)
• --to <repo1,repo2,...> — Target repos (comma-separated)
• --all — Target all repos that have the file
• --dry-run — Show what would change without creating branches/PRs (default behavior)
• --confirm — Actually create branches and PRs

Config Categories

Files tracked for cross-repo sync, organized by sync strategy:

Tier 1: Wholesale (100% identical across repos)

Copy verbatim — no repo-specific variations expected.

Tier 2: Parameterized (shared core with known variation points)

Shared structure with specific fields that vary per repo.

Tier 3: Structural (standard skeleton, project-specific bodies)

Standard recipe/section names must conform; bodies are project-specific.

Tier 4: Pattern-based (categorized by tech stack)

Group by detected stack, extract general best practices only.

Tier 5: Reference (compare and report, selective apply)

Execution

Extract Mode

Goal: Scan a repo and identify improvements that could benefit other repos.

Step 1: Identify the source repo

If repo name provided, use /Users/lgates/repos/ForumViriumHelsinki/<repo-name>. Otherwise use the current working directory (must be inside an FVH repo).

Step 2: Scan tooling files

Scan for all tracked config categories:

fd -t f -d 3 '(claude|renovate|auto-merge|release-please|container-build|Dockerfile|justfile|skaffold)' <repo-path>

Also check:

• .github/workflows/*.yml
• justfile
• Dockerfile*
• renovate.json
• release-please-config.json
• .release-please-manifest.json
• skaffold.yaml

Step 3: Compare against workspace patterns

For each file found:

1. Wholesale tier: Hash the file content and compare against the most common version across all repos. Report if this repo has a newer/different version.
2. Parameterized tier: Extract the shared core (strip known variation points) and compare structure.
3. Structural tier (justfile): Check for standard recipes (default, help, dev, build, clean, lint, format, format-check, test, pre-commit, ci). Report missing standard recipes and non-standard names (e.g., check instead of lint).
4. Pattern-based tier: Detect tech stack, then check for best practices:
   • Pinned base images (not latest)
   • .dockerignore present
   • Multi-stage builds
   • Non-root user
   • SHA-pinned GitHub Actions
   • SBOM/provenance attestation
5. Reference tier: Note divergences from the most common configuration.

Step 4: Generate extract report

Config Extract Report: <repo-name>
====================================

Wholesale Configs:
  claude.yml       ✅ Matches canonical (sha: abc123)
  renovate.json    ⚠️  Differs from canonical — newer features detected

Parameterized Configs:
  auto-merge-image-updater.yml  ✅ Core matches, variation: branch-prefix=argocd
  release-please.yml            ⚠️  Has publish job (novel improvement)

Structural (Justfile):
  Standard recipes: 8/11 present
  Missing: format-check, pre-commit, ci
  Non-standard names: none

Pattern-based (Dockerfile):
  Stack: Python
  ✅ Pinned base image (python:3.12-slim)
  ✅ Multi-stage build
  ⚠️  Missing .dockerignore
  ✅ Non-root user

Potential Improvements to Propagate:
  1. renovate.json — has newer schedule config
  2. release-please.yml — publish job pattern

Diff Mode

Goal: Compare a specific file across all FVH repos.

Step 1: Resolve file pattern

Interpret the file pattern argument:

• Full path: .github/workflows/claude.yml
• Short name: claude.yml → search in .github/workflows/
• Glob: *.yml → match all workflows

Step 2: Find the file across repos

fd -t f '<pattern>' /Users/lgates/repos/ForumViriumHelsinki --max-depth 4

Step 3: Group by content hash

For each found file, compute a content hash:

shasum -a 256 <file>

Group files by identical hash. Sort groups by size (largest first = most common version).

Step 4: Identify the "best" version

Heuristics for selecting the canonical version:

1. Most common hash (majority rules)
2. If tie: most recently modified
3. If tie: from infrastructure repo (reference repo)

Step 5: Generate diff report

Config Diff: .github/workflows/claude.yml
==========================================

Group 1 (canonical) — 18 repos [sha: abc123]:
  citylogger, CycleRoutePlanner, FVHIoT-python, ...

Group 2 — 2 repos [sha: def456]:
  theme-management, OLMap
  Differences from canonical:
    - Line 12: uses different action version
    - Line 25: extra step for Node setup

Not present in (5 repos):
  infrastructure, helm-webapp, terraform-modules, ...

Recommendation: Update Group 2 repos to match canonical.

For small files (< 100 lines), show an inline unified diff between the canonical and each outlier group.

Apply Mode

Goal: Propagate a config file from source to target repos.

Step 1: Determine source

• If --from specified, use that repo's version
• Otherwise, run diff mode internally to find the canonical version

Step 2: Determine targets

• If --to specified, use those repos
• If --all, use all repos that currently have the file (excluding source)
• Otherwise, ask the user which repos to target

Step 3: Determine sync strategy by tier

Wholesale: Copy file verbatim to targets.

Parameterized: Copy file but preserve known variation points:

• auto-merge-image-updater.yml: preserve BRANCH_PREFIX value
• release-please.yml: preserve extra publish/deploy jobs

Structural (justfile): Do NOT overwrite. Instead:

• Add missing standard recipe stubs (commented templates)
• Suggest renaming non-conforming recipes
• Preserve all project-specific recipes and recipe bodies

Pattern-based: Only apply general improvements matching the target's stack:

• Pin unpinned base images
• Add missing .dockerignore
• Update SHA-pinned actions
• Do NOT change build args, multi-arch config, or app-specific steps

Reference: Show diff and ask user to confirm each change.

Step 4: Preview changes (default / --dry-run)

For each target repo, show the unified diff of what would change.

Dry Run: Apply .github/workflows/claude.yml
============================================

repo: OLMap
  Status: Will update (sha def456 → abc123)
  Diff:
    @@ -12,1 +12,1 @@
    -    uses: actions/checkout@v3
    +    uses: actions/checkout@v4

repo: theme-management
  Status: Will update (sha def456 → abc123)
  Diff: (same as above)

Total: 2 repos would be updated

Step 5: Execute changes (--confirm or user approval)

For each target repo:

1. Create a branch: config-sync/<filename-slug>
2. Copy/update the file
3. Commit with conventional message: chore: sync <filename> from <source-repo>
4. Push and create PR via gh pr create

cd /Users/lgates/repos/ForumViriumHelsinki/<target-repo>
git checkout -b config-sync/claude-yml
# ... apply changes ...
git add <file>
git commit -m "chore: sync claude.yml from canonical

Co-Authored-By: Claude <noreply@anthropic.com>"
git push -u origin config-sync/claude-yml
gh pr create --title "chore: sync claude.yml" --body "$(cat <<'EOF'
## Summary
- Synced `.github/workflows/claude.yml` to match canonical version
- Source: most common version across 18 repos

## Changes
<inline diff>

🤖 Generated with [Claude Code](https://claude.com/claude-code)
EOF
)"

**Inside a quoted heredoc (<<'EOF'), backticks, $, and \ are already literal — never backslash-escape them.** A stray \`` lands in the rendered PR body and needs a follow-up gh pr editto fix. To skip the$(cat ...)subshell entirely, feed the body straight togh` over stdin:

gh pr create --title "chore: sync claude.yml" --body-file - <<'EOF'
## Summary
- Synced `.github/workflows/claude.yml` to match canonical version
EOF

Report results:

Apply Results:
  OLMap: PR #42 created — https://github.com/ForumViriumHelsinki/OLMap/pull/42
  theme-management: PR #15 created — https://github.com/ForumViriumHelsinki/theme-management/pull/15

Agentic Optimizations

Safety

• Dry-run by default: apply only shows diffs unless --confirm is passed or user explicitly approves
• Never overwrites justfile recipe bodies: Only adds stubs and suggests renames
• Stack-aware Dockerfile sync: Only applies improvements matching the target's tech stack
• Preserves parameterized variation points: Known customizations are not overwritten

See Also

• /configure:workflows — Single-repo workflow compliance
• /configure:reusable-workflows — Install reusable workflow patterns
• /configure:justfile — Single-repo justfile compliance
• /configure:dockerfile — Single-repo Dockerfile compliance
• /configure:all — Run all compliance checks on current repo