CODEOWNERS Management Skill

Analyze and audit CODEOWNERS files across repositories for coverage, consistency, and review efficiency.

MANDATORY: Discovery-First Pattern

Always locate CODEOWNERS files and list teams before analyzing ownership.

Phase 1: Discovery

#!/bin/bash

GH_API="https://api.github.com"

gh_api() {
    curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
         -H "Accept: application/vnd.github+json" \
         "${GH_API}/${1}"
}

echo "=== Locate CODEOWNERS Files ==="
gh_api "orgs/${GITHUB_ORG}/repos?per_page=20&sort=updated" | jq -r '.[].full_name' | while read repo; do
    for path in ".github/CODEOWNERS" "CODEOWNERS" "docs/CODEOWNERS"; do
        RESULT=$(gh_api "repos/${repo}/contents/${path}" 2>/dev/null)
        if echo "$RESULT" | jq -e '.name' >/dev/null 2>&1; then
            echo -e "${repo}\t${path}\tFOUND"
            break
        fi
    done
done | column -t | head -20

echo ""
echo "=== Organization Teams ==="
gh_api "orgs/${GITHUB_ORG}/teams?per_page=30" | jq -r '
    .[] |
    "\(.slug)\t\(.members_count // "?")\t\(.privacy)"
' | column -t | head -20

Phase 2: Analysis

#!/bin/bash

REPO="${1:-${GITHUB_ORG}/${GITHUB_REPO}}"

echo "=== CODEOWNERS Content ==="
CODEOWNERS=$(gh_api "repos/${REPO}/contents/.github/CODEOWNERS" 2>/dev/null || \
    gh_api "repos/${REPO}/contents/CODEOWNERS" 2>/dev/null)
echo "$CODEOWNERS" | jq -r '.content' | base64 -d 2>/dev/null | grep -v '^#' | grep -v '^$' | head -30

echo ""
echo "=== Ownership Summary ==="
echo "$CODEOWNERS" | jq -r '.content' | base64 -d 2>/dev/null | grep -v '^#' | grep -v '^$' | \
    awk '{for(i=2;i<=NF;i++) owners[$i]++} END {for(o in owners) print o"\t"owners[o]" patterns"}' | \
    sort -t$'\t' -k2 -rn | column -t | head -20

echo ""
echo "=== Wildcard Patterns ==="
echo "$CODEOWNERS" | jq -r '.content' | base64 -d 2>/dev/null | grep -v '^#' | grep '\*' | head -15

echo ""
echo "=== Repos Without CODEOWNERS ==="
gh_api "orgs/${GITHUB_ORG}/repos?per_page=20&sort=updated" | jq -r '.[].full_name' | while read repo; do
    HAS=false
    for path in ".github/CODEOWNERS" "CODEOWNERS" "docs/CODEOWNERS"; do
        if gh_api "repos/${repo}/contents/${path}" 2>/dev/null | jq -e '.name' >/dev/null 2>&1; then
            HAS=true; break
        fi
    done
    [ "$HAS" = "false" ] && echo -e "${repo}\tNO CODEOWNERS"
done | column -t | head -15

Output Rules

• TOKEN EFFICIENCY: Target <=50 lines per output
• Summarize ownership patterns rather than dumping full files
• Focus on gaps and issues rather than complete listings

Output Format

Present results as a structured report:

Managing Codeowners Report
══════════════════════════
Resources discovered: [count]

Resource       Status    Key Metric    Issues
──────────────────────────────────────────────
[name]         [ok/warn] [value]       [findings]

Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]

Target ≤50 lines of output. Use tables for multi-resource comparisons.

Anti-Hallucination Rules

1. NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
2. NEVER fabricate metric names or dimensions — verify against the service documentation or --help output.
3. NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
4. ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
5. ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.

Counter-Rationalizations

Shortcut	Counter	Why
"I'll skip discovery and check known resources"	Always run Phase 1 discovery first	Resource names change, new resources appear — assumed names cause errors
"The user only asked for a quick check"	Follow the full discovery → analysis flow	Quick checks miss critical issues; structured analysis catches silent failures
"Default configuration is probably fine"	Audit configuration explicitly	Defaults often leave logging, security, and optimization features disabled
"Metrics aren't needed for this"	Always check relevant metrics when available	API/CLI responses show current state; metrics reveal trends and intermittent issues
"I don't have access to that"	Try the command and report the actual error	Assumed permission failures prevent useful investigation; actual errors are informative

Common Pitfalls

• File location: CODEOWNERS must be in .github/, root, or docs/ -- other locations are ignored
• Pattern order: Last matching pattern wins -- order matters for overlapping rules
• Team existence: References to deleted or renamed teams silently fail -- no review required
• Syntax errors: Invalid lines are silently ignored -- validate syntax
• Glob patterns: CODEOWNERS uses gitignore-style patterns, not full regex
• Required reviews: CODEOWNERS only enforces reviews if branch protection requires code owner approval
• Performance: Repositories with very large CODEOWNERS files may have slow PR review assignment