cloudthinker-ai Pants Build System Management Skill
Manage and analyze Pants build targets, dependency inference, and execution.
MANDATORY: Discovery-First Pattern
Always check current Pants configuration and target structure before modifying builds.
Phase 1: Discovery
#!/bin/bash
echo "=== Pants Configuration ==="
cat pants.toml 2>/dev/null | head -25
echo ""
echo "=== Pants Version ==="
pants --version 2>/dev/null
echo ""
echo "=== BUILD Files ==="
find . -name "BUILD" -not -path "*/node_modules/*" 2>/dev/null | head -15
echo ""
echo "=== Enabled Backends ==="
grep -A10 '\[GLOBAL\]' pants.toml 2>/dev/null | grep backend | head -10
Phase 2: Analysis
#!/bin/bash
echo "=== All Targets ==="
pants list :: 2>/dev/null | head -20
echo ""
echo "=== Target Types ==="
pants list --output=json :: 2>/dev/null | jq -r '.[].target_type' 2>/dev/null | sort | uniq -c | sort -rn | head -10
echo ""
echo "=== Dependency Graph ==="
pants dependencies --transitive :: 2>/dev/null | wc -l | xargs -I{} echo "Total dependency edges: {}"
Output Rules
- TOKEN EFFICIENCY: Target <=50 lines per output
- Summarize targets by type
- Report dependency graph density concisely
- List backends and plugins enabled
Common Operations
Target Dependencies
#!/bin/bash
TARGET="${1:?Target address required}"
echo "=== Dependencies for $TARGET ==="
pants dependencies "$TARGET" 2>/dev/null | head -15
echo ""
echo "=== Dependees ==="
pants dependees "$TARGET" 2>/dev/null | head -10
Build and Test
#!/bin/bash
echo "=== Changed Targets ==="
pants --changed-since=main list 2>/dev/null | head -10
echo ""
echo "=== Test Changed ==="
pants --changed-since=main --changed-dependees=transitive test 2>&1 | tail -15
Safety Rules
- Use
--changed-sinceto limit builds to affected targets in CI - Never disable dependency inference without understanding manual dependency cost
- Test pants.toml changes locally before committing
- Review lockfile updates generated by Pants resolve commands
Output Format
Present results as a structured report:
Managing Pants Build 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
- NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
- NEVER fabricate metric names or dimensions — verify against the service documentation or
--helpoutput. - NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
- ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
- 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 |