cloudthinker-ai Earthly Build System Management Skill
Manage and analyze Earthly builds, targets, artifacts, and remote execution.
MANDATORY: Discovery-First Pattern
Always check current Earthfile configuration and target structure before modifying builds.
Phase 1: Discovery
#!/bin/bash
echo "=== Earthfile ==="
cat Earthfile 2>/dev/null | head -30
echo ""
echo "=== Earthly Version ==="
earthly --version 2>/dev/null
echo ""
echo "=== Available Targets ==="
grep -E '^\w+:' Earthfile 2>/dev/null | sed 's/://' | head -15
echo ""
echo "=== Nested Earthfiles ==="
find . -name "Earthfile" -not -path "*/node_modules/*" 2>/dev/null | head -10
Phase 2: Analysis
#!/bin/bash
echo "=== Target Dependencies ==="
grep -E '^\w+:|BUILD|COPY|FROM' Earthfile 2>/dev/null | head -25
echo ""
echo "=== Artifacts ==="
grep -E 'SAVE ARTIFACT|SAVE IMAGE' Earthfile 2>/dev/null | head -10
echo ""
echo "=== Cache Mounts ==="
grep -E 'CACHE|--mount.*cache' Earthfile 2>/dev/null | head -10
echo ""
echo "=== Satellite Status ==="
earthly sat ls 2>/dev/null | head -5
Output Rules
- TOKEN EFFICIENCY: Target <=50 lines per output
- List targets with their FROM base images
- Summarize artifact outputs concisely
- Report satellite/remote runner status
Common Operations
Build Target
#!/bin/bash
TARGET="${1:?Target name required}"
echo "=== Building +$TARGET ==="
earthly "+$TARGET" 2>&1 | tail -20
Cache Analysis
#!/bin/bash
echo "=== Cache Usage ==="
earthly prune --dry-run 2>/dev/null | head -10
echo ""
echo "=== Image Cache ==="
docker images --filter "label=dev.earthly" --format "table {{.Repository}}\t{{.Size}}\t{{.CreatedAt}}" 2>/dev/null | head -10
Safety Rules
- Never run
earthly prune -awithout confirming rebuild cost - Use secrets via
--secretflag, never hardcode in Earthfiles - Test multi-platform builds locally before pushing to CI
- Review SAVE IMAGE targets to avoid pushing unintended images to registries
Output Format
Present results as a structured report:
Managing Earthly 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 |