# Managing Bazel

> Analyze and manage Bazel workspaces, including BUILD file inspection, target querying, dependency graphs, remote execution, caching configuration, and build performance profiling.

- Skill: `cloudthinker-ai/managing-bazel` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cloudthinker-ai/managing-bazel`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cloudthinker-ai/managing-bazel/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector CAUTION)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools, DevOps & Infra, Dev Tooling
- Tags: Bazel, Bazel Query, Bazelrc, Build Performance, Build System, Dependency Graph, Workspace
- Author: cloudthinker-ai (https://skillmd.com/u/cloudthinker-ai)
- Updated: 2026-08-22
- Page: https://skillmd.com/skills/cloudthinker-ai/managing-bazel

---


# Bazel Build System Management Skill

Manage and analyze Bazel workspaces, build targets, dependencies, and caching.

## MANDATORY: Discovery-First Pattern

**Always check current Bazel workspace and build configuration before modifying targets.**

### Phase 1: Discovery

```bash
#!/bin/bash

echo "=== Workspace Configuration ==="
cat WORKSPACE 2>/dev/null | head -20 || cat WORKSPACE.bazel 2>/dev/null | head -20
cat MODULE.bazel 2>/dev/null | head -20

echo ""
echo "=== .bazelrc Configuration ==="
cat .bazelrc 2>/dev/null | head -15

echo ""
echo "=== Bazel Version ==="
bazel version 2>/dev/null | head -3

echo ""
echo "=== Top-Level Packages ==="
ls */BUILD */BUILD.bazel 2>/dev/null | head -15
```

### Phase 2: Analysis

```bash
#!/bin/bash

echo "=== All Build Targets ==="
bazel query '//...' 2>/dev/null | head -20

echo ""
echo "=== Target Types Summary ==="
bazel query '//...' --output=label_kind 2>/dev/null | awk '{print $1}' | sort | uniq -c | sort -rn | head -10

echo ""
echo "=== External Dependencies ==="
bazel query 'deps(//...)' --output=label 2>/dev/null | grep '@' | sed 's|//.*||' | sort -u | head -10
```

## Output Rules
- **TOKEN EFFICIENCY**: Target <=50 lines per output
- Summarize target counts by rule type
- List external dependencies concisely
- Report build timing from profiles

## Common Operations

### Dependency Graph Query

```bash
#!/bin/bash
TARGET="${1:?Target required (e.g., //src:main)}"
echo "=== Dependencies for $TARGET ==="
bazel query "deps($TARGET)" --output=label 2>/dev/null | head -20
echo ""
echo "=== Reverse Dependencies ==="
bazel query "rdeps(//..., $TARGET)" --output=label 2>/dev/null | head -10
```

### Build Performance Profile

```bash
#!/bin/bash
echo "=== Build Profile ==="
bazel build //... --profile=/tmp/bazel_profile.json 2>/dev/null
cat /tmp/bazel_profile.json 2>/dev/null | jq '{
  total_duration: .traceEvents[-1].ts,
  critical_path: [.traceEvents[] | select(.cat == "critical path") | .name] | .[0:5]
}' 2>/dev/null
```

## Safety Rules

- **Never run `bazel clean --expunge`** without understanding the full rebuild cost
- **Test BUILD file changes** with `bazel build --check_visibility` before committing
- **Remote execution credentials** must be stored in CI secrets, not in .bazelrc
- **Review external dependency updates** carefully -- Bazel pins exact versions for reproducibility

## Output Format

Present results as a structured report:
```
Managing Bazel 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 |