Managing Nx Monorepo

---
name: managing-nx-monorepo
description: |
  Use when working with Nx Monorepo — nx monorepo build system management.
  Covers workspace configuration, project graph analysis, affected commands,
  computation caching, task executors, and distributed task execution. Use when
  managing Nx workspaces, analyzing project dependencies, debugging build
  failures, or optimizing CI pipelines.
connection_type: nx
preload: false
---

# Nx Monorepo Build System Management Skill

Manage and analyze Nx monorepo workspaces, project graphs, and build orchestration.

## MANDATORY: Discovery-First Pattern

**Always check current Nx workspace configuration before modifying projects or targets.**

### Phase 1: Discovery

```bash
#!/bin/bash

echo "=== Nx Workspace Configuration ==="
cat nx.json 2>/dev/null | jq '{
  npmScope: .npmScope,
  tasksRunnerOptions: (.tasksRunnerOptions | keys),
  targetDefaults: (.targetDefaults | keys),
  namedInputs: (.namedInputs | keys)
}' 2>/dev/null

echo ""
echo "=== Projects ==="
npx nx show projects 2>/dev/null | head -20

echo ""
echo "=== Nx Version ==="
npx nx --version 2>/dev/null
```

### Phase 2: Analysis

```bash
#!/bin/bash

echo "=== Project Graph Summary ==="
npx nx graph --file=stdout 2>/dev/null | jq '{
  total_projects: (.graph.nodes | length),
  total_dependencies: (.graph.dependencies | map(length) | add),
  projects: [.graph.nodes | to_entries[] | {name: .key, type: .value.type}]
}' 2>/dev/null | head -30

echo ""
echo "=== Affected Projects (since main) ==="
npx nx show projects --affected --base=main 2>/dev/null | head -15

echo ""
echo "=== Cache Status ==="
ls -la .nx/cache/ 2>/dev/null | tail -10
```

## Output Rules
- **TOKEN EFFICIENCY**: Target <=50 lines per output
- Summarize project graphs with counts and types
- List affected projects concisely
- Report cache utilization metrics

## Common Operations

### Run Affected Targets

```bash
#!/bin/bash
TARGET="${1:-build}"
echo "=== Affected $TARGET ==="
npx nx affected -t "$TARGET" --base=main --dry-run 2>/dev/null | head -20
```

### Dependency Analysis

```bash
#!/bin/bash
PROJECT="${1:?Project name required}"
echo "=== Dependencies for $PROJECT ==="
npx nx show project "$PROJECT" --json 2>/dev/null | jq '{
  name: .name,
  targets: (.targets | keys),
  implicitDependencies: .implicitDependencies
}' 2>/dev/null
```

## Safety Rules

- **Run affected commands** before full workspace builds to save CI time
- **Never clear the Nx cache** in production CI without understanding rebuild cost
- **Test executor changes** on individual projects before applying workspace-wide
- **Review project graph** after adding new dependencies to detect circular references

## Output Format

Present results as a structured report:
```
Managing Nx Monorepo 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 |