ln-625-dependencies-auditor skill

---
name: ln-625-dependencies-auditor
description: "Dependencies audit worker (L3). Checks outdated packages, unused deps, reinvented wheels, vulnerability scan (CVE/CVSS). Supports mode: full | vulnerabilities_only."
allowed-tools: Read, Grep, Glob, Bash
---

> **Paths:** File paths (`shared/`, `references/`, `../ln-*`) are relative to skills repo root. If not found at CWD, locate this SKILL.md directory and go up one level for repo root.

# Dependencies & Reuse Auditor (L3 Worker)

Specialized worker auditing dependency management, code reuse, and security vulnerabilities.

## Purpose & Scope

- **Worker in ln-620 coordinator pipeline** (full audit mode)
- **Worker in ln-760 security-setup pipeline** (vulnerabilities_only mode)
- Audit **dependencies and reuse** (Categories 7+8: Medium Priority)
- Check outdated packages, unused deps, wheel reinvention, **CVE vulnerabilities**
- Calculate compliance score (X/10)

## Parameters

| Param | Values | Default | Description |
|-------|--------|---------|-------------|
| mode | `full` / `vulnerabilities_only` | `full` | `full` = all 5 checks, `vulnerabilities_only` = only CVE scan |

## Inputs (from Coordinator)

Receives `contextStore` with tech stack, package manifest paths, codebase root, output_dir.

**From ln-620 (codebase-auditor):** mode=full (default)
**From ln-760 (security-setup):** mode=vulnerabilities_only

## Workflow

1) Parse context + mode parameter + output_dir
2) Run dependency checks (based on mode)
3) Collect findings
4) Calculate score
5) **Write Report:** Build full markdown report in memory per `shared/templates/audit_worker_report_template.md`, write to `{output_dir}/625-dependencies.md` in single Write call
6) **Return Summary:** Return minimal summary to coordinator

---

## Audit Rules (5 Checks)

### 1. Outdated Packages
**Mode:** full only

**Detection:**
- Run `npm outdated --json` (Node.js)
- Run `pip list --outdated --format=json` (Python)
- Run `cargo outdated --format=json` (Rust)

**Severity:**
- **HIGH:** Major version behind (security risk)
- **MEDIUM:** Minor version behind
- **LOW:** Patch version behind

**Recommendation:** Update to latest version, test for breaking changes

**Effort:** S-M (update version, run tests)

### 2. Unused Dependencies
**Mode:** full only

**Detection:**
- Parse package.json/requirements.txt
- Grep codebase for `import`/`require` statements
- Find dependencies never imported

**Severity:**
- **MEDIUM:** Unused production dependency (bloats bundle)
- **LOW:** Unused dev dependency

**Recommendation:** Remove from package manifest

**Effort:** S (delete line, test)

### 3. Available Features Not Used
**Mode:** full only

**Detection:**
- Check for axios when native fetch available (Node 18+)
- Check for lodash when Array methods sufficient
- Check for moment when Date.toLocaleString sufficient

**Severity:**
- **MEDIUM:** Unnecessary dependency (increases bundle size)

**Recommendation:** Use native alternative

**Effort:** M (refactor code to use native API)

### 4. Custom Implementations
**Mode:** full only

**Detection:**
- Grep for custom sorting algorithms
- Check for hand-rolled validation (vs validator.js)
- Find custom date parsing (vs date-fns/dayjs)

**Severity:**
- **HIGH:** Custom crypto (security risk)
- **MEDIUM:** Custom utilities with well-tested alternatives

**Recommendation:** Replace with established library

**Effort:** M (integrate library, replace calls)

### 5. Vulnerability Scan (CVE/CVSS)
**Mode:** full AND vulnerabilities_only

**Detection:**
- Detect ecosystems: npm, NuGet, pip, Go, Bundler, Cargo, Composer
- Run audit commands per `references/vulnerability_commands.md`
- Parse results with CVSS mapping per `shared/references/cvss_severity_mapping.md`

**Severity:**
- **CRITICAL:** CVSS 9.0-10.0 (immediate fix required)
- **HIGH:** CVSS 7.0-8.9 (fix within 48h)
- **MEDIUM:** CVSS 4.0-6.9 (fix within 1 week)
- **LOW:** CVSS 0.1-3.9 (fix when convenient)

**Fix Classification:**
- Patch update (x.x.Y) → safe auto-fix
- Minor update (x.Y.0) → usually safe
- Major update (Y.0.0) → manual review required
- No fix available → document and monitor

**Recommendation:** Update to fixed version, verify lock file integrity

**Effort:** S-L (depends on breaking changes)

---

## Scoring Algorithm

**MANDATORY READ:** Load `shared/references/audit_scoring.md` for unified scoring formula.

**Note:** When mode=vulnerabilities_only, score based only on vulnerability findings.

## Output Format

**MANDATORY READ:** Load `shared/templates/audit_worker_report_template.md` for file format.

Write report to `{output_dir}/625-dependencies.md` with `category: "Dependencies & Reuse"` and checks: outdated_packages, unused_deps, available_natives, custom_implementations, vulnerability_scan.

Return summary to coordinator:
```
Report written: docs/project/.audit/625-dependencies.md
Score: X.X/10 | Issues: N (C:N H:N M:N L:N)
```

## Reference Files

| File | Purpose |
|------|---------|
| `shared/templates/audit_worker_report_template.md` | Worker report file format |
| `references/vulnerability_commands.md` | Ecosystem-specific audit commands |
| `references/ci_integration_guide.md` | CI/CD integration guidance |
| `shared/references/cvss_severity_mapping.md` | CVSS to severity level mapping |
| `shared/references/audit_scoring.md` | Audit scoring formula |
| `shared/references/audit_output_schema.md` | Audit output schema |

## Critical Rules

- **Do not auto-fix:** Report only, never modify package manifests or lock files
- **Mode-aware execution:** In `vulnerabilities_only` mode, skip checks 1-4 entirely
- **Effort realism:** S = <1h, M = 1-4h, L = >4h
- **CVSS-based severity:** Map vulnerability severity strictly via `shared/references/cvss_severity_mapping.md`
- **Exclusions:** Skip devDependencies for vulnerability severity escalation, skip vendored/bundled deps

## Definition of Done

- contextStore parsed (including mode parameter and output_dir)
- All applicable checks completed (5 for full, 1 for vulnerabilities_only)
- Findings collected with severity, location, effort, fix_type, recommendation
- Score calculated per `shared/references/audit_scoring.md`
- Report written to `{output_dir}/625-dependencies.md` (atomic single Write call)
- Summary returned to coordinator

---
**Version:** 4.0.0
**Last Updated:** 2026-02-05