Ln 644 Dependency Topology Auditor

> **Paths:** File paths (`references/`, `../ln-*`) are relative to this skill directory.

**Type:** L3 Worker
**Category:** 6XX Audit

# Dependency Topology Auditor

L3 Worker that builds and analyzes the module dependency graph to enforce architectural boundaries.

## Purpose & Scope

- Build module dependency topology from import statements (Python, TS/JS, C#, Java)
- Detect circular dependencies: pairwise (HIGH) + transitive via DFS (CRITICAL)
- Validate boundary rules: forbidden, allowed, required (per dependency-cruiser pattern)
- Calculate Robert C. Martin metrics (Ca, Ce, Instability) + Lakos aggregate (CCD, NCCD)
- Validate Stable Dependencies Principle (SDP)
- Support baseline/freeze for incremental legacy adoption (per ArchUnit FreezingArchRule)
- **Adaptive:** 3-tier architecture detection -- custom rules > docs > auto-detect
- Emit `BREAK_CYCLE`, `ENFORCE_RULE`, or `REDUCE_COUPLING`

**Out of Scope:**
- I/O isolation violations
- API contract violations
- Code duplication

## Input

```
- architecture_path: string    # Path to docs/architecture.md
- codebase_root: string        # Root directory to scan
- output_dir: string           # e.g., ".hex-skills/runtime-artifacts/runs/{run_id}/audit-report"

# Domain-aware (optional)
- domain_mode: "global" | "domain-aware"   # Default: "global"
- current_domain: string                   # e.g., "users", "billing" (only if domain-aware)
- scan_path: string                        # e.g., "src/users/" (only if domain-aware)

# Baseline (optional)
- update_baseline: boolean                 # If true, save current state as baseline
```

**When domain_mode="domain-aware":** Use `scan_path` instead of `codebase_root` for all Grep/Glob operations. Tag all findings with `domain` field.

## Workflow

Detection policy: use two-layer detection (candidate scan, then context verification); load `references/two_layer_detection.md` only when the verification method is ambiguous.
Tool policy: follow host AGENTS.md MCP preferences; load `references/mcp_tool_preferences.md` and `references/mcp_integration_patterns.md` only when host policy is absent or MCP behavior is unclear.

Use `hex-graph` first when dependency topology, cycles, or architecture metrics materially improve the audit. Use `hex-line` first for local code and config reads when available. If MCP is unavailable, unsupported, or not indexed, continue with built-in `Read/Grep/Glob/Bash` and state the fallback in the report.