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Analyze Phoenix context boundaries and module coupling via mix xref. Use when checking cross-context calls, validating dependencies, before splitting modules, or reviewing architecture.
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
CONTRIBUTOR TOOL - Cut a plugin release: bump plugin.json version, finalize CHANGELOG, update README if needed, gate on make ci, commit, tag vX.Y.Z, and create the GitHub release. Use when shipping a new plugin version. NOT distributed.
OTP/BEAM patterns and Elixir idioms — GenServer, Supervisor, Task, Registry, pattern matching, with chains, pipes. Use when designing processes or debugging BEAM issues.
Verify Elixir/Phoenix changes — compile, format, and test in one loop. Use after implementation, before PRs, or after fixing bugs.
Project health audit and health check — architecture, performance, tests, dependencies, code quality. Use when assessing overall project health, before releases, or after refactors.
Recommend safe Bash permissions for Elixir mix commands in settings.json. Use when permission prompts slow workflow, "fix permissions", "reduce prompts", "auto-allow mix".
Analyze Elixir/Phoenix performance — N+1 queries, assign bloat, ecto optimization, genserver bottlenecks. Use when slowness, timeouts, or high memory reported.
| name | phx:boundaries |
| description | Analyze Phoenix context boundaries and module coupling via mix xref. Use when checking cross-context calls, validating dependencies, before splitting modules, or reviewing architecture. |
| effort | medium |
| argument-hint | ["--assess|--fix"] |
| allowed-tools | Read, Grep, Glob, Bash |
Analyze module dependencies to ensure clean context separation and proper architectural boundaries.
/phx:boundaries # Check for violations
/phx:boundaries --assess # Score context health (0-100)
/phx:boundaries --fix # Suggest fixes for violations
--assess Mode: Context Health ScoreEvaluate overall boundary health with a quantified score.
| Metric | Healthy Range | Red Flag | Weight |
|---|---|---|---|
| Modules per context | 3-15 | >20 or <2 | 20% |
| Public API surface | 5-30 funcs | >40 funcs | 15% |
| Fan-out (contexts called) | 1-4 | >6 | 20% |
| Fan-in (called by contexts) | 1-6 | >10 | 15% |
| Circular dependencies | 0 | >0 | 15% |
| Boundary violations | 0 | >0 | 15% |
Use Glob to count .ex files per context directory under lib/my_app/*/.
Use Grep to count public function definitions per context file under lib/my_app/*.ex.
Run mix xref graph --format stats for dependency analysis.
Run mix xref graph --format cycles --label compile for compile-time circular dependencies.
## Context Health Assessment
### Overall Score: 82/100 (Good)
| Context | Modules | API | Fan-Out | Fan-In | Score |
|---------|---------|-----|---------|--------|-------|
| Accounts | 5 | 12 | 2 | 4 | 95 |
| Orders | 18 | 45 | 8 | 3 | 62 |
| Shared | 2 | 8 | 0 | 12 | 78 |
### Issues Found
1. **Orders** - Too large (18 modules, 45 funcs)
- Consider: Extract Fulfillment, Invoicing sub-contexts
2. **Orders** - High fan-out (8 contexts)
- Consider: Review if all dependencies necessary
### Recommendations
- Split Orders into Orders + Fulfillment
- Review Accounts ← Billing dependency
mix xref first — Refactoring without dependency data creates new violations; always map the dependency graph before moving modules| Layer | Can Call | Cannot Call |
|---|---|---|
| Controllers | Contexts, Plug, Conn | Repo, Schemas directly |
| LiveViews | Contexts, Components, PubSub | Repo, Schemas directly |
| Contexts | Own schemas, Repo, other contexts | Web layer modules |
| Schemas | Ecto types, validations | Contexts, Repo |
Run mix xref graph --label compile-connected.
Run mix xref graph --sink MyApp.Accounts --label compile.
Run mix xref callers MyApp.Accounts.get_user!/1.
Run mix xref graph --format cycles --label compile.
| Issue | Detection Command | Fix |
|---|---|---|
| Repo in web layer | grep -r "Repo\." lib/my_app_web/ | Move to context |
| Schema with queries | grep -r "import Ecto.Query" lib/my_app/**/schemas/ | Move queries to context |
| Cross-context schema import | grep -r "alias MyApp.Other.Schema" lib/my_app/ctx/ | Call context API |
| Business logic in LiveView | grep -r "Repo\.|Ecto\.Multi" lib/my_app_web/live/ | Extract to context |
mix xref graph --label compile-connected for overviewAlways end with actionable follow-up — findings without a plan get lost:
- `/phx:plan` — Create a plan to fix violations (recommended for 3+ issues)
- `/phx:quick` — Fix a single boundary violation directly
- `/phx:review` — Review specific modules for deeper issues
For detailed patterns, see:
${CLAUDE_SKILL_DIR}/references/context-design.md - Context design principles${CLAUDE_SKILL_DIR}/references/refactoring-boundaries.md - Fixing boundary violations