# Boundaries

Analyze Phoenix context boundaries and module coupling via mix xref.

- Repository: https://github.com/oliver-kriska/claude-elixir-phoenix (572 stars)
- Category: Engineering
- License: MIT
- Last updated: 2026-10-30
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add oliver-kriska/claude-elixir-phoenix --skill boundaries -g -a claude-code -y`
Codex: `npx skills add oliver-kriska/claude-elixir-phoenix --skill boundaries -g -a codex -y`
Cursor: `npx skills add oliver-kriska/claude-elixir-phoenix --skill boundaries -g -a cursor -y`
Gemini CLI: `npx skills add oliver-kriska/claude-elixir-phoenix --skill boundaries -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add oliver-kriska/claude-elixir-phoenix`

## 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.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Phoenix Context Boundary Validation

Analyze module dependencies to ensure clean context separation and proper architectural boundaries.

## Usage

```
/phx:boundaries              # Check for violations
/phx:boundaries --assess     # Score context health (0-100)
/phx:boundaries --fix        # Suggest fixes for violations
```

## `--assess` Mode: Context Health Score

Evaluate overall boundary health with a quantified score.

### Metrics Calculated

| 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% |

### Commands for Assessment

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.

### Output Format

```markdown
## 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
```

## Iron Laws - Never Violate These

The rest: https://github.com/oliver-kriska/claude-elixir-phoenix/blob/HEAD/plugins/elixir-phoenix/skills/boundaries/SKILL.md