elixir-phoenix-best-practices

name: elixir-phoenix-best-practices description: "Use when: enforcing Elixir and Phoenix best practices, reviewing contexts/controllers/liveviews, improving changesets/queries, and preparing production-ready Elixir code" license: MIT

Elixir Phoenix Best Practices

Overview

Apply a repeatable workflow to audit and improve Elixir/Phoenix code quality without changing intended behavior.

Use This Skill For

• Elixir/Phoenix code reviews
• Context/controller boundary checks
• Query and changeset quality checks
• Error handling consistency improvements
• Maintainability hardening before merge

Workflow

1. Identify the touched modules and classify each as web layer, domain/context layer, data layer, or integration layer.
2. Verify architectural boundaries:

• Web layer delegates business decisions to context/service modules.
• Context APIs remain stable and explicit.

3. Verify correctness and reliability:

• Fallible flows return tagged tuples.
• Pattern matching and with are used for clarity in multi-step logic.
• External input is validated through changesets or dedicated validators.

4. Verify data access:

• Queries avoid N+1 patterns.
• Transactional writes use Ecto.Multi when atomicity is required.

5. Verify operational quality:

• Logging and telemetry are meaningful and not noisy.
• Tests cover key success and failure paths.

6. Apply minimal, surgical edits aligned with existing project conventions.

Output Format

When using this skill, report findings in this order:

1. Critical correctness/security issues
2. Behavioral regression risks
3. Maintainability and clarity improvements
4. Missing tests or weak coverage areas