Elixir Review

Elixir / Phoenix Code Review

When to Use

• Reviewing Elixir code (Phoenix, OTP, GenServer, LiveView)
• Evaluating fault tolerance patterns (supervision trees)
• Real-time system review (WebSocket, PubSub)
• Concurrency and scalability assessment

Review Checklist

OTP Patterns

• [ ] Supervision trees properly structured (oneforone, restforone)
• [ ] GenServers have clear purpose (not catch-all)
• [ ] handle_info handles unexpected messages gracefully
• [ ] Timeouts configured for long-running GenServers
• [ ] Process registry used (not PID passing)
• [ ] ETS tables for read-heavy shared state

Phoenix Best Practices

• [ ] Contexts separate business logic from web layer
• [ ] Schemas define changesets with validation
• [ ] Controllers are thin (delegate to context)
• [ ] Plugs for cross-cutting concerns (auth, logging)
• [ ] Ecto queries composed (not raw SQL unless necessary)
• [ ] Background jobs via Oban (not raw Task.async)

Phoenix LiveView

• [ ] handle_event functions are small and focused
• [ ] assign used for all state (no process dictionary)
• [ ] phx-throttle/phx-debounce on frequent events
• [ ] PubSub for real-time updates across users
• [ ] Dead views implement mount/3 with proper assigns
• [ ] live_redirect vs push_patch used correctly

Elixir Best Practices

• [ ] Pattern matching over if/else chains
• [ ] Pipe operator (|>) for data transformations
• [ ] with for multi-step operations with error handling
• [ ] @spec type specs on public functions
• [ ] @doc documentation on public functions
• [ ] Structs for domain entities (not naked maps)
• [ ] Guards for function clause selection
• [ ] Enum and Stream used appropriately (eager vs lazy)

Concurrency

• [ ] Tasks supervised (not fire-and-forget)
• [ ] GenServer state doesn't grow unbounded
• [ ] Message queue monitored (Process.info for mailbox)
• [ ] Backpressure implemented for high-throughput
• [ ] Database connection pool sized correctly

Fault Tolerance

• [ ] "Let it crash" — supervisors restart failed processes
• [ ] Circuit breakers for external service calls
• [ ] Fallback strategies for degraded service
• [ ] Health checks for supervised processes

Output Format

## Elixir Review: [Module]
**Health Score**: X/10
### Issues | Improvements | OTP Notes

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: camilooscargbaptista
• Source: camilooscargbaptista/cto-toolkit
• License: MIT

Install and usage instructions live in the source repository linked above.