Elixir Patterns

When to use this skill

Use this skill when working on Elixir/Phoenix projects and you want maintainable OTP-friendly structure, clear boundaries, and robust error handling.

Core patterns

Mix project hygiene

• mix.exs is the source of truth
• keep deps minimal and explicit
• avoid runtime config surprises (document env vars)

OTP mindset

Prefer:

• supervision trees
• isolated processes for state
• message passing over shared mutable state

Function clarity

• small functions
• pattern matching for branching
• use guard clauses for fast validation

Testing

• ExUnit for unit tests
• keep tests deterministic

Atlarix tool notes

• Explore: inspect mix.exs and lib/ modules; locate supervision tree.
• Build: run mix test.
• Debug: inspect crash logs; confirm supervision restarts aren’t hiding repeated failures.
• Review: check boundaries and that errors include enough context.

Common mistakes to avoid

• Putting too much state in a single process
• Silent failures under supervisors
• Overusing macros instead of plain functions

Mini-checklist

• Supervision is intentional
• Boundaries are clear
• Tests cover critical behavior