moai-lang-elixir

name	moai-lang-elixir
description	Elixir 1.17+ development specialist covering Phoenix 1.7, LiveView, Ecto, and OTP patterns. Use when developing real-time applications, distributed systems, or Phoenix projects.
license	Apache-2.0
compatibility	Designed for Claude Code
allowed-tools	Read Grep Glob Bash(mix:*) Bash(elixir:*) Bash(iex:*) Bash(erl:*) mcp__context7__resolve-library-id mcp__context7__get-library-docs
user-invocable	false
metadata	{"version":"1.1.0","category":"language","status":"active","updated":"2026-01-11","modularized":"true","tags":"language, elixir, phoenix, liveview, ecto, otp, genserver"}
progressive_disclosure	{"enabled":true,"level1_tokens":100,"level2_tokens":5000}
triggers	{"keywords":["Elixir","Phoenix","LiveView","Ecto","OTP","GenServer",".ex",".exs","mix.exs"],"languages":["elixir"]}

Quick Reference (30 seconds)

Elixir 1.17+ Development Specialist - Phoenix 1.7, LiveView, Ecto, OTP patterns, and functional programming.

Auto-Triggers: .ex, .exs files, mix.exs, config/, Phoenix/LiveView discussions

Core Capabilities:

• Elixir 1.17: Pattern matching, pipes, protocols, behaviours, macros
• Phoenix 1.7: Controllers, LiveView, Channels, PubSub, Verified Routes
• Ecto: Schemas, Changesets, Queries, Migrations, Multi
• OTP: GenServer, Supervisor, Agent, Task, Registry
• ExUnit: Testing with setup, describe, async
• Mix: Build tool, tasks, releases
• Oban: Background job processing

Quick Patterns

Phoenix Controller: Define a module using MyAppWeb with :controller. Create alias for the context module like MyApp.Accounts. Define action functions like show taking conn and params map with destructured id. Fetch data using the context function with bang like get_user! and render the template passing the data as assigns.

For create actions, pattern match on the context result tuple. On ok tuple, use pipe operator to put_flash with success message and redirect using ~p sigil for verified routes. On error tuple with Ecto.Changeset, render the form template passing the changeset.

Ecto Schema with Changeset: Define a module using Ecto.Schema and importing Ecto.Changeset. Define the schema block with field declarations including types like :string and virtual fields. Create a changeset function taking the struct and attrs, using pipe operator to chain cast with the list of fields to cast, validate_required, validate_format with regex, validate_length with min option, and unique_constraint.

GenServer Pattern: Define a module using GenServer. Create start_link taking initial_value and calling GenServer.start_link with MODULE, initial_value, and name option. Define client API functions that call GenServer.call with MODULE and the message atom. Implement init callback returning ok tuple with state. Implement handle_call callbacks for each message, returning reply tuple with response and new state.

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Implementation Guide (5 minutes)

Elixir 1.17 Features

Pattern Matching Advanced: Define function heads with pattern matching on map keys and types. Use guard clauses with when to add constraints like is_binary or byte_size checks. Add a catch-all clause returning error tuple for invalid inputs.

Pipe Operator with Error Handling: Use the with special form for chaining operations that may fail. Pattern match each step with left arrow, and on successful completion of all steps, return the final ok tuple. In the else block, handle error tuples by returning them unchanged.