Claude Code plugin marketplace for Elixir development
# Add to your Claude Code skills
git clone https://github.com/georgeguimaraes/claude-code-elixirClaude Code plugins for Elixir development.
claude plugin marketplace add georgeguimaraes/claude-code-elixir
Install all plugins:
claude plugin install elixir-lsp@claude-code-elixir && \
claude plugin install mix-format@claude-code-elixir && \
claude plugin install mix-compile@claude-code-elixir && \
claude plugin install mix-credo@claude-code-elixir && \
claude plugin install elixir@claude-code-elixir
Install the expert binary and make sure it's on your PATH. See installation instructions.
Note:
mix-format,mix-compile, andmix-credorequire bash (Git Bash or WSL on Windows).
| Plugin | Type | Description |
|--------|------|-------------|
| elixir-lsp | LSP | Language Server with completions, go-to-definition, diagnostics |
| mix-format | Hook | Auto-format .ex/.exs files on save |
| mix-compile | Hook | Compile with --warnings-as-errors on save |
| mix-credo | Hook | Run Credo code quality checks on save |
| elixir | Skills | BEAM architecture, Phoenix, Ecto, OTP patterns |
Elixir Language Server integration powered by Expert.
| Feature | Description | |---------|-------------| | Navigation | Go to definition, find references | | Completions | With signature help and docs | | Diagnostics | Compiler warnings and errors | | File types | , , , |
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.ex.exs.heex.leexAuto-runs mix format after editing .ex and .exs files.
Auto-runs mix compile --warnings-as-errors after editing .ex files.
.ex files (not .exs scripts/tests)mix.exs by walking up directoriesAuto-runs mix credo after editing .ex and .exs files to check code quality.
.ex and .exs filesParadigm-shifting skills for Elixir, Phoenix, and OTP development. Includes a SessionStart hook that auto-suggests skills when working on Elixir code.
Included skills:
| Skill | Use When |
|-------|----------|
| elixir-thinking | Designing modules, processes, data structures |
| phoenix-thinking | Working with Phoenix, LiveView, PubSub |
| ecto-thinking | Working with Ecto, contexts, schemas |
| otp-thinking | Implementing GenServers, supervisors, Tasks |
Mental models for writing Elixir — how it differs from OOP.
| Concept | Insight | |---------|---------| | Iron Law | NO PROCESS WITHOUT A RUNTIME REASON | | Three dimensions | Behavior, state, mutability are decoupled | | Processes | For runtime (state/concurrency/faults), not code organization | | "Let it crash" | Means "let it heal" — supervisors restart | | Polymorphism | Behaviors → Protocols → Message passing (least to most dynamic) |
Architectural patterns for Phoenix and LiveView.
| Concept | Insight |
|---------|---------|
| Iron Law | NO DATABASE QUERIES IN MOUNT |
| Scopes (1.8+) | Security-first authorization threading |
| mount vs handle_params | mount = setup, handle_params = data |
| PubSub | Scoped topics, broadcast_from to avoid self-broadcast |
| Channel fastlane | Socket state can be stale — re-fetch or include in broadcast |
Architectural patterns for Ecto and contexts.
| Concept | Insight |
|---------|---------|
| Contexts | Bounded domains with their own "dialect" |
| Cross-context refs | Use IDs, not belongs_to associations |
| Schemas | Multiple changesets per schema, embedded_schema for forms |
| Preloads | Separate vs join — pick based on data shape |
| pool_count vs pool_size | pool_count = DBConnection pools, pool_size = connections per pool |
OTP design patterns and when to use each abstraction.
| Concept | Insight |
|---------|---------|
| Iron Law | GENSERVER IS A BOTTLENECK BY DESIGN |
| ETS | Bypasses bottleneck — concurrent reads with :read_concurrency |
| Task.Supervisor | THE pattern for async work (not raw Task.async) |
| Registry + DynamicSupervisor | Named dynamic processes without atom leaks |
| Broadway vs Oban | External queues vs background jobs — different problems |
elixir-lsp: client/registerCapability workaround. Claude Code's LSP client doesn't respond to client/registerCapability requests that Expert sends during initialization (anthropics/claude-code#32595). The plugin includes a Python wrapper (expert-wrapper) that intercepts these requests and auto-responds so Expert can initialize properly. The wrapper will be removed once the upstream fix lands. Requires Python 3 on PATH.
expert not found: Ensure the expert binary is on your PATH. See installation instructions.
Copyright (c) 2025 George Guimarães
Licensed under the Apache License, Version 2.0. See LICENSE for details.