elixir-expert

elixir-expert is a skill for Claude Code, Codex from pass-agent/loomkin. It costs 60 tokens per session (697 once invoked), scanned A, original, MIT.

A guide for building Elixir software, including Phoenix web applications and OTP-based systems. OTP is Elixir’s set of tools for concurrent, fault-tolerant programs; BEAM is the virtual machine that runs them.

In plain words
What is it for?
Use it when creating Elixir or Phoenix applications, LiveView interfaces, GenServers, supervisors, background work, database access with Ecto, or distributed BEAM systems.
Why use it?
It helps choose suitable patterns for handling many tasks at once, real-time updates, failures, and distributed systems.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/pass-agent/loomkin/elixir-expert
Any agent
npx skills add pass-agent/loomkin --skill elixir-expert
Clone the repo
git clone --depth 1 https://github.com/pass-agent/loomkin

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for elixir-expert

README.md
[![agentmods](https://agentmods.dev/badge/skills/pass-agent/loomkin/elixir-expert.svg)](https://agentmods.dev/skills/pass-agent/loomkin/elixir-expert)
Your own site
<a href="https://agentmods.dev/skills/pass-agent/loomkin/elixir-expert"><img src="https://agentmods.dev/badge/skills/pass-agent/loomkin/elixir-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 697 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00060 $0.00697
Opus 5 $0.00030 $0.00349
Sonnet 5 $0.00012 $0.00139
Haiku 4.5 $0.00006 $0.00070

Measured 3d ago against content hash 2f2db27a51f3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

elixir-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/elixir-expert/SKILL.md · 94 lines

How it starts

The opening of the file, as written. The whole thing — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Elixir Expert

Purpose

Provides expertise in Elixir development, Phoenix Framework, and OTP patterns. Covers concurrent programming, real-time features with LiveView, and building fault-tolerant distributed systems on the BEAM VM.

When to Use

  • Building Elixir applications
  • Developing Phoenix web applications
  • Implementing real-time features with LiveView
  • Using OTP patterns (GenServer, Supervisor)
  • Building distributed systems on BEAM
  • Designing fault-tolerant architectures
  • Working with Ecto for database access

Quick Start

Invoke this skill when:

  • Building Elixir applications
  • Developing Phoenix web applications
  • Implementing real-time features with LiveView
  • Using OTP patterns
  • Designing fault-tolerant systems

Do NOT invoke when:

  • Building Ruby on Rails apps (use rails-expert)
  • Building Node.js backends (use javascript-pro)
  • Building Python backends (use python-pro)
  • Infrastructure automation (use terraform-engineer)

Decision Framework

Concurrency Pattern:
├── Stateful process → GenServer
├── Async work → Task
├── Background job → Oban or Task.Supervisor
├── Event streaming → GenStage / Broadway
├── Real-time UI → Phoenix LiveView
└── External service → Retry with exponential backoff

Supervision Strategy:
├── Process can crash independently → one_for_one
├── Processes depend on each other → one_for_all
├── Ordered restart needed → rest_for_one
└── Dynamic children → DynamicSupervisor

Core Workflows

1. Phoenix Application Setup

  1. Generate Phoenix project
  2. Configure database with Ecto
  3. Define schemas and migrations
  4. Create contexts for business logic
  5. Build controllers or LiveViews
  6. Add authentication
  7. Deploy with releases

2. OTP Application Design

  1. Identify stateful components
  2. Design supervision tree
  3. Implement GenServers for state
  4. Add proper error handling
  5. Implement graceful shutdown
  6. Test supervision strategies

3. Real-Time with LiveView

  1. Generate LiveView module
  2. Define assigns and state
  3. Implement handle_event callbacks
  4. Use pubsub for broadcasts
  5. Optimize with temporary_assigns
  6. Add JS hooks if needed

Read the full file on GitHub · 94 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 94 lines · 60 tokens per session scan A 2f2db27a51f3

Subscribe to this mod's changes

elixir-expert is a skill published in the GitHub repository pass-agent/loomkin (179 stars, last pushed 3mo ago), licensed MIT. It adds 60 tokens to every session and 697 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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