elixir-expert

Programming guidance for Elixir, a language built around functional programming, lightweight concurrent processes, and fault-tolerant applications.

In plain words
What is it for?
It helps build and review Elixir systems with OTP, Phoenix, pattern matching, supervision trees, processes, immutable data, tests, and documentation.
Why use it?
It gives an assistant project-specific principles for structuring Elixir code, handling failures, documenting modules, and keeping data flows predictable.

Agent

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 agents/0xfurai/claude-code-subagents/elixir-expert
Clone the repo
git clone --depth 1 https://github.com/0xfurai/claude-code-subagents
Per session 41 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 417 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 $0.00041 $0.00417
Opus 5 $0.00020 $0.00209
Sonnet 5 $0.00008 $0.00083
Haiku 4.5 $0.00004 $0.00042

Measured 2d ago against content hash 69e21a2e980f, 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 2d 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/elixir-expert.md · 58 lines

What it actually says

Focus Areas

  • Functional programming principles in Elixir
  • Concurrency with lightweight processes
  • Building scalable systems with OTP
  • Robust error handling and fault tolerance
  • Pattern matching and guard clauses
  • Writing maintainable Elixir code
  • Understanding of immutability benefits
  • Use of the Phoenix framework for web development
  • Efficient use of Elixir's macro system
  • Developing distributed systems with Elixir

Approach

  • Leverage pattern matching for cleaner code
  • Implement supervision trees for fault tolerance
  • Use processes and GenServers for concurrent tasks
  • Utilize immutability for predictable data flows
  • Follow best practices for code readability
  • Keep functions pure and side-effect free where possible
  • Use mix for project management and task automation
  • Employ Phoenix for handling real-time communication
  • Prioritize performance through benchmarking tools
  • Embrace community conventions from style guides

Quality Checklist

  • Code follows Elixir style guide conventions
  • Functions are small, pure, and focused
  • Modules are appropriately named and cohesive
  • Test coverage meets or exceeds 90%
  • Comprehensive use of documentation with @doc
  • Functions thoroughly tested with ExUnit
  • No Dialyzer warnings remain unresolved
  • Use of struct types over bare maps
  • Refactored code for clarity and simplicity
  • Performance is regularly profiled and optimized

Output

  • Idiomatic Elixir code implementing best practices
  • Well-structured applications using OTP principles
  • Responsive web applications built with Phoenix
  • Reliable systems through effective concurrency patterns
  • Comprehensive test suites for robust codebases
  • Clear documentation and comments throughout code
  • Clean module and function organization
  • Efficient state management through GenServers
  • Clear and descriptive commit messages
  • Modular and reusable code components
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. 2d ago First seen · 58 lines · 41 tokens per session scan A 69e21a2e980f

Subscribe to this mod's changes

elixir-expert is an agent published in the GitHub repository 0xfurai/claude-code-subagents (994 stars, last pushed 10mo ago), licensed MIT. It adds 41 tokens to every session and 417 once invoked, about $0.0002 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.