setup

An interactive setup command for configuring an Elixir development environment with ElixirLS and related tools. ElixirLS is a language server that helps editors and coding agents understand Elixir code.

In plain words
What is it for?
It helps prepare ElixirLS, Hex, Rebar, Credo, and LSP support for Claude Code. It is for developers starting Elixir development or setting up a new machine.
Why use it?
It removes the need to install and check each required tool manually. It also verifies that the setup can format an Elixir file.

Command

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 commands/zircote/elixir-lsp/setup
Clone the repo
git clone --depth 1 https://github.com/zircote/elixir-lsp
Per session 9 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 292 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 $0.00009 $0.00292
Opus 5 $0.00005 $0.00146
Sonnet 5 $0.00002 $0.00058
Haiku 4.5 $0.00001 $0.00029

Measured yesterday against content hash 36c891cdd830, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

setup 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 yesterday.

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.

commands/setup.md · 69 lines

What it actually says

Elixir LSP Setup

This command will configure your Elixir development environment with ElixirLS and essential tools.

Prerequisites Check

First, verify Elixir is installed:

elixir --version
mix --version

Installation Steps

1. Install ElixirLS

Download from GitHub releases: https://github.com/elixir-lsp/elixir-ls/releases

Or build from source:

git clone https://github.com/elixir-lsp/elixir-ls.git
cd elixir-ls
mix deps.get && mix compile
mix elixir_ls.release -o release

2. Install Development Tools

# Update hex and rebar
mix local.hex --force
mix local.rebar --force

# Install Credo for linting
mix archive.install hex credo --force

3. Enable LSP in Claude Code

export ENABLE_LSP_TOOL=1

Verification

Test the integration:

# Create a test file
cat > test_lsp.ex << 'EOF'
defmodule Greeter do
  def greet(name), do: "Hello, #{name}!"
end
EOF

# Format
mix format test_lsp.ex

# Clean up
rm test_lsp.ex
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. yesterday First seen · 69 lines · 9 tokens per session scan A 36c891cdd830

Subscribe to this mod's changes

setup is a command published in the GitHub repository zircote/elixir-lsp (1 stars, last pushed 22d ago), licensed MIT. It adds 9 tokens to every session and 292 once invoked, about $0.0000 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 2026-08-31.