ecto

Elixir Agent Tools

Elixir development guidance for coding agents, with optional Mix checks and Expert language server integration.

Five skills covering language idioms, Phoenix interfaces, Ecto persistence, OTP processes, and Oban jobs. Install them with npx skills, then add optional plugins when you want automatic checks or code navigation.

These skills are small on purpose. Every instruction must change the agent's behavior. Modern coding agents already know the basics. Their context should go toward your code and your problem. We keep only guidance that changes a decision or prevents a demonstrated mistake. If the agent would do the same thing without an instruction, that instruction doesn't belong here.

Installation

Install all five skills with the Skills CLI and choose your agent when prompted. Works with Codex, Claude Code, OpenCode, and other supported agents:

npx skills add georgeguimaraes/elixir-agent-tools --skill '*'

Add -g to make the skills available across projects. Start a new session after installation. Mix checks and code navigation are optional tools you can add later.

Install the same five skills as a plugin. Choose this or npx skills to avoid duplicate skills.

Claude Code

claude plugin marketplace add georgeguimaraes/elixir-agent-tools
claude plugin install elixir-dev@elixir-agent-tools

Codex

codex plugin marketplace add georgeguimaraes/elixir-agent-tools
codex plugin add elixir-dev@elixir-agent-tools

For agents that discover skills under ~/.agents/skills, clone this repository into a persistent location and link each skill:

git clone https://github.com/georgeguimaraes/elixir-agent-tools.git "$HOME/.local/share/elixir-agent-tools"
mkdir -p "$HOME/.agents/skills"
for skill in elixir phoenix ecto otp oban; do
  ln -s "$HOME/.local/share/elixir-agent-tools/plugins/elixir-dev/skills/$skill" "$HOME/.agents/skills/$skill"
done

If a destination already exists, inspect it before replacing it. Start a new session after installation. Updating the clone updates the linked skills.

For other agents with Agent Skills support, install the individual folders from plugins/elixir-dev/skills/ in that agent's skill directory.

Register the local directory instead of the GitHub repository:

codex plugin marketplace add /path/to/elixir-agent-tools
codex plugin add elixir-dev@elixir-agent-tools

Start a new session after installation.

Elixir skills

Each skill has its own discovery description. The agent can load several skills for a task that crosses domains, such as a LiveView form backed by an Ecto changeset. There is no startup hook or mandatory routing skill.

OTP covers work and state managed by running processes. Oban covers jobs that need persistence, retry policies, or scheduling. Phoenix owns interface behavior, while Ecto owns the persistence behind it.

Upgrading to elixir-dev 3.0

Skill names now use their domain directly: elixir, phoenix, ecto, otp, and oban. Remove the -thinking suffix from explicit skill references in your prompts and agent instructions. The using-elixir-skills router and its startup hook have been removed.

The plugin is now named elixir-dev and the marketplace is elixir-agent-tools. If you installed from the old Claude Code marketplace, uninstall the plugins you used from claude-code-elixir, remove that marketplace, and add georgeguimaraes/elixir-agent-tools. Reinstall your chosen plugins with the new marketplace ID using the installation commands above. The old elixir plugin is replaced by elixir-dev.

Update any explicit plugin-qualified skill references to use the new bundle name.

If you installed skills manually, replace your old skill links or copies with the renamed folders under plugins/elixir-dev/skills/.

Sources

The skills draw on Elixir and Erlang documentation, framework guides, and talks about application design:

• José Valim - Gang of None
• Saša Jurić - The Soul of Erlang and Elixir
• Saša Jurić - Clarity
• Designing Elixir Systems with OTP
• Official Elixir Guides
• Phoenix 1.8 Scopes
• Phoenix LiveView Docs
• Stephen Bussey - Real-Time Phoenix
• Phoenix Contexts Guide
• German Velasco - DDD for Phoenix Contexts (ElixirConf 2024)
• Ecto Multi-Tenancy Guide
• Erlang OTP Design Principles
• Elixir GenServer Docs
• Elixir School - OTP Concurrency
• Saša Jurić - Elixir in Action

Optional tools

These tools use native plugins. Add the marketplace for your agent below, then install any tools you want. The skills work without them.

Add the marketplace once:

claude plugin marketplace add georgeguimaraes/elixir-agent-tools

Run only the commands for the tools you want:

claude plugin install mix-format@elixir-agent-tools
claude plugin install mix-compile@elixir-agent-tools
claude plugin install mix-credo@elixir-agent-tools
claude plugin install elixir-lsp@elixir-agent-tools

Add the marketplace once:

codex plugin marketplace add georgeguimaraes/elixir-agent-tools

Run only the commands for the checks you want:

codex plugin add mix-format@elixir-agent-tools
codex plugin add mix-compile@elixir-agent-tools
codex plugin a