Set up in Codex

Codex installs Chucks as a Plugin from the Chucks marketplace. The plugin bundles both pieces — the encounter-builder skill and the Chucks connector, the MCP server whose tools search monsters and assemble balanced encounters — and updates itself when we ship changes, so there's nothing to paste by hand.

1. Add the marketplace

Add the Chucks repository as a plugin marketplace:

codex plugin marketplace add chucks-ai/codex

2. Install the plugin

Then install the Chucks plugin from that marketplace:

codex plugin add chucks@chucks

3. Try it

Start a new session and ask Codex to build you an encounter. The encounter-builder skill kicks in when your prompt looks like an encounter request, and Codex calls the Chucks tools to search monsters and build it. Depending on your approval settings, you may be asked to approve the Chucks tools before they run.

Stuck? See your first encounter for a full worked example, or prompting tips for getting better results.