Set up in Codex

Codex CLI installs Chucks as a Plugin from the Chucks marketplace. The plugin bundles both pieces — the encounter-builder skill and the Chucks connector, whose tools search the current SRD, look up monsters, build and validate balanced encounters, and roll random encounters. It updates itself when we ship changes, so there's nothing to paste by hand.

These steps require the codex command to be available in your terminal. ChatGPT desktop bundles its own Codex runtime, but OpenAI documents the system CLI separately.

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 check a rule, look up a monster, or build you an encounter. 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. Once everything works, try to check a rule or look up a monster.