Installing Chasm

Requires Node.js 18+, npm, git, and Python 3.

Quick install (one-liner):

curl -sSL https://chasm.run/web-install.sh | bash

Or clone manually:

git clone https://github.com/atisharma/chasm.git
cd chasm
./install.sh --local

If pi is not on your PATH, the installer will install it via npm.

Configure a model

When starting play, configure a model provider with /login.

Chasm requires a model with tool-use support (function calling). Good choices as of 2026: Kimi K2.5, Mistral Medium 3.5, Sonnet 4.5 and so on. You can configure local models via vLLM too — edit ~/.local/share/chasm/template/models.json. Qwen 3.6 and Gemma 4 both work well.

During play, switch models with Ctrl+L.

Create and play a world

chasm new sunken-quarter
chasm play sunken-quarter

First launch triggers a short Q&A — title, setting, genre, tone, a unique rule, and starting place. The narrator then drops you into the world.

Resume later: chasm play sunken-quarter.

Manage worlds

chasm list
chasm delete sunken-quarter