BehavTest › Reference

Installation

BehavTest needs Node.js 24 or newer (node --version). It runs on Linux, macOS and Windows.

npx behavtest --version          # run it without installing
npm install --global behavtest   # or install the CLI globally
npm install --save-dev behavtest # or add it to a project (needed only to import tracer / defineSuite)

Your application does not have to be written in JavaScript: BehavTest calls it over HTTP, or calls OpenAI-compatible and Anthropic models directly. Provider keys are read from OPENAI_API_KEY / ANTHROPIC_API_KEY only when a suite uses those providers or the LLM judge.