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Command Line Interface (CLI)

PydanticAI comes with a simple reference CLI application which you can use to interact with various LLMs directly from the command line. It provides a convenient way to chat with language models and quickly get answers right in the terminal.

We originally developed this CLI for our own use, but found ourselves using it so frequently that we decided to share it as part of the PydanticAI package.

We plan to continue adding new features, such as interaction with MCP servers, access to tools, and more.

Installation

To use the CLI, you need to either install pydantic-ai, or install pydantic-ai-slim with the cli optional group:

pip install "pydantic-ai[cli]"

uv add "pydantic-ai[cli]"

To enable command-line argument autocompletion, run:

register-python-argcomplete pai >> ~/.bashrc  # for bash
register-python-argcomplete pai >> ~/.zshrc   # for zsh

Usage

You'll need to set an environment variable depending on the provider you intend to use.

If using OpenAI, set the OPENAI_API_KEY environment variable:

export OPENAI_API_KEY='your-api-key-here'

Then simply run:

$ pai

This will start an interactive session where you can chat with the AI model. Special commands available in interactive mode:

  • /exit: Exit the session
  • /markdown: Show the last response in markdown format
  • /multiline: Toggle multiline input mode (use Ctrl+D to submit)

Choose a model

You can specify which model to use with the --model flag:

$ pai --model=openai:gpt-4 "What's the capital of France?"