Welcome to Runa

What's Runa?

Runa is an opiniated Python framework for building agentic AI applications: instead of a wide menu of configuration options, it gives you a small set of primitives, each with exactly one sanctioned shape.

Understanding those primitives is key to understanding Runa. They divide your application into three layers: the Agent layer, the Context layer, and the Infrastructure layer, with testing, evaluation, and tracing built in rather than bolted on.

Agent layer

The Agent layer is where your application decides what to do. An Agent is an LLM equipped with instructions and tools, always defined as a subclass, never instantiated directly:

class SupportAgent(Agent):
    name = "support_agent"
    model = "claude-sonnet-5"
    instruction = ""
    tools = [...]

Tools let an agent take action in the world, always a plain function wrapped in @tool. Guardrails validate what goes in and what comes out, tripping in list order so the first failure stops the rest. Human Approval pauses a run before a sensitive tool call executes, until a person signs off. Subagents let one agent delegate or hand off work to another.

Context layer

The Context layer is what an agent remembers between and within runs. Sessions hold the conversation for a single run. Memory carries facts forward across runs. Knowledge gives an agent access to your domain's documents, retrieved rather than pasted into the prompt.

Infrastructure layer

The Infrastructure layer is responsible for connecting an agent to the outside world and to the model that powers it. MCP Servers expose external tools and resources over the Model Context Protocol. Models are configured per agent, not globally, so different agents can run on different providers. Hooks let you observe or intercept a run at well-defined points without subclassing.

Built in, not bolted on

Every run is traced automatically as a span tree (Tracing), so you can see exactly what an agent did and why. Evaluation (Eval) grades correctness with plain assertions or judged, dataset-driven scoring.

Getting Started

1. Install uv, then Runa:

   uv venv --python 3.14
   source .venv/bin/activate
   uv add runa-ai
   

2. Scaffold a new application:

   runa new myapp
   

   where myapp is the application name.

3. Change directory to myapp, generate an agent, and talk to it:

   cd myapp
   runa generate agent AssistantAgent --model claude-sonnet-5
   runa chat assistant_agent
   

   Run any subcommand with --help for options.

4. Fill in the API key for whichever model you use in .env, and you're running.

5. Follow the guides to keep building your application. You may find the following resources handy:

   • Getting Started with Runa
   • Runa Guides
   • CLI Reference

Read the Zen of Runa

python -c "from runa import this"

Contributing

We encourage you to contribute to Runa! Check out CONTRIBUTING.md for guidelines about how to proceed.

Trying to report a possible security vulnerability in Runa? Please check out SECURITY.md for guidelines about how to proceed.

Everyone interacting in Runa's codebase, issue tracker, and discussions is expected to follow the code of conduct.

License

Runa is released under the MIT License.