Show HN: A11 – typed streams and reusable actions for agentic apps (a11.to)

A11 is a newly launched open-source toolkit designed to transform ordinary asynchronous functions into reusable actions with defined inputs and outputs that can stream effectively. With A11, developers can run the same action locally or distribute it across services or browsers, enabling seamless interactions with AI models. The toolkit supports typed multimodal I/O, remote procedure calls, and orchestration while allowing for the integration of existing workflows and service infrastructures like gRPC and LangGraph without needing a dedicated agent runtime. This innovation is significant for the AI/ML community as it simplifies the development process for agentic applications, making it easier to define and manage complex workflows. A11's ability to handle different media types, declare action lifecycles, and maintain structured error handling enhances the robustness and efficiency of AI applications. Developers can build applications that leverage local resources, interact with AI models, and manage inputs and outputs flexibly, all while preserving the ordinary async code structure—ultimately promoting greater collaboration between human operators and AI agents.