An Agent Builder agent consists of a UI, which is the agent’s interface, and a blueprint, which is the agent’s logic. The UI and blueprint are connected through the agent’s state and UI triggers.

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Agent components

An agent consists of the following components:

  • UI: the interface that users interact with.
    • UIs are designed using elements like input fields, buttons, and embeds, including support for guided workflows with pagination.
    • They give users a structured, intuitive way to engage with agents, from simple chat interfaces to rich, interactive tools.
    • The UI is optional. If you do not need to receive user input or display output, you can build an agent without a UI by only using the blueprint.
  • Blueprint: a visual map of the agent’s business logic and behavior.
    • Blueprints are created using a library of configurable blocks for tool calling, built-in RAG, text generation, classification, state management, and more.
    • They define how the agent processes input, makes decisions, and takes action—enabling it to reliably orchestrate work across people, data, systems, and even other agents built in Writer.

Additionally, you can add custom Python code to the agent to extend its capabilities with more complex logic.

Check out the demo agent walkthrough to see how these components work together in practice.

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Agent state

Agents use the agent’s state to communicate information across components. The state is a shared memory for each part of the agent: the UI, blueprint, and custom Python code can all read and write data to the state.

Learn more in Agent state.

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Blueprint-only agents

If you don’t need to receive user input or display output, you can build an agent without a UI by only using the blueprint.

To run the blueprint without a UI Trigger, press the Run blueprint button in the top right of the blueprint.