Browser-Use

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Architecture Reference ​

Browser-Use is built with a modular architecture designed to bridge language models with browser automation. This document explains the core components of the system and how they work together to enable AI agents to interact with web browsers effectively.

System Overview ​

At a high level, Browser-Use follows this architecture:

+----------------+      +----------------+      +----------------+
|                |      |                |      |                |
|  Language      |<---->|  Browser-Use   |<---->|  Browser       |
|  Model (LLM)   |      |  Core          |      |  (Playwright)  |
|                |      |                |      |                |
+----------------+      +----------------+      +----------------+
                              ^    ^
                              |    |
                              v    v
                        +----------------+
                        |                |
                        |  Memory        |
                        |  (Optional)    |
                        |                |
                        +----------------+

Core Components ​

Agent ​

The Agent class is the primary interface for users. It coordinates all other components and manages the overall process of executing browser automation tasks. Key responsibilities include:

  • Accepting natural language task descriptions
  • Planning and executing multi-step browser actions
  • Managing the execution flow of browser operations
  • Interfacing with the language model for decision-making
  • Handling errors and adapting to changing page conditions
python
agent = Agent(
    task="Search for the latest AI news and summarize the top 3 articles",
    llm=ChatOpenAI(model="gpt-4o")
)
result = await agent.run()

Browser Controller ​

The Browser module provides an abstraction layer over Playwright and handles the actual browser automation. It performs operations such as:

  • Managing browser lifecycle (creation, navigation, closing)
  • Executing page actions (clicks, typing, scrolling)
  • Capturing page content and element information
  • Handling browser events and states
  • Managing multiple tabs and windows

DOM Processor ​

The DOMProcessor is responsible for parsing and processing the Document Object Model (DOM) of web pages. Its main functions include:

  • Converting raw HTML into structured data
  • Identifying and labeling interactive elements
  • Filtering and prioritizing page content
  • Simplifying complex DOM structures for language model consumption
  • Providing context about page structure and content

Action System ​

The action system defines a set of operations that can be performed on web pages. These actions include:

  • Navigation (go to URL, back, forward)
  • Interaction (click, type, select)
  • Extraction (get text, get attributes)
  • Page control (wait, scroll, focus)
  • Tab management (new tab, switch tab, close tab)

Each action is defined with parameters, pre-conditions, and post-conditions to ensure proper execution.

Language Model Interface ​

This component manages communication with the language model, which is responsible for:

  • Understanding task requirements
  • Planning sequences of browser actions
  • Making decisions based on page content
  • Interpreting results from actions
  • Generating natural language responses

Memory System (Optional) ​

The optional memory component allows agents to maintain context across actions and pages:

  • Session memory for short-term task execution
  • Persistent memory for long-running tasks
  • Structured storage of key information from pages
  • Context retrieval to inform future actions

Execution Flow ​

When a task is executed, Browser-Use follows this general flow:

  1. Task Initialization: The user provides a natural language task description and initializes the Agent.

  2. Planning Phase: The language model analyzes the task and creates a high-level plan of actions.

  3. Browser Initialization: The browser is launched and configured according to the specified options.

  4. Execution Loop:

    • Current page state is captured and processed
    • Page state is sent to the language model
    • The language model decides on the next action
    • The action is executed in the browser
    • Results are collected and stored in memory (if enabled)
    • This loop continues until the task is complete

  5. Completion: The final result is generated, the browser is closed, and the result is returned to the user.

Error Handling ​

Browser-Use implements several error handling mechanisms:

  • Automatic Retry: Failed actions are automatically retried with configurable limits
  • Adaptive Recovery: The system can adapt to unexpected page states
  • Graceful Degradation: If certain capabilities are unavailable, the system falls back to alternatives
  • Detailed Logging: Comprehensive logs help with debugging and troubleshooting

Extension Points ​

Browser-Use is designed to be extensible in several ways:

  • Custom Actions: Define new browser actions for specific use cases
  • Alternative LLMs: Use different language models through a common interface
  • Custom Memory Systems: Implement specialized memory storage and retrieval
  • DOM Processing Plugins: Add custom DOM processing capabilities
  • Middleware: Insert custom logic at various points in the execution pipeline

Design Principles ​

The architecture follows these key principles:

  1. Abstraction: Hide browser automation complexity behind intuitive interfaces
  2. Modularity: Components can be used independently and extended easily
  3. Robustness: Handle unpredictable web environments gracefully
  4. Context Awareness: Maintain and leverage context for intelligent decision-making
  5. Human-like Interaction: Focus on natural, human-like browser interaction patterns