Athena Browser MCP

An MCP server for browser automation that exposes semantic, token-efficient page representations optimized for LLM agents.

Motivation

LLM-based agents operate under strict context window and token constraints. However, most browser automation tools expose entire DOMs or full accessibility trees to the model.

This leads to:

• Rapid token exhaustion
• Higher inference costs
• Reduced reliability as relevant signal is buried in noise

In practice, agents spend more effort finding the right information than reasoning about it.

Athena exists to change the unit of information exposed to the model.

Core Idea: Semantic Page Snapshots

Instead of exposing raw DOM structures or full accessibility trees, Athena produces semantic page snapshots.

These snapshots are:

• Compact and structured
• Focused on user-visible intent
• Designed for LLM recall and reasoning, not DOM completeness
• Stable across layout shifts and DOM churn

The goal is not to mirror the browser, but to present the page in a form that aligns with how language models reason about interfaces.

How It Works

At a high level:

1. The browser is controlled via Playwright and CDP
2. The page is reduced into semantic regions and actionable elements
3. A structured snapshot is generated and sent to the LLM
4. Actions are resolved against stable semantic identifiers rather than fragile selectors

This separation keeps:

• Browser lifecycle management isolated
• Snapshots deterministic and low-entropy
• Agent reasoning predictable and efficient

Benchmarks

Early benchmarks against Playwright MCP show:

• ~19% fewer tokens consumed
• ~33% faster task completion
• Same or better success rates on common navigation tasks

Benchmarks were run using Claude Code on representative real-world tasks. Results are task-dependent and should be treated as directional rather than absolute.

What Athena Is (and Is Not)

Athena is:

• A semantic interface between browsers and LLM agents
• An MCP server focused on reliability and efficiency
• Designed for agent workflows, not test automation

Athena is not:

• A general-purpose browser
• A visual testing or screenshot framework
• A replacement for Playwright

Playwright remains the execution layer; Athena focuses on representation and reasoning.

Usage

Athena implements the Model Context Protocol (MCP) and works with:

• Claude Code
• Claude Desktop
• Cursor
• VS Code
• Any MCP-compatible client

Example workflows include:

• Navigating complex web apps
• Handling login and consent flows
• Performing multi-step UI interactions with lower token usage

See the examples/ directory for concrete agent workflows.

Installation

git clone https://github.com/lespaceman/athena-browser-mcp
cd athena-browser-mcp
npm install
npm run build

Configure the MCP server in your client according to its MCP integration instructions.

Architecture Overview

Athena separates concerns into three layers:

• Browser lifecycle — page creation, navigation, teardown
• Semantic snapshot generation — regions, elements, identifiers
• Action resolution — mapping agent intent to browser actions

This separation allows each layer to evolve independently while keeping agent-visible behavior stable.

Status

Athena is under active development. APIs and snapshot formats may evolve as real-world agent usage informs the design.

Feedback from practitioners building agent systems is especially welcome.

License

MIT