Plasmate, developed by Plasmate Labs, is a free MCP server and agent-native headless browser engine built in Rust. It processes web pages into a Semantic Object Model (SOM), a structured representation designed for direct reasoning by AI agents and LLMs. This tool runs JavaScript via V8 and offers a suite of capabilities for web page comprehension, automated interaction, and content monitoring. Plasmate aims to provide AI agents with a direct way to understand and operate on web content.

What does Plasmate connect to?

Plasmate connects to the web to process HTML content, generating a Semantic Object Model. It supports stdio as a transport protocol for its MCP tool server. For its Agent Web Protocol (AWP) and Chrome DevTools Protocol (CDP) compatibility servers, Plasmate uses WebSocket. Its hosted SOM Cache API works with any HTTP client. Confirmed AI clients include Claude Desktop and VS Code Copilot, while frameworks like LangChain and CrewAI are compatible via SDKs.

Core features and tools

Plasmate offers several callable tools when run as an MCP tool server, including fetch_page for structured SOM, extract_text for clean text, and extract_links for deduplicated links. It also provides crawl_policy to evaluate robots.txt, and inspect_page for bounded SOM. Its native AWP core includes page navigation and interaction actions like click and type. A subset of CDP methods is also supported, such as page.goto() and Runtime.evaluate.

Who is it for?

Plasmate is primarily for AI agents and LLMs, along with developers building AI agents and AI frameworks. It helps these systems acquire structured web data and perform supervised web interactions. The tool is designed to reduce token usage by providing a reasoned Semantic Object Model instead of raw HTML. Its capabilities support advanced automation for web-based tasks. Skip this if your primary need is manual web browsing without AI agent integration.

How to get started

Access is granted through a standard OAuth authorization flow. Authenticated browsing requires exporting cookies using a dedicated Chrome extension.

Use cases

• AI agents can fetch web pages and receive a structured Semantic Object Model (SOM) output for reasoning.
• Agents can execute supervised stateful workflows to navigate, observe, and interact with web pages using AWP.
• Plasmate can be integrated into CI/CD pipelines to fetch web pages and output SOM JSON for content monitoring.

Plasmate by Plasmate Labs is a powerful MCP server designed to enable AI agents to interact with and understand the web. Its ability to convert HTML into a Semantic Object Model significantly aids AI reasoning and efficiency. The tool supports various protocols and offers specific mechanisms for authenticated browsing and secure operations.