Site tools are ChatGPT’s implementation of the proposed WebMCP standard. With WebMCP, a website can offer useful actions directly to an AI agent alongside the interface people already use. You and the agent can work with the same live page and signed-in session.
In the built-in browser in the ChatGPT desktop app, ChatGPT Work and Codex can discover and use these tools when they are available.
Use GPT-5.6 Sol or GPT-5.6 Terra for site tools. GPT-5.6 Luna currently has WebMCP disabled. Update the ChatGPT desktop app to the latest version. Site tools aren’t available in Enterprise or Edu workspaces. Availability also depends on rollout and the tools provided by the current page.
WebMCP vs. MCP
Model Context Protocol (MCP) connects an AI application to a local or remote server. Its tools can work independently of an open webpage, such as searching a service or managing records through an API.
WebMCP lets a website make its capabilities available to an agent as a set of predefined tools. The agent can discover them when it visits, so people don’t need to install a separate MCP server or set up another connection to use those capabilities.
This approach is useful when you and the agent need to see the same thing, such as when editing a canvas or exploring a dashboard. A plugin with an MCP server can provide an integration that works independently of an open page. A website can support both.
How it works in the browser
Open a website in the built-in browser and ask ChatGPT Work or Codex to help with a task. If the page offers site tools, the agent can discover and use the relevant actions in the website you’re viewing. For example, a document editor might let the agent find a section or leave a comment for you to review.
Select Site tools in the browser’s address bar to see what the website provides. Choose Available site tools to inspect the individual tools. The browser checks each request before the website carries it out, and the agent can inspect the page to see what changed. When recent activity is available, choose Recently used to open Sources and review those calls.
In this example, expand Available site tools to inspect the tools provided by Margin.
Tools belong to the page that provides them. Closing or navigating away from a page can make its tools unavailable. If no suitable tool is available, the agent may still be able to use its regular browser capabilities.
Example: Explore OpenAI documentation
ChatGPT Learn and OpenAI Developers offer site tools for finding and reading documentation. Select Open in ChatGPT in the composer to open Learn in the desktop app’s browser beside a new chat with this prompt ready to send.
The agent can use these tools to search, read, and open the relevant page:
| Tool | What it does |
|---|---|
search_openai_docs | Searches OpenAI documentation. |
lookup_page | Reads a documentation page by path or URL. |
lookup_context | Reads the current docs route and selected text. |
navigate_to_page | Opens a matching page on the current documentation site. |
generate_custom_guide | Starts a custom build or learning guide and returns its status and link. |
Docs Agent generates a custom guide asynchronously. Receiving its link doesn’t mean generation has finished.
Security and user controls
Website-provided tool definitions and results are untrusted content. A tool’s name or claim that it only reads data isn’t proof of what it does. Website instructions don’t give the agent permission to share unrelated information or take sensitive actions.
In the built-in browser, each tool invocation receives a safety review before it runs. Normal website-access and confirmation policies still apply, including for consequential actions such as sending messages, making purchases, deleting data, or changing permissions. The browser ties each invocation to its originating page and tool registration. These checks reduce risk; they don’t make a website or its output trustworthy.
You can turn off Enable site tools in Settings > Browser > Permissions. Review the site, requested action, and result before sharing sensitive information or relying on a change.
Report security vulnerabilities through OpenAI’s Security Bug Bounty program. For AI safety risks, see the Safety Bug Bounty program. Follow each program’s scope and submission instructions.
Add WebMCP to your website
You can ask Codex to add WebMCP support to the web app or Site you’re working on. Describe what an agent should be able to do, and ask Codex to reuse the application’s existing logic and permissions.
Start with an operation your application already supports. For example:
- A dashboard that lets the agent set a date range and inspect the data behind a chart.
- A document editor that lets the agent find a section, suggest an edit, or leave a comment for you to review.
- A travel planner that lets the agent compare options and update an itinerary while you inspect the map.
You can also write the code yourself. In your page’s JavaScript module, check for browser support and register a tool. This read-only example returns the current page’s title:
if (typeof document.modelContext?.registerTool === "function") {
await document.modelContext.registerTool({
name: "get_page_title",
description: "Read the title of the current page.",
inputSchema: {
type: "object",
properties: {},
additionalProperties: false,
},
annotations: { readOnlyHint: true },
execute: async () => ({ title: document.title }),
});
}A compatible agent can discover get_page_title and receive the page’s
current title. For a tool that accepts arguments, describe them in the input
schema and use them in the execute handler to call your application’s
existing logic.
Keep inputs narrow, describe side effects, and return enough information to verify the result. Use your application’s existing authentication, authorization, and input validation. Preserve the normal interface for people and browsers that don’t support WebMCP.
For API details and examples, see the WebMCP specification and Chrome’s developer guide.