WebMCP

Where it applies

Two places register tools:

That is what "WebMCP ready" on the landing means, and all it means.

Use with your AI assistant

There are two ways to submit a response:

• From your app: use the Form's API key with the HTTP API or SDK.
• From an open browser tab: open the public survey with a WebMCP-aware browser agent. It can read the Fields and submit through the page's tools. You do not need to paste the Form's API key into your assistant.

For ChatGPT, Claude or Gemini, check the browser or client you are using. Opening a link in an assistant does not automatically enable WebMCP; the browser agent must support it. The normal form remains usable without it.

To work with Forms and responses outside an open tab, use the remote MCP setup guide. Remote MCP uses a Workspace token, not the public Form API key. Client support and authentication options vary; Gemini CLI is an example of an MCP client in the Gemini family.

What it is

WebMCP is a draft from the W3C Web Machine Learning CG. The page registers tools on document.modelContext. The spec moved the getter from navigator to document in May 2026; Noonmark reads both. The browser's agent discovers and calls those functions in the tab, with the person watching.

It is not Anthropic's MCP on the wire. It replaces neither the SDK, the HTTP ingest nor a remote MCP server. Without a tab on the origin, there is nothing to discover.

What Noonmark registers

Public survey pages — /f/:handle — register two tools, with feature detection. A feedback Form has no page on Noonmark: the screen lives in your own app, so the POST via SDK or HTTP remains the path.

await modelContext.registerTool({
  name: "describe_form",
  description: "Returns this survey's name and Field list.",
  inputSchema: { type: "object", properties: {} },
  annotations: { readOnlyHint: true },
  execute() {
    return { name, kind: "survey", fields };
  },
});

await modelContext.registerTool({
  name: "submit_form",
  description: "Submit this survey. Keys match Field.key.",
  inputSchema: fieldInputSchema(fields),
  async execute(input) {
    const response = await fetch(`/api/v1/f/${encodeURIComponent(apiKey)}/page`, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify(input),
    });
    return response.json();
  },
});

Success and error appear on the page, so the person can see what the agent did. Rate limits and Field 400s stay the same.

Field → JSON Schema

The Field's key is the property. The label becomes the description.

In the Studio

A signed-in Studio tab registers the MCP server's five reads, with the same names, inputs and answers, plus the person's Workspaces and five writes. They act as the person signed in, on the Workspace that is open.

Every write is marked consequentialHint and waits on the person: the Studio shows what the agent asked for — the Submission and the word, the Form and every Field, the Workspace by name — and only Confirm makes the change. Decline, Escape or the agent cancelling all leave things as they were. A status change lands on the Timeline under the person's name, the same as the status menu. Fields go through the same checks as the Form editor.

The two Submission reads carry untrustedContentHint: a payload is whatever a stranger typed, and an agent should read it as data, not instructions.

What stays out of the tools

Nothing that deletes or reconfigures: rotating the API key, deleting a Form or a Submission, creating or deleting webhooks, Integrations, the slug, tokens. Those stay clicks.

Headless agents (a script, a GitHub Action, another server) use POST /api/v1/submit. WebMCP is not for that.

A widget on another origin

The tools Permissions Policy defaults to self. A cross-origin iframe only registers tools if the embed carries allow="tools" — see Embed a Form. HTTPS is required (Secure Context).

The page must also be origin-keyed: WebMCP is disabled when document.domain is enabled, for example by Origin-Agent-Cluster: ?0. A site can opt out entirely with Permissions-Policy: tools=(). Noonmark sends neither header.