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What is the manifest?

The WebMCP manifest is a JSON file published at /.well-known/webmcp.json on every OpenHermit-enabled website. It’s the machine-readable equivalent of a phone book — it tells AI agents exactly what your website can do and how to do it. AI agents (and any HTTP client) can fetch it directly: 
curl https://yourwebsite.com/.well-known/webmcp.json

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Manifest structure

{
  "webmcp_version": "1.0",
  "site": {
    "name": "Acme Corp",
    "domain": "acme.com",
    "description": "We build the best widgets in Switzerland.",
    "agent_instructions": "This website has 2 agent-ready actions. Use contact_form to reach the team or book_consultation to schedule a call."
  },
  "actions": [
    {
      "name": "Contact Form",
      "type": "contact_form",
      "tool_name": "contact_form",
      "description": "Send a message to the Acme Corp team",
      "selector": "#contact-form",
      "page_url": "https://acme.com/contact",
      "enabled": true,
      "before_prompt": "Please have the customer's name, email, and question ready.",
      "success_prompt": "Message sent. The team responds within 24 hours.",
      "failure_prompt": "Try emailing hello@acme.com directly.",
      "next_action": {
        "url": "https://calendly.com/acme/30min",
        "label": "Book a meeting"
      },
      "fields": [
        { "name": "name", "type": "text", "required": true },
        { "name": "email", "type": "email", "required": true },
        { "name": "message", "type": "textarea", "required": true }
      ]
    }
  ]
}

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How agents find the manifest

OpenHermit makes your manifest discoverable in four ways: 1. Standard path — /.well-known/webmcp.json (the canonical location any agent can check) 2. Meta tag — injected into every page’s <head>: 
<meta name="webmcp" content="https://openhermit.com/api/manifest?key=YOUR_KEY" />
3. Link tag — also in <head>: 
<link rel="webmcp" href="https://openhermit.com/api/manifest?key=YOUR_KEY" />
4. Response header — on every page response: 
X-WebMCP: enabled

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View your manifest

You can view your manifest anytime from the website detail page in the dashboard, or directly at: 
https://openhermit.com/api/manifest?key=YOUR_API_KEY

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Disabled actions

Only actions marked as Active in your dashboard appear in the manifest. Disabled actions are hidden from agents entirely. Use this to temporarily remove an action without deleting it.

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The agent_instructions field

The site.agent_instructions string is a plain-text summary generated automatically from your active actions. Agents that read this first get a high-level understanding of what’s available before parsing individual actions. You can see and customise this in the website detail page (coming soon).