Agentic Web — MCP Server Profile

The Agentic Web specification is an MCP Server Profile — a set of conventions for implementing any business's endpoint as a standard MCP server. It is not a separate protocol. Any MCP-compatible client (Claude, ChatGPT, custom agents) can connect without special adapters.

Architecture

The agentic web follows a three-party interaction model:

Users interact with AI agents which connect to vendor MCP servers over Streamable HTTP. The vendor exposes tools through the standard MCP protocol — including tools for answering questions, taking actions, and qualifying buyers. The vendor maintains full control over responses, qualification logic, and available capabilities.

Key Capabilities

Agentic Web servers use Streamable HTTP — the MCP transport where a single HTTPS endpoint accepts JSON-RPC 2.0 messages via POST. Responses may be returned as a single JSON body or streamed via Server-Sent Events (SSE).

Endpoint

The vendor exposes a single MCP endpoint, for example:

POST https://acme.com/mcp
Content-Type: application/json
Accept: application/json, text/event-stream

All MCP methods (initialize, tools/list, tools/call, etc.) are sent to this single URL.

Initialize Handshake

Every session begins with an initialize request. The client declares its supported protocol version and capabilities, and the server responds with its own:

// Client → Server
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2025-03-26",
    "capabilities": {},
    "clientInfo": {
      "name": "claude-desktop",
      "version": "1.0.0"
    }
  }
}

// Server → Client
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "protocolVersion": "2025-03-26",
    "capabilities": {
      "tools": { "listChanged": true }
    },
    "serverInfo": {
      "name": "acme-agentic-web",
      "version": "1.0.0"
    }
  }
}

Session Management

After initialize, the server returns an Mcp-Session-Id header. The client includes this header on all subsequent requests to maintain session state:

POST https://acme.com/mcp
Content-Type: application/json
Mcp-Session-Id: sess_a1b2c3d4e5f6

Vendor actions are exposed as MCP tools. Agents discover them via tools/list and invoke them via tools/call. Each tool includes a full JSON Schema inputSchema so agents know exactly what parameters to provide.

Required, optional, and custom tools

Listing Tools

// Client → Server
{
  "jsonrpc": "2.0",
  "id": 4,
  "method": "tools/list",
  "params": {}
}

// Server → Client
{
  "jsonrpc": "2.0",
  "id": 4,
  "result": {
    "tools": [
      {
        "name": "ask_question",
        "description": "Ask a free-form question about Acme's products, pricing, integrations, or compliance",
        "inputSchema": {
          "type": "object",
          "properties": {
            "question": { "type": "string", "description": "The question to ask" }
          },
          "required": ["question"]
        }
      },
      {
        "name": "schedule_demo",
        "description": "Book a product demo with a sales representative",
        "inputSchema": {
          "type": "object",
          "properties": {
            "preferred_times": {
              "type": "array",
              "items": { "type": "string", "format": "date-time" },
              "description": "ISO 8601 preferred meeting times"
            },
            "timezone": { "type": "string", "description": "IANA timezone (e.g. America/New_York)" },
            "topics": {
              "type": "array",
              "items": { "type": "string" },
              "description": "Topics to cover in the demo"
            }
          },
          "required": ["preferred_times", "timezone"]
        }
      },
      {
        "name": "qualify",
        "description": "Submit buyer qualification data to unlock gated actions",
        "inputSchema": { /* see Section 5 */ }
      }
    ]
  }
}

Standard Tools

Calling a Tool

// Client → Server
{
  "jsonrpc": "2.0",
  "id": 5,
  "method": "tools/call",
  "params": {
    "name": "ask_question",
    "arguments": {
      "question": "Does Acme support Salesforce integration?"
    }
  }
}

// Server → Client
{
  "jsonrpc": "2.0",
  "id": 5,
  "result": {
    "content": [
      {
        "type": "text",
        "text": "Yes, Acme offers native Salesforce integration on all paid plans. Setup takes approximately 15 minutes with our guided wizard."
      }
    ],
    "structuredContent": {
      "answer": "Yes, Acme offers native Salesforce integration on all paid plans.",
      "confidence": 1.0,
      "sources": [
        {
          "type": "documentation",
          "url": "https://docs.acme.com/integrations/salesforce"
        }
      ],
      "suggestedActions": ["schedule_demo", "start_trial"],
      "verification": {
        "algorithm": "Ed25519",
        "keyId": "acme-2025-03",
        "signature": "base64-encoded-signature..."
      }
    }
  }
}

Small Business Example

The same protocol powers small businesses too. Here's how Rosa's Bakery handles a customer question through an AI agent:

// Client → Server (ask about a gluten-free cake)
{
  "jsonrpc": "2.0",
  "id": 11,
  "method": "tools/call",
  "params": {
    "name": "ask_question",
    "arguments": {
      "question": "Can I order a gluten-free birthday cake for Saturday?"
    }
  }
}

// Server → Client
{
  "jsonrpc": "2.0",
  "id": 11,
  "result": {
    "content": [
      {
        "type": "text",
        "text": "Yes! Rosa's Bakery offers gluten-free Vanilla Bean cakes in 6-inch ($30) and 8-inch ($42) sizes. We need 48 hours notice for custom orders, so Saturday pickup is available if you order by Thursday."
      }
    ],
    "structuredContent": {
      "answer": "Gluten-free Vanilla Bean cakes available in 6-inch and 8-inch sizes.",
      "confidence": 1.0,
      "availability": {
        "glutenFree": "true",
        "sizes": ["6-inch", "8-inch"],
        "pricing": { "6-inch": 30, "8-inch": 42 },
        "leadTime": "48 hours",
        "saturdayPickup": "available if ordered by Thursday"
      },
      "suggestedActions": ["place_order", "view_menu"],
      "verification": {
        "algorithm": "Ed25519",
        "keyId": "rosas-2025-06",
        "signature": "base64-encoded-signature..."
      }
    }
  }
}

The qualify tool enables progressive, conversational data collection. Vendors can gate pricing, quotes, and demo scheduling behind qualification — collecting buyer context through multiple rounds of interaction within a single MCP session.

Session States

The qualify Tool

// Client → Server: submit qualification data
{
  "jsonrpc": "2.0",
  "id": 6,
  "method": "tools/call",
  "params": {
    "name": "qualify",
    "arguments": {
      "company_name": "Globex Corporation",
      "company_size": "500-1000",
      "use_case": "API platform for internal tooling",
      "email": "buyer@globex.com"
    }
  }
}

// Server → Client: qualification incomplete, more data needed
{
  "jsonrpc": "2.0",
  "id": 6,
  "result": {
    "content": [
      {
        "type": "text",
        "text": "Thanks! I have your company info. To provide accurate pricing, I also need your expected monthly API volume and deployment preference."
      }
    ],
    "structuredContent": {
      "status": "qualifying",
      "collected": ["company_name", "company_size", "use_case", "email"],
      "remaining": [
        {
          "field": "monthly_api_volume",
          "type": "select",
          "options": ["under-10k", "10k-100k", "100k-1m", "1m+"],
          "description": "Expected monthly API calls"
        },
        {
          "field": "deployment",
          "type": "select",
          "options": ["cloud", "on-premise", "hybrid"],
          "description": "Deployment preference"
        }
      ]
    }
  }
}

Gated Content

When an agent requests gated content before qualifying, the server includes a qualificationRequired flag:

// Server → Client: gated resource response
{
  "jsonrpc": "2.0",
  "id": 7,
  "result": {
    "content": [
      {
        "type": "text",
        "text": "Pricing details require qualification. Please provide your information using the qualify tool."
      }
    ],
    "structuredContent": {
      "qualificationRequired": true,
      "reason": "Pricing details require company information",
      "requiredFields": ["company_name", "company_size", "email"]
    }
  }
}

Verified responses use Ed25519 signatures over JCS-canonicalized structuredContent. This lets agents cryptographically confirm that data came directly from the vendor and hasn't been tampered with.

Signature Format

Every tool result that includes structuredContent can carry a verification object:

"verification": {
  "algorithm": "Ed25519",
  "keyId": "acme-2025-03",
  "signature": "base64url-encoded-Ed25519-signature",
  "timestamp": "2025-03-15T10:30:00Z"
}

Public Key Distribution

Vendors publish their public keys at /.well-known/jwks.json following RFC 7517 (JSON Web Key Set):

// GET https://acme.com/.well-known/jwks.json
{
  "keys": [
    {
      "kty": "OKP",
      "crv": "Ed25519",
      "kid": "acme-2025-03",
      "x": "base64url-encoded-public-key",
      "use": "sig"
    }
  ]
}

Verification Steps

1. Extract the structuredContent object from the tool result (excluding the verification field itself).
2. Canonicalize the object using JCS (RFC 8785 — JSON Canonicalization Scheme) to produce a deterministic byte string.
3. Fetch the vendor's public key from /.well-known/jwks.json, matching by keyId → kid.
4. Verify the Ed25519 signature over the canonicalized bytes using the matched public key.
5. Check that the timestamp is within an acceptable window (recommended: 5 minutes).

The Agentic Web works like a website: anyone can visit and ask questions without logging in. Authentication is only required when a user needs access to their own account data or performs sensitive actions tied to an existing relationship.

Three tiers of access

Anonymous access (default)

Most interactions require no authentication. An agent connects, calls initialize, and immediately starts using ask_question. The Mcp-Session-Id header provides continuity across requests but does not identify the user.

// No auth headers needed — just connect and ask
POST https://acme.com/mcp
Content-Type: application/json
Mcp-Session-Id: sess_a1b2c3d4e5f6

{
  "jsonrpc": "2.0",
  "id": 5,
  "method": "tools/call",
  "params": {
    "name": "ask_question",
    "arguments": {
      "question": "What are your pricing plans?"
    }
  }
}

Qualified access (via the qualify tool)

When the server needs buyer context before unlocking certain tools, it returns a qualificationRequired flag (see Section 4). The agent collects information conversationally and submits it via the qualify tool. This is not OAuth — it's a structured conversation within the same session.

After qualification, the session unlocks gated tools like schedule_demo and request_quote. No tokens, no login screens, no redirect flows. The vendor has the buyer's info because the buyer chose to share it.

Authenticated access (optional)

Some vendors may offer tools that require knowing who the user is — viewing their own support tickets, managing a subscription, or accessing account-specific data. For these cases, the server can require OAuth 2.1 authentication per the MCP spec.

When a tool requires authentication, the server responds with 401 and the standard MCP OAuth flow begins:

// Server responds 401 for account-specific tools
HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer resource_metadata="https://acme.com/.well-known/oauth-protected-resource"

// After OAuth, requests include a Bearer token
POST https://acme.com/mcp
Authorization: Bearer eyJhbGciOiJFZDI1NTE5...
Mcp-Session-Id: sess_a1b2c3d4e5f6

{
  "jsonrpc": "2.0",
  "id": 8,
  "method": "tools/call",
  "params": {
    "name": "view_my_tickets",
    "arguments": {}
  }
}

Rate limiting

Vendors should protect their endpoints from abuse. Common approaches:

• IP-based rate limiting — standard web server configuration
• Session-based limits — cap requests per Mcp-Session-Id
• API keys — optional, issued to AI platforms for higher rate limits

When rate-limited, the server returns a standard JSON-RPC error with code -32000 and a Retry-After header.

Agentic Web

The ecosystem of AI-native endpoints implemented as MCP servers, enabling direct communication between AI agents and any business.

MCP Server Profile

A set of conventions for implementing a specific type of MCP server. The Agentic Web profile defines how any business exposes tools for AI agent interactions.

JSON-RPC 2.0

The message format used by MCP. Every request and response is a JSON-RPC 2.0 object with jsonrpc, method (or result/error), and id fields.

Streamable HTTP

The MCP transport used by this profile. A single HTTPS endpoint accepts JSON-RPC 2.0 messages via POST. Responses can be returned as JSON or streamed via Server-Sent Events.

Tool

An MCP primitive representing an action the agent can take (ask a question, schedule a demo, open a ticket). Discovered via tools/list, invoked via tools/call.

Session

A stateful MCP interaction tracked via the Mcp-Session-Id header. Sessions maintain qualification state, conversation context, and action history.

Qualification

Progressive buyer data collection via the qualify tool. Transitions the session from unqualified → qualifying → qualified, unlocking gated actions.

structuredContent

A typed, machine-readable object in tool results alongside the human-readable content array. Used for verification signatures, qualification status, and programmatic data.

Verified Response

A tool result whose structuredContent carries an Ed25519 signature, allowing agents to cryptographically verify that data came directly from the vendor.