A2A 1.0 · UCP 2026-04-08 · MCP 2025-11-25

One seller gateway. Three agent-native protocol doors.

ASG lets buyer agents discover a business, exchange structured messages, create checkout sessions, call commerce tools, and continue into seller-controlled checkout systems without making WebsDocs the merchant of record or custodian of funds.

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A2A 1.0

Agent communication

Agent Card discovery, message send and streaming, task state, subscriptions, and push configuration.

/ai/{clientSlug}/a2a/message:send

UCP 2026-04-08

Commerce routing

Business capability discovery and checkout-session routing toward the seller's own checkout backend or secure continuation URL.

/ai/{clientSlug}/ucp/v1/checkout-sessions

MCP 2025-11-25

Commerce tools

Streamable HTTP JSON-RPC with UCP checkout tools: create, get, update, complete, and cancel checkout.

/ai/{clientSlug}/ucp/mcp

Neutral routing boundary

ASG routes the transaction conversation—not the money.

The seller remains merchant of record.
ASG rejects raw PAN, CVV and CVC data.
Opaque payment tokens or mandates may be relayed without being stored.
Payment authorization and settlement remain with the buyer, seller, PSP and financial institution.

Published seller route patterns

/.well-known/agent-card.json/.well-known/ucp/a2a/message:send/a2a/message:stream/ucp/v1/checkout-sessions/ucp/mcp

Machine-readable protocol advertisement

{
  "ok": true,
  "type": "websdocs_asg_protocol_advertisement",
  "product": "WebsDocs AI Sales Gateway",
  "position": "Neutral buyer-agent to seller routing infrastructure",
  "versions": {
    "a2a": "1.0",
    "ucp": "2026-04-08",
    "mcp": "2025-11-25"
  },
  "publicGuides": {
    "human": "https://aig.websdocs.com/protocols",
    "json": "https://aig.websdocs.com/api/protocols",
    "directory": "https://aig.websdocs.com/directory",
    "directoryJson": "https://aig.websdocs.com/api/directory",
    "a2aGuide": "https://aig.websdocs.com/api/a2a",
    "llms": "https://aig.websdocs.com/llms.txt"
  },
  "sellerPattern": {
    "gateway": "https://aig.websdocs.com/ai/{clientSlug}",
    "agentCard": "https://aig.websdocs.com/ai/{clientSlug}/.well-known/agent-card.json",
    "a2aMessageSend": "https://aig.websdocs.com/ai/{clientSlug}/a2a/message:send",
    "a2aMessageStream": "https://aig.websdocs.com/ai/{clientSlug}/a2a/message:stream",
    "ucpProfile": "https://aig.websdocs.com/ai/{clientSlug}/.well-known/ucp",
    "ucpCheckout": "https://aig.websdocs.com/ai/{clientSlug}/ucp/v1/checkout-sessions",
    "ucpMcp": "https://aig.websdocs.com/ai/{clientSlug}/ucp/mcp"
  },
  "capabilities": {
    "a2a": [
      "agent discovery",
      "message send",
      "message streaming",
      "task management",
      "push notification configuration"
    ],
    "ucp": [
      "business capability discovery",
      "checkout session create/read/update",
      "completion request",
      "cancellation",
      "seller continuation URL"
    ],
    "mcp": [
      "initialize",
      "ping",
      "tools/list",
      "tools/call",
      "UCP checkout tools over Streamable HTTP JSON-RPC"
    ]
  },
  "commercialBoundary": {
    "merchantOfRecord": "seller",
    "fundsCustody": false,
    "rawCardDataAccepted": false,
    "paymentAuthorization": "buyer, seller, payment service provider, and financial institution",
    "asgRole": "discover, validate, route, log, and relay protocol responses"
  }
}