AIPayHQ.com · Page 3 · The Complete Agentic Payment Stack
MCP + x402 + IBA
Three Open Standards · One Authorization Layer · Complete Agentic Commerce
LAYER 1
MCP
Tool access
→
LAYER 2
x402
Payment mechanics
→
LAYER 3
IBA
Authorization gate
MCP gives the agent the tools.
x402 executes the payment.
IBA declares what the agent was authorized to do before it touched either.
Without IBA beneath MCP, any tool is available to any agent that connects.
The payment tool. The file tool. The credential tool. No cryptographic boundary between them.
4
MCP Tools Available
1
IBA Certs Active
0
Authorized Calls
0
Blocked at Gate
$0
Saved by IBA
01
MODEL CONTEXT PROTOCOL
MCP — The Tool Layer
Anthropic’s open protocol connecting AI agents to external tools and services. The agent connects to an MCP server. Tools become available: payment, file, data, API. The agent can call any available tool.
GAP: MCP makes tools available. It does not declare which tools the agent is authorized to invoke, or under what conditions.
02
HTTP PAYMENT PROTOCOL
x402 — The Payment Layer
Coinbase’s open protocol enabling autonomous agent payments via HTTP 402. When the agent encounters a paywall, x402 executes the payment using stablecoins. Sub-second. Autonomous. No human confirmation.
GAP: x402 executes payments efficiently. It does not declare what the agent may pay for, the authorized payee list, or the maximum spend.
03
IBA INTENT BOUND AUTHORIZATION
IBA — The Authorization Gate
A signed human intent certificate declared before MCP tools are invoked. Authorized tools. Permitted payees. Maximum spend. Hard limits. The gate is set before the agent connects. Nothing outside the certificate executes.
CLOSES: The authorization gap beneath both MCP and x402. The certificate is the cryptographic contract between the human and the agent.
LIVE MCP SERVER · AGENT CONNECTED · IBA CERT ACTIVE
MCP ONLINE
PAYMENT TOOL
IBA GOVERNED
DATA TOOL
IBA GOVERNED
FILE TOOL
NOT IN CERT
CREDENTIAL TOOL
HARD LIMIT BLOCKED
✕ WITHOUT IBA — UNGOVERNED AGENT
MCP connected. All tools available.
No certificate. No declared scope.
Awaiting instruction — any tool can be called.
✓ WITH IBA — GOVERNED AGENT
MCP connected. IBA cert loaded.
Authorized: payment tool, data tool.
Hard limits active. Gate enforcing.
ATTACK SCENARIOS · MCP + x402 · WITH AND WITHOUT IBA
MCP + x402 + IBA · ATTACK INTERCEPT
UNAUTHORIZED CALL BLOCKED