Getting started
- Connect to the MCP adapter at
x402.agkit.io/mcp/using streamable-http transport. - Authenticate by passing your API token as the
auth_tokenparameter on every tool call. - Browse the catalog using the free endpoints below — no payment needed.
- Call gated endpoints by including a
payment_proof,bypass_token, orcredit_account_org_slug.
Free endpoints
These MCP tools require authentication but no payment.
| Tool | Description |
|---|---|
list_product_groups | Browse all product groups for a tenant |
get_product_group | Get a product group with nested catalog items |
get_config_version | Check current config version number |
get_config_blob | Get full config JSON for a tenant |
Gated endpoints
These tools require payment. Calling without payment returns a 402 response with the price.
| Tool | Price | Description |
|---|---|---|
get_catalog_item | 0.0001 USDC | Read catalog item details |
list_catalog_items | 0.0001 USDC | Browse catalog items |
create_product_group | 0.0001 USDC | Create a new product group |
The 402 response
When a gated endpoint is called without payment, the gate returns a 402 with payment requirements:
{
"status": 402,
"tool": "get_catalog_item",
"price": "0.0001",
"currency": "USDC",
"network": "base",
"pay_to": "0xabc...def",
"accepts": ["exact-evm"],
"description": "Read catalog item details"
}
The agent signs a payment payload off-chain (no transaction submitted yet) and retries the request with a PAYMENT-SIGNATURE header. The gate verifies the signature via the facilitator, fulfills the request, then the facilitator settles the payment on-chain. x402 does not transfer funds — it coordinates verification and settlement through the facilitator.
Access methods
Three ways to access gated endpoints:
| Method | Parameter | Use case |
|---|---|---|
| Payment proof | payment_proof | x402 protocol payment (agent pays per call) |
| Bypass token | bypass_token + endpoint_slug | Prepaid access for known customers |
| Credit account | credit_account_org_slug + endpoint_slug | Pay-as-you-go USD balance |