Your x402 stack already settles. Add one field and it also signs.

AgentCore, Crossmint, Skyfire, LangChain, CrewAI — every framework that emits x402 payments already carries the wire for agent identity. One extra field (X-Hive-Birth-Cert-Id) ties every settlement to a dual-signed W3C DID. Counterparties verify provenance without a round-trip. $0.01 at agent spawn.

How it works in three steps

Wire format: one extra header

The complete integration change to an existing x402 request is one header line. Nothing else in your payment flow changes.

POST /api/v1/some-paid-tool HTTP/1.1
Host: your-counterparty.com
Content-Type: application/json
x402-payment: <base64url-encoded-payment-proof>
X-Hive-Birth-Cert-Id: 73c70e04-afdf-4025-b6f9-24337af0c895

{
  "query": "What is the NAV of QBTS today?"
}

The X-Hive-Birth-Cert-Id header is a standard UUID string. It references a birth certificate issued at agent spawn time. No cryptographic material is embedded in the header itself — verification is delegated to /v1/birth/verify.

Try it in 60 seconds

Issue a sample birth certificate for your agent now. No account, no API key, no SDK install. Free sample tier: 30 requests per hour per IP.

curl -s -X POST https://hivemorph.onrender.com/v1/birth/issue/sample \
  -H "Content-Type: application/json" \
  -d '{
    "agent_name": "my-trading-agent",
    "model_family": "claude-3-5-sonnet",
    "training_cutoff": "2024-04",
    "controller_did": "did:key:z6MkhaXgBZDvotDkL5257faiztiGiC2QtKLGpbnnEGta2doK"
  }'

import requests

resp = requests.post(
    "https://hivemorph.onrender.com/v1/birth/issue/sample",
    json={
        "agent_name": "my-trading-agent",
        "model_family": "claude-3-5-sonnet",
        "training_cutoff": "2024-04",
        "controller_did": "did:key:z6MkhaXgBZDvotDkL5257faiztiGiC2QtKLGpbnnEGta2doK",
    },
)
cert = resp.json()

# Use this id in every subsequent x402 request
birth_cert_id = cert["birth_cert_id"]
did_hive_id = cert["did_hive_id"]

# Attach to your x402 request
headers = {
    "x402-payment": "<your-payment-proof>",
    "X-Hive-Birth-Cert-Id": birth_cert_id,
}
print(f"Agent DID: {did_hive_id}")
print(f"Cert ID:   {birth_cert_id}")

const resp = await fetch(
  "https://hivemorph.onrender.com/v1/birth/issue/sample",
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      agent_name: "my-trading-agent",
      model_family: "claude-3-5-sonnet",
      training_cutoff: "2024-04",
      controller_did: "did:key:z6MkhaXgBZDvotDkL5257faiztiGiC2QtKLGpbnnEGta2doK",
    }),
  }
);
const cert = await resp.json();
const { birth_cert_id, did_hive_id } = cert;

// Attach to every outbound x402 request
const headers = {
  "x402-payment": "<your-payment-proof>",
  "X-Hive-Birth-Cert-Id": birth_cert_id,
};
console.log("Agent DID:", did_hive_id);
console.log("Cert ID:  ", birth_cert_id);

What the birth certificate envelope contains

Signal value per x402 framework

did:hive — registered W3C DID method

did:hive is a registered W3C DID method. Agent DIDs take the form did:hive:agent:<short_uuid>. DID documents are resolvable at https://hivemorph.onrender.com/v1/did/resolve/<did>. The signing key pair uses Ed25519 today. ML-DSA-65 (NIST FIPS 204) keys will be added to the DID document when the production tier activates full post-quantum coverage, enabling dual-verification against both classical and lattice algorithms without changing the did:hive identifier.