Proof of human, inside your agent.
You proved the payment. We prove the human. Any Claude, GPT or agent-framework session can register, issue a signed credential and check it — over the Model Context Protocol.
- Streamable HTTP
- Auth: Bearer <5arz API key>
- Free: 1,000 seals/mo
- Verify against the public JWKS, no SDK
- x402 task purchase — no key (developer preview)
Add it to Claude.
One command in Claude Code, or one block in any MCP client config.
claude mcp add --transport http 5arz https://mcp.5arz.com \
--header "Authorization: Bearer arz_live_YOUR_KEY"
.mcp.json / Claude Desktop)
{
"mcpServers": {
"5arz": {
"type": "http",
"url": "https://mcp.5arz.com",
"headers": { "Authorization": "Bearer arz_live_YOUR_KEY" }
}
}
}
register_agent, get_vhh_index, check_credential, and all three marketplace tools (list_verified_human_tasks, purchase_verified_human_task, get_attestation_receipt). Then register_agent returns a key with Free plan: 1,000 seals/mo.Nine tools.
What each one does, and whether it needs your API key.
| Tool | What it does | Key? |
|---|---|---|
register_agent | Create a 5arz API key (Free plan: 1,000 seals/mo + 10 document checks). mode:"test" for an unlimited sandbox key. | No |
verify_human | Mint a signed PoHF credential — sessionId for work fulfillment, or memberId for personhood (optionally wallet-bound). | Yes |
check_credential | Independently verify a PoHF JWT against the public JWKS and read its claims. Pure crypto — no trust in 5arz. | No |
get_vhh_index | The Verified-Human-Hour index ($/hr) — a citable benchmark for verified human work. | No |
subscribe | Stripe checkout for a plan: Starter $99/mo, Growth $499/mo, Scale $2,499/mo. | Yes |
get_balance | Current plan, seals and document checks used this month, and what remains. | Yes |
| Verified-human-work marketplace — no API key, the payment is the authentication | ||
list_verified_human_tasks | Currently-buyable verified human work: USD price, price_usdc_atomic, slots remaining, settlement chains, and the receipt kind issued on completion. | No |
purchase_verified_human_task | Buy one slot. With only a task_id it returns the x402 HTTP 402 challenge (accepts[] + purchase_id). Settle the USDC, call again with x_payment and purchase_id to get an attestation_id. | No |
get_attestation_receipt | The Proof-of-Human-Fulfillment receipt for an attestation_id — signed packet, verifier identity, JWKS URL, and how to verify it yourself. | No |
Three calls to a checked seal.
register_agentYour API key (Free plan: 1,000 seals/mo).
verify_humanA signed PoHF credential (ES256 JWT).
check_credentialAnyone confirms it against the JWKS.
List the tools with curl.
The server speaks JSON-RPC 2.0. No key needed to list tools.
curl -s https://mcp.5arz.com \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'
Buy verified human work — no key.
The same server sells the work, not just the proof. An agent can complete a purchase end to end, with no API key and no person — the x402 payment is the authentication.
out_of_stock (HTTP 409 over REST).List
list_verified_human_tasks→ task id, USD price, slots left, settlement chains.Challenge
purchase_verified_human_task {task_id}→ HTTP 402 challenge:accepts[]+purchase_id.Settle
Settle the USDC on an offered chain, then call again with
x_payment+purchase_id.Receipt
get_attestation_receipt {attestation_id}→ the signed PoHF receipt + JWKS to verify it.
curl -s https://mcp.5arz.com \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/call",
"params":{"name":"purchase_verified_human_task",
"arguments":{"task_id":"wf_support_reply_001"}}}'
The 402 is the protocol working.
It comes back as an ordinary tool result carrying accepts[] (scheme, network, payTo, USDC asset, maxAmountRequired) and a purchase_id. Calling with no payment costs nothing.
The same loop over plain REST: GET /api/agent/tasks, GET /api/agent/tasks/{task_id}/buy, GET /api/attestations/{attestation_id}.
bind_human_to_payment — attaching a verified human to a payment that already settled on another rail — is a separate product and still lives only at https://api.5arz.com/mcp.
Works with the agent-payment rails.
Compatible with Verifiable Intent and the Visa Trusted Agent Protocol. The credential binds to payments on Agent Pay, Stripe, or x402/USDC.
5arz binds an agent to an ID-verified, live human — the claim Web Bot Auth, Know Your Agent and the Trusted Agent Protocol reference but don’t provide.
Start free.
Call register_agent in-session, or get your key in the browser. Free plan: 1,000 seals a month, no card.