Agent Embassy

npx add-mcp 'https://agent-embassy.fly.dev/mcp'

Agent Embassy

Agents pay for work and prove what happened.

Agent Embassy is an MCP server and x402 payment gateway for agent commerce: AI agents pay for machine-checkable work in USDC on Base (Coinbase x402 v2) and receive signed, portable Outcome Receipts as cryptographic proof of delivery. It also serves paid GPU compute market data (snapshot, history, alerts — $0.25 per call) for agents evaluating the compute market.

Live service: https://agent-embassy.fly.dev MCP endpoint: https://agent-embassy.fly.dev/mcp (Streamable HTTP) Agent skill: https://agent-embassy.fly.dev/skill.md

What it is

Most agent infrastructure stops at spending money — wallets, spending caps, policy engines. Agent Embassy sells the other half: server-side verification, executed for you, with the evidence embedded in a signed Outcome Receipt (embassy-receipt/1) that anyone can re-check independently. Proof of a specific delivery, not a score.

An agent calls a paid tool, pays $0.15–$1.00 in USDC through the open x402 payment protocol (HTTP 402 Payment Required, EIP-3009 authorization, settled on Base by the Coinbase CDP facilitator — the buyer needs no native gas), and gets back an Outcome Receipt (embassy-receipt/1): the full request → authorization → action → proof chain, signed with secp256k1 (EIP-191), fetchable and verifiable by anyone at /v1/receipts/:receiptId. Receipts are portable JSON — evidence, not a score.

Paid tools — x402, USDC on Base

Tool	Endpoint	Price	What you get
verified_check	POST /v1/check/verify	$0.15 USDC	Give us an HTTPS URL and conditions (status code, body substring, JSON path). We fetch it server-side once and return a signed Outcome Receipt with the check transcript and pass/fail verdict. Verdict passes only if every condition passes.
register_recovery	POST /v1/recovery/register	$1.00 USDC	Store a client-encrypted recovery blob with quorum rules. Queued for human review within 24 hours. Receipt commits to the stored blob hash.
compute_history	POST /v1/markets/compute/history	$0.25 USDC	Paid time series of GPU compute market prices: per-GPU cheapest/median/offer-count series or whole-market history, bounded and timestamped, embedded in your signed receipt.
compute_alerts	POST /v1/markets/compute/alerts	$0.25 USDC	Recent >10% per-GPU price moves scanned from the Embassy's market-intelligence log, most recent first, embedded in your signed receipt.
compute_spot_prices	GET /v1/markets/compute/spot	$0.25 USDC	GPU compute market snapshot: cheapest rentable ask per GPU class in USD/GPU-hour, observed live.

Payment flow: call the endpoint → receive 402 with the exact amount, payTo, chain (eip155:8453), and asset → resend with the X-PAYMENT header carrying your EIP-3009 authorization → the facilitator settles on-chain → you get your result plus the signed receipt. The receipt includes the settlement transaction, so payment and proof are bound together.

Free trust infrastructure

Never-ever-free doctrine: all market data and checks are paid. The only free surfaces are the proof mechanism itself:

Tool	Endpoint	What you get
verify_receipt	GET /v1/receipts/:receiptId	Fetch any Outcome Receipt as portable JSON and independently verify its signature against the public signer key at /.well-known/embassy-signer.json.
discovery	GET /skill.md, /llms.txt, /.well-known/*, POST /mcp (tools/list)	Machine-readable capability docs and manifests — no payment, no account.

Quick start for agents

Paid — GPU spot snapshot ($0.25 USDC):

GET https://agent-embassy.fly.dev/v1/markets/compute/spot?gpu=H100&max_results=5 returns 402 with the exact USDC amount — attach your X-PAYMENT (EIP-3009) authorization and retry.

Paid — verified URL check ($0.15 USDC on Base):

1. Discover exact pricing: GET https://agent-embassy.fly.dev/.well-known/x402.json
2. POST https://agent-embassy.fly.dev/v1/check/verify with { "url": "https://example.com", "expect_status": 200, "idempotency_key": "<uuid>" }
3. Without payment you get 402 with the exact amount, payTo, and chain. Attach your X-PAYMENT (EIP-3009) authorization and retry — the Coinbase CDP facilitator settles it, no gas needed on your side.
4. Response includes the signed Outcome Receipt. Verify it anytime: GET https://agent-embassy.fly.dev/v1/receipts/<receiptId>

MCP clients (Claude, Cursor, Cline, …): point at https://agent-embassy.fly.dev/mcp. tools/list is free; tools/call on paid tools follows the same x402 402 flow.

Outcome Receipts — portable proof of delivery

Every paid call returns an embassy-receipt/1 receipt:

• Five-stage chain: request → authorization → action → proof → liability_boundary — the exact boundary of what was promised and what was delivered.
• Tamper-evident: each receipt hash-chains to the previous one; signatures are secp256k1 / EIP-191.
• Publicly verifiable: anyone can fetch a receipt and check the signature against /.well-known/embassy-signer.json — no account, no API key.
• Bound to payment: the receipt carries the on-chain settlement transaction, so the money and the proof can't be separated.

This is the primitive agent commerce is missing: not a reputation score, not a review — evidence.

Machine surfaces

Built for agents first. Every surface is live and machine-readable:

Surface	URL
x402 manifest (prices, payTo, chains)	/.well-known/x402.json
MCP discovery	/.well-known/mcp.json
Universal discovery object	/.well-known/embassy.json
A2A agent card	/.well-known/agent-card.json
Agent skill file	/skill.md
Capability doc for LLMs	/llms.txt
OpenAPI	/openapi.json
Signer key (receipt verification)	/.well-known/embassy-signer.json
Health	/health

FAQ

What is x402? An open payment standard (pioneered by Coinbase) that uses HTTP 402 Payment Required for machine micropayments. Servers declare exact price, asset, chain, and recipient; clients attach a signed authorization; a facilitator settles on-chain. Agent Embassy implements x402 v2 with USDC on Base.

Do I need ETH for gas? No. The buyer signs an EIP-3009 USDC authorization; the Coinbase CDP facilitator submits the settlement transaction. You pay exactly the listed price in USDC.

Which chains? USDC settlement on Base (eip155:8453); the x402 manifest also declares Arbitrum One (eip155:42161).

How do I verify a receipt someone shows me? GET https://agent-embassy.fly.dev/v1/receipts/<receiptId> returns the full signed receipt JSON. Check the EIP-191 signature against the signer key at /.well-known/embassy-signer.json and confirm the settlement transaction on Base.

Is there a free tier? No. Never-ever-free: every check and every market-data call is paid ($0.15 verified checks, $1.00 recovery registration, $0.25 each for GPU spot snapshot, history, and alerts). Free surfaces are trust infrastructure only: receipt verification, discovery docs (/skill.md, /llms.txt, /.well-known/*), MCP tools/list, and the seller badge.

Who runs this? Agent Embassy is a live hosted service at https://agent-embassy.fly.dev, operated by notary.base.eth. Internals are intentionally black-box; the receipts are the trust surface, not the operator's word.

Registry listings

• Official MCP Registry: io.github.tacticalnoot/agent-embassy v1.0.0 (server.json)
• x402scan: listed, probe-detected paid resources
• 402index.io: listed, both services indexed healthy
• x402-list: submitted, pending human review

Contact

Dashadventure0@gmail.com

License

Source-available — see LICENSE. You can read everything here and build clients against the API, but you can't clone it into a competing hosted service or use the Agent Embassy / noot XLM name without permission.

Terms

Use of the service (including market data) is governed by TERMS.md: market observations are for end use — no scraping, mirroring, or reselling the data as a feed.