Architecture

One engine, two doors, one ledger.

One engine, two doors, one ledger. Brass is money moving; ink is data moving; dotted is verify / settle.

scroll the diagram sideways ↔

Assay architecture: paying agent → Assay (REST + MCP over one engine) → The Graph; Blocky402 verify/settle → HCS receipts; the receipt written to the ERC-8004 Reputation Registry on Base Sepolia with the file on IPFS

Read path

  1. Agent asks; the route answers 402 with x402 requirements on hedera:testnet, priced by the work the route does.
  2. Agent signs, retries. Blocky402 verifies; the handler runs; settlement happens only on success.
  3. The engine reads the Agent0 subgraph with _meta. No pinned deployment and block, no answer.
  4. Eleven detectors → verdict, evidence, and what would change it. Confidence only from payment-backed independent reviews.
  5. A receipt lands on the HCS topic. The topic, read via the mirror node, is the whole memory. No database.

Write path — the receipt

After paying, the agent writes ERC-8004 feedback about Assay on Base Sepolia whose file carries proofOfPayment with the Hedera settlement. The file is pinned to The Graph's IPFS node because the indexer reads feedback only through file/ipfs. The next read of Assay shows a review that cost what the work cost.

Prose and the Mermaid source: docs/ARCHITECTURE.md · file: /architecture.svg