Synthesis
A runnable demo of two agents completing a payment with policy checks, trust scoring, and an on chain anchored audit trail, all verifiable over HTTP.
What it is
Synthesis is an end to end demo of two agents (a buyer and a seller) running a payment flow with a cryptographic check at every gate. It ties together three of the trust projects: Sardis for payment and policy, FIDES for identity and trust, and agit for the audit trail.
The problem it solves
It answers the question the manifesto keeps coming back to: can agents be trusted with money. The demo shows that the answer is yes, if every transaction passes policy, the counterparty has enough trust, and the whole flow is signed and anchored so anyone can verify it.
How it works
The buyer creates an Ed25519 identity, discovers the seller through FIDES, and checks its trust score via a graph traversal with decay. It runs the amount through the real Sardis policy engine (per transaction and lifetime caps, token and destination rules), and only then pays. Every step is recorded in agit as a signed, hash chained commit, a keccak256 Merkle root is computed over the commits and anchored to Base Sepolia, and twelve public endpoints let anyone re verify the signatures and the Merkle proof. Three scenarios show the happy path, a block on low trust, and a rejection on a policy violation.
Where it fits
It is the reference that shows the trust stack working together: agents that pay (policy), agents that trust (identity and graph), agents that cooperate (signed commits), and agents that keep secrets (encrypted audit). Built for the Synthesis hackathon (Ethereum and AI agents).
Status
Working in simulation mode with no external keys required, forty eight passing tests, and contracts deployed on Base Sepolia. Live FIDES services and encryption are optional and degrade gracefully when absent.