SNAP — Shield Network Agent Payments

Private agent-to-agent payments on Solana using zero-knowledge proofs.

SNAP is live on Solana mainnet. See the security docs for the protocol's threat model and trust assumptions.

What SNAP Does

SNAP lets AI agents pay each other without on-chain observers learning who paid whom. Deposits enter a shielded pool under a cryptographic commitment. Withdrawals leave the pool with a Groth16 proof that shows the recipient is entitled to the funds without revealing which deposit is being claimed.

How It Works

1. Agent A deposits SOL plus a commitment into the pool.
2. Agent A sends a secret note to Agent B through a private channel.
3. Agent B reconstructs the Merkle path and generates a Groth16 proof.
4. Agent B withdraws SOL with withdraw_zk or withdraw_zk_relayed.
5. Observers can see the pool activity, but they cannot link the withdrawal to a specific deposit.

Quick Start

Install the SDK and its peer dependencies:

npm install snap-solana-sdk @solana/web3.js @coral-xyz/anchor

Minimal private payment:

import { Connection, Keypair, PublicKey, clusterApiUrl } from "@solana/web3.js";
import { SNAPClient } from "snap-solana-sdk";

async function main() {
  const connection = new Connection("https://your-rpc-url.com", "confirmed");
  const sender = Keypair.generate();
  const recipient = Keypair.generate();
  const pool = new PublicKey("B8SyffZKt8LABKogWjH9rZcjY5PV2hyYRCbTxxbcrpFf");

  const snapA = new SNAPClient(connection, sender);
  const snapB = new SNAPClient(connection, recipient);

  const note = await snapA.deposit(pool, 0.1);
  const serialized = SNAPClient.serializeNote(note);
  await snapB.withdraw(pool, SNAPClient.deserializeNote(serialized), recipient);
}

void main();

If you want a runnable walkthrough from this repo, use:

npx tsx examples/basic-payment.ts
npx tsx examples/agent-to-agent.ts
npx tsx examples/relayed-withdrawal.ts

Architecture

Component	Description
Solana Program	Anchor program with deposit, withdraw_zk, and withdraw_zk_relayed
ZK Circuit	circom Groth16 circuit using Poseidon and a depth-10 Merkle tree
SDK	snap-solana-sdk for note handling, proof generation, and client API
Agent Kit Plugin	Solana Agent Kit v2 plugin with snap_create_pool, snap_deposit, snap_withdraw, and snap_withdraw_private
LangChain Tools	snap-langchain-tools — StructuredTool wrappers for LangChain/LangGraph agents
Relayer	Express service for gas-abstracted private withdrawals

Mainnet

Pool denominations are 0.1 SOL, 1 USDC, and 10 USDC. See THREAT_MODEL.md for trust assumptions.

Field	Value
Program ID	9uePoqdgaXpqFLQM2ED1GGQrwSEiqe3r6tW1AfsnrrbS
Pool — 0.1 SOL	B8SyffZKt8LABKogWjH9rZcjY5PV2hyYRCbTxxbcrpFf
Pool — 1 USDC	5LeuHrPBgHNhgbCy996MEjcsBk5gNHhVj6AiuuCHZ8od
Pool — 10 USDC	ECuHf8kgiWfmL3Q6id4WGBQWvuukhzqvF5vsxuPAKZBv
Network	Solana mainnet-beta
Protocol fee	0.25%

Project Structure

├── programs/           # Solana program (Rust/Anchor)
├── circuits/           # circom ZK circuit
├── sdk-package/        # snap-solana-sdk npm package
├── agent-kit-tool/     # Solana Agent Kit plugin
├── relayer/            # Express relay service
├── agents/             # Demo agent scripts
├── examples/           # Minimal end-to-end examples
├── scripts/            # Deployment and quickstart scripts
├── docs/               # Troubleshooting, circuit, and compliance docs
└── tests/              # Integration tests

Development

# Build the Solana program
anchor build

# Run validator-backed tests
PATH="$HOME/.local/share/solana/install/active_release/bin:$PATH" anchor test --skip-build

# Build and test the SDK package
cd sdk-package && npm install && npm run build && npm test

Security

Known risks, protocol limits, and security documentation are in FINDINGS.md, docs/CIRCUIT_SPEC.md, docs/THREAT_MODEL.md, docs/COMPLIANCE.md, and docs/GOVERNANCE.md.

License

MIT