forgemeshlabs/x402-notary-mcp

*A ForgeMesh Labs product — the notary of the x402 agent economy.*
**Prove what your AI said, when it said it, and which model said it.**
Every AI output is just text. There's no proof a specific model produced a specific response at a specific time — and as agents start hiring other agents, that trust gap gets expensive. x402 Notary closes it: submit any inference, pay **$0.001** in USDC (automatic, via x402 on Base — no API key, no account), and get back a **signed, timestamped, chain-anchored receipt** that anyone can verify, free, forever.
> **We notarize the hash, not your secrets.** Your prompt and response are hashed and signed — never stored. Private signed receipts, publicly anchored by batch root.
Quick start (Claude Desktop / Claude Code / any MCP client)
WALLET_PRIVATE_KEY is a **dedicated low-balance Base wallet** for x402 micropayments — never your primary wallet. $1 of USDC notarizes 1,000 outputs.
**Requirements.** Node.js 20 or newer. The server only talks to https://notary.forgemesh.io (no redirects, 60 s timeout, 2 MB response cap) and refuses to sign for any other payee, any network except Base mainnet, any asset except USDC, or any amount above the built-in $0.01 per-call and $10 per-session caps. The environment variables X402_MAX_PRICE_USD and X402_SESSION_BUDGET_USD can only lower those caps, never raise them. Use a dedicated, low-balance wallet.
**Verification needs no wallet at all.** Skip the env block entirely and you can still verify receipts, inspect attestations, and read live stats.
Tools
| Tool | Cost | What it does |
|---|---|---|
| notarize_inference | $0.001 | Signed receipt for one {prompt, response, model_id} |
| notarize_batch | $0.005 | Up to 20 receipts in one call — built for audit trails |
| verify_attestation | **free** | Check any receipt: signature, content hash, Merkle proof |
| get_receipt | **free** | Fetch the public proof material for an attestation |
| notary_stats | **free** | Live volume, top models, anchored batches |
| notary_pubkey | **free** | The notary's Ed25519 key — verify receipts fully offline |
What a receipt proves
When you notarize an inference you get an attestation:
That's proof of three things:
1. **Existence** — this exact content existed at this exact time.
2. **Integrity** — change one character of the prompt or response and verification fails.
3. **Independence** — signatures verify offline with the published key; Merkle roots anchor batches. You don't have to trust the notary's word after the fact.
Verify anything, free, from anywhere
Any agent (or human, or CI job) can check a receipt before acting on the output behind it:
"valid": true means the content matches the notarized hash **and** the notary's Ed25519 signature checks out. Tampered content is rejected with the exact failing check.
When should an agent notarize?
Not every call — the outputs that matter:
- **Agent-to-agent handoffs** — prove what you passed downstream came from this model, unmodified
- **Paid deliverables** — research, reports, recommendations someone is paying for