veristat

x402-paid multi-model verification MCP server on Cloudflare Workers.

Status: public work in progress. The service runs on the Base Sepolia testnet only. Mainnet, registry publication and outreach are not launched. veristat is a working name; a rename is planned before any public product launch (docs/decisions/0005-select-mathesa-masterbrand.md). See About this repository.

An agent submits a claim, plan, or draft; veristat fans it to a heterogeneous panel of frontier models (Anthropic + OpenAI + Google — never two from the same vendor), synthesizes a structured verdict (consensus, agreements, contradictions, dissent), and returns it. Payment per call via x402 (USDC on Base). The payment is the credential — buyers need no vendor accounts.

Docs

docs/SPEC.md (decided build spec) · docs/STRATEGY.md (why + kill condition) · docs/ROADMAP.md (launch phases + status) · docs/TESTING.md (test pyramid, wallet runbook) · docs/RUNBOOK.md (ops, incl. CI/CD) · docs/ARCHITECTURE.md (Cloudflare architecture + payment-flow diagrams) · docs/EVALS.md (quality baseline and live-run boundary) · docs/plans/prelaunch-unblocked-backlog.md (unblocked follow-on work) · docs/context/current-state.md (compact current-session handoff).

Current deployment

As of 2026-09-04, veristat is deployed for a Base Sepolia rehearsal:

• MCP endpoint: https://veristat.grant-23a.workers.dev/mcp
• Network: eip155:84532
• Facilitator: https://api.cdp.coinbase.com/platform/v2/x402
• D1 database: veristat (63379492-64ce-48a0-b39a-82aa54726dae)
• Testnet receiver: 0x86CdAe1A22458442BaB9E10216a7E96b606d3635
• Active Worker version: 26d30f8c-4241-4e92-8cbc-52416fd1a003 (deployed 2026-09-04)

Three discovery-bearing testnet payments have settled. The final controlled diagnostic returned {"bazaar":{"status":"processing"}} on both verify and settle, but the resource remained absent from merchant lookup, semantic search, and the full Bazaar catalog through +60 minutes. Sanitized evidence is attached to x402-foundation/x402#2112. That remains the Phase 2 blocker unless the operator explicitly records the narrow listing waiver in docs/ROADMAP.md.

Tools

Tool	Price	Status
consensus_check	$0.50 for the current fulfilled 3-panel check + $0.50 large-input surcharge; exact price quoted in the 402	live (panel_size: 5 is accepted for compatibility but fulfilled and quoted as 3-panel)
get_sample_verdict	free	live
research_fanout / get_research_result	$12–25 dynamic	stub — returns NOT_AVAILABLE

Architecture

• MCP: agents SDK McpAgent, streamable HTTP at /mcp.
• Payments: x402 v2 exact scheme via @x402/core, MCP-transport handshake (_meta["x402/error"] / _meta["x402/payment"]) compatible with withX402Client from agents/x402. Dynamic per-request quoting with signed, 5-minute quote tokens (src/payments/quoting.ts). Settlement happens only after the tool succeeds — a failed panel never charges the buyer.
• Facilitator: abstracted behind @x402/core's FacilitatorClient interface (src/payments/x402.ts). The deployed Base Sepolia rehearsal and planned mainnet launch use Coinbase CDP; x402.org remains available for plain testnet payment testing, and Cloudflare's Monetization Gateway is a later constructor-level swap. Tests inject test/mock_facilitator.ts.
• Panel: parallel fan-out, 60s ceiling, degrades gracefully at 2/3 with panel_degraded: true + refund note (automatic refunds remain post-launch).
• Synthesis: one schema-enforced model call; prompts versioned in src/prompts/, version logged per request.
• Data handling and logging: each submission is sent to Anthropic, OpenAI, and Google for the panel; the content and panel outputs are then sent to Anthropic for synthesis. Under ADR-0004 (zero-toxic-waste), D1 does not store submitted text, raw panel outputs or verdict bodies. requests holds a SHA-256 input hash, verdict label, consensus score, token count, model count, latency and prompt versions. settlements stores transaction hash, payer wallet and amount, joinable to requests by request_id. See docs/decisions/0004-privacy-retention-policy.md and docs/plans/privacy-and-retention.md.

Deployment configuration

What	Where	How
USDC receiving wallet	PAY_TO_ADDRESS in wrangler.jsonc	configured to the throwaway testnet receiver above; USER must supply a real Base mainnet address before cutover
Public endpoint URL	PUBLIC_URL in wrangler.jsonc	configured to https://veristat.grant-23a.workers.dev/mcp — the URL the Bazaar must catalog
CDP API keys	CDP_API_KEY_ID / CDP_API_KEY_SECRET Worker secrets	configured for the rehearsal; provision separately for a new environment and never commit their values
Panel API keys	ANTHROPIC_API_KEY, OPENAI_API_KEY, GOOGLE_API_KEY	local: .dev.vars (copy .dev.vars.example); prod: npx wrangler secret put <NAME>
Quote signing secret	QUOTE_SIGNING_KEY	openssl rand -hex 32, same channels as above
D1 database id	database_id in wrangler.jsonc	configured to the live veristat database shown above
Buyer test wallet	BUYER_PRIVATE_KEY env for scripts/paid-call.mjs	any wallet with base-sepolia USDC from https://faucet.circle.com — must not be the deployer's
Registry metadata	server.json	finalized as io.github.originallgb/veristat, version 1.0.0, using the public endpoint above

Run it

npm install
npm test                                  # 402→verify→settle cycle + negative paths vs mock facilitator
cp .dev.vars.example .dev.vars            # then fill in real keys
npx wrangler d1 migrations apply veristat --local
npm run dev                               # http://localhost:8787 (/mcp, /health, /price)
node scripts/smoke.mjs                    # free tool + unpaid 402 challenge (no keys needed)
E2E_UNPAID_ONLY=1 node scripts/e2e.mjs    # full unpaid matrix, exits nonzero on failure
node scripts/make-test-wallet.mjs         # buyer key → .wallets/, prints Circle faucet link
# after securely exporting BUYER_PRIVATE_KEY from the generated file:
ENABLE_PAID_CALL=1 NETWORK=eip155:84532 node scripts/e2e.mjs  # approved $0.50 paid e2e

Full testing strategy (wallet roles, negative-path matrix, Bazaar listing verification): docs/TESTING.md. Ops: docs/RUNBOOK.md (node scripts/dashboard.mjs is the dashboard, node scripts/check-bazaar.mjs answers "are we actually listed").

Deploy (testnet first)

npx wrangler d1 migrations apply veristat --remote
npx wrangler secret put ANTHROPIC_API_KEY # …and OPENAI_API_KEY, GOOGLE_API_KEY, QUOTE_SIGNING_KEY
npx wrangler deploy
EXPECTED_VERSION=<version-id-from-deploy> \
  VERISTAT_URL=https://veristat.grant-23a.workers.dev/mcp \
  node scripts/smoke.mjs

Cloudflare version metadata is active in /health. The smoke command must report the same version ID that wrangler deploy created; the current verified value is the active Worker version shown above.

scripts/smoke.mjs defaults to localhost:8787. A stale wrangler dev --remote process there can make a production check appear to fail or validate the wrong code. For deployment verification, always set the explicit public VERISTAT_URL; inspect the listener with lsof -nP -iTCP:8787 -sTCP:LISTEN before using localhost.

Mainnet checklist (spec §8): upgrade to Workers Paid ($5/mo) before the first mainnet call (free-plan 10ms CPU cap can kill a request after settlement); set NETWORK=eip155:8453; point FACILITATOR_URL at the Coinbase CDP facilitator; real PAY_TO_ADDRESS; list in the Coinbase x402 Bazaar and the official MCP registry (server.json).

Dashboard

There is no dashboard. The logs are the dashboard:

npx wrangler d1 execute veristat --remote --command \
  "SELECT created_at, tool, amount_usd, tx_hash, payer FROM settlements ORDER BY id DESC LIMIT 20"
npx wrangler d1 execute veristat --remote --command \
  "SELECT count(*) requests, sum(degraded) degraded FROM requests"

Bazaar listing metadata

• Name: veristat
• Category: verification / evaluation
• One-liner: An independent second opinion a model cannot give itself, in one paid call with zero account setup.
• Endpoint: https://veristat.grant-23a.workers.dev/mcp (x402, USDC on Base, exact scheme)
• Discovery: free get_sample_verdict tool returns a real verdict, methodology, and price card.

About this repository

This is a learning-in-public work in progress, published as-is.

• History. The commit history was rewritten before publication to remove local machine paths, agent session logs and tool attribution trailers. No credentials were ever committed; the full history was scanned with gitleaks.
• Issue numbers. References such as #14 in docs/ point to the private development tracker and do not resolve in this repository.
• Agent-oriented docs. AGENTS.md, CLAUDE.md and much of docs/ are written for the coding agents that help build this. "Operator" means the maintainer.
• Security. See SECURITY.md. Please report vulnerabilities privately.
• Licence. Split by audience (ADR-0007):
  • The service (everything outside examples/) is under the Functional Source License 1.1, MIT Future License (FSL-1.1-MIT). You may use, modify and redistribute it for any purpose except a competing commercial product or service. Each version becomes MIT two years after it is published.
  • The buyer example in examples/node-buyer/ is MIT. Copy it into your own agent freely.