Veritap

An MCP endpoint where agents check whether a real-world fact can be verified — before acting on it.

Live: https://veritap.dev/mcp · npm: veritap-mcp · MCP registry: dev.veritap/veritap

{ "mcpServers": { "veritap": { "command": "npx", "args": ["-y", "veritap-mcp"] } } }

Free, no auth, read-only, and it never returns a bare failure. Covers businesses, listings, objects and places. Claims about individuals are refused as a matter of policy.

What works today

• Business-exists claims are answered on the spot -- an automated desk check across GLEIF LEI records, SEC EDGAR filings, Wikidata, and website liveness returns a dated evidence bundle with sources and an honest confidence. Free while verification is new. Never a bare verdict.

• Triage (triage_unknowns): batch every uncertainty in a task; each is classified as answerable-yourself (with a suggested source), verifiable here, or not determinable (with planning advice). Items you can settle yourself are routed away, not sold to you.

• Plan mapping (plan_verification): which steps of a multi-step plan rest on checkable real-world facts.

• Feasibility checks (check_feasibility and friends): call speculatively before relying on, buying from, or citing anything seen online.

Answers repeat instantly from a shared attestation cache. Nothing is charged; paid verification is not open.

Related MCP server: Lenz MCP Server

What this actually is

A demand sensor. The product is the ledger, not the verification.

Agents constantly hit steps that depend on facts they cannot confirm, and today they either guess or silently drop the step — so the demand is invisible. Every call here writes a structured row: what was asked, what it was worth to the caller, and whether anything could answer it. Requests we cannot fulfil are the most valuable rows in the database.

That dataset cannot be backfilled, which is why the endpoint went live before fulfillment existed.

Design decisions worth knowing

• No human in the loop, ever. No dispatch, no verifier network. If the copy ever implies otherwise, scripts/a3-audit.mjs fails the build.

• No outbound referrals. A miss keeps its signal in-house, so it must stay decision-grade on its own: closest alternatives, honest self-help, and a real promise to report back (src/notify.ts).

• Quarantine, don't drop. Suspected flooding tags rows rather than refusing them. A wrongly-throttled agent prunes us from its tool rotation permanently; a wrongly-tagged row costs nothing and can be un-flagged later.

• Claims about people are refused, not deferred. FCRA exposure and the obvious harassment vector. Refusals are logged without their text. scripts/policy-check.ts is a two-sided control battery — a gate that refuses nothing and a gate that is switched off look identical from the outside.

• The fingerprint is not an identity. MCP has no installation id, so components are stored separately rather than baking a guess into a hash.

Layout

src/index.ts     Worker entry, MCP protocol layer, cron
src/router.ts    the core: normalize -> hash -> cache -> catalog -> ledger
src/policy.ts    people-claim exclusion (hard refusal)
src/triage.ts    unknown classification, routes web-answerable items away
src/notify.ts    the return path: report back when a gap closes
src/ledger.ts    append-only demand ledger, batched writes
src/admin.ts     operator dashboard, Cloudflare Access protected
public/          agent-legible surface: llms.txt, openapi, well-known, pages
docs/decisions.md  every deviation from spec, with reasoning

Develop

npm install
npx wrangler d1 migrations apply groundtruth --local
npx wrangler dev

Gates that must pass before any deploy:

npx tsc --noEmit
node scripts/a3-audit.mjs      # honesty: no dispatch, no referral, no purchasability
node scripts/policy-check.ts   # people-claim gate, both directions
./scripts/history-scan.sh      # secrets across git HISTORY, before any public push

history-scan.sh exists because a working-tree audit cannot catch what a public push actually exposes. Grepping git ls-files only ever sees the current checkout — it passes happily while earlier commits, and commit messages, still carry the thing you removed.

Secrets are never committed. ALERT_EMAIL and NTFY_TOPIC are set with wrangler secret put — the ntfy topic in particular is a capability, since anyone holding it can both read the digest and publish alerts to the operator.

Stack

Cloudflare Workers (stateless createMcpHandler — no Durable Objects), D1, @modelcontextprotocol/server v2. A frozen project costs $0 to leave running, which is the point: the sensor keeps accruing whether or not anyone is watching.

MIT