Add FactStamp to an agent
FactStamp is a remote MCP server. One URL, no account, no API key. Any assistant that accepts a custom remote server can use it today.
https://factstamp.agentrails.workers.dev/mcp
Transport: Streamable HTTP. Prices are per call, in USDC on Base over x402, or from a prepaid pack bought by card at /packs.
Add it, per assistant
- Claude — Customize → Connectors → Add → Custom → Web. Free, Pro, Max, Team and Enterprise plans. The one-click link below opens Claude's add-connector dialog with FactStamp already filled in, on any plan. A custom connector then works on Claude, Cowork and Claude Desktop. Add FactStamp to Claude
- ChatGPT — Settings → Apps & Connectors → Advanced: turn on developer mode, then Create. Any account that can turn developer mode on (workspace admins on business plans). Paste the server URL as an MCP connection. OpenAI renamed connectors to apps, so older guides say Settings → Connectors; the toggle is the same one.
- Perplexity — Account settings → Connectors → + Custom connector → Remote. Paid tiers (Pro, Max, Enterprise). Streamable HTTP only. The legacy SSE transport is not supported.
- Grok — grok.com/connectors → New Connector → Custom. Any signed-in account. Grok discovers whatever tools the server exposes. Our server is public HTTPS over Streamable HTTP, so no tunnel service is needed, which the docs otherwise ask for.
- Meta Muse — Ask Muse to create a Custom Connector. Any signed-in account. Meta states it does not review custom connectors.
Click-paths read off each vendor's own documentation on 6 October 2026. All five accept a user-added server with no directory listing and no vendor review. We are not listed in any vendor's directory, and this page does not claim we are. Only Claude publishes a link that prefills its own dialog; the other four are a manual paste, and no tunnel or local server is needed because ours is public HTTPS over Streamable HTTP. The directory routes (Claude's Connectors Directory, OpenAI's public plugin directory, the others) need an account and a review queue; the one-click link above does not, and the connector behaves identically either way, because both run on the same MCP runtime. What a listing adds is discovery, not capability.
Try it before paying
list_series and route_claim cost nothing, on any rail, with no account. Ask the agent to list what
FactStamp covers, then have it check one figure from that list. A paid door is only reached when
the agent asks for a verdict.
Paid doors
check_entity | US$0.05 |
check_figure | US$0.05 |
verify_citation | US$0.02 |
verify_package | US$0.02 |
check_document | US$0.25 |
watch_add | US$0.50 |
watch_portfolio | US$5 |
verify_bulk | US$0.12 |
Standing work is priced per unit: a watch US$0.50 for 30 days of daily re-checks, a portfolio of up to 25 references US$5, a document US$0.25 for up to 5 claims. The full list is at /pricing.md.
What a call returns
A verdict from a named publisher's own dated series or from the open registers, cited, plus
an Ed25519-signed receipt that verifies offline. No model sits in the verdict path: the same
question against the same registry and snapshot reproduces the same answer, and
unknown is a first-class answer rather than a failure.
If you are an agent reading this
- Machine-readable: /llms.txt, /SKILL.md, /.well-known/mcp.json, /.well-known/mcp/server-card.json, /openapi.json.
- An unpaid call returns the x402 challenge (HTTP 402) naming the price and the asset, so you can see the cost before anything settles.
- A plain-text copy of this page: /connect.md.
Version 0.1.0. Last updated 6 October 2026. Support: info@alpineai.com.au