# Add FactStamp to an agent

FactStamp is a remote MCP server. One URL, no account, no API key:

    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 https://factstamp.agentrails.workers.dev/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.
  One-click (no plan, no listing): https://claude.ai/customize/connectors?modal=add-custom-connector&connectorName=FactStamp&connectorUrl=https%3A%2F%2Ffactstamp.agentrails.workers.dev%2Fmcp
- **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 add-connector dialog (checked across all five
vendors' documentation on 6 October 2026). The other four are a manual paste, by the vendor's design:
open the dialog above, paste the URL, save. Nothing is lost by that, and no tunnel or local
server is needed, because our server is public HTTPS speaking Streamable HTTP.

The directory routes (Claude's Connectors Directory, OpenAI's public plugin directory shared by
ChatGPT and Codex, the others) are a separate thing that needs an account and a review queue. The one-click link above does not:
it opens the same dialog by hand, and the connector then behaves identically, because both run
on the same MCP runtime. What a directory listing adds is discovery, not capability: browse,
search, and being suggested inside a chat.

## Try it before paying

These two tools cost nothing, on any rail, with no account:

- `list_series`
- `route_claim`

Ask the agent: *use list_series to list what FactStamp covers*, then have it check one
figure from the list. A paid door is only reached when the agent asks for a verdict.

## Paid doors

| Tool | Per call |
|---|---|
| `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 is US$0.50 for 30 days of daily re-checks, a
portfolio of up to 25 references is US$5, a document is US$0.25 for up to 5 claims.
The full list, with the free surfaces, is at https://factstamp.agentrails.workers.dev/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: https://factstamp.agentrails.workers.dev/llms.txt, https://factstamp.agentrails.workers.dev/SKILL.md,
  https://factstamp.agentrails.workers.dev/.well-known/mcp.json, https://factstamp.agentrails.workers.dev/.well-known/mcp/server-card.json,
  https://factstamp.agentrails.workers.dev/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.
- Support: info@alpineai.com.au.

Version 0.1.0. Last updated 6 October 2026.