Add a fact-checker to Claude or ChatGPT
Give your chat AI a second pair of eyes: Gnomon as a custom connector, in a few minutes.
https://gnomon-api.deskwithnova.com/mcp/demo. No sign-in is needed. Then ask your AI to check a rewrite against your original, or to test a decision such as a hire or a price change before you act.What a connector is
A connector lets a chat AI use another service while it answers you. Connectors use an open standard called the Model Context Protocol (MCP). Once Gnomon is connected, your AI can hand it a rewrite or a decision, get a checked answer back, and tell you what it found.
Add Gnomon in the Claude or ChatGPT app
- Open your app’s connector settings and choose to add a custom connector. The exact menu names change from time to time, and custom connectors may depend on your plan, so check your app’s help pages if you can’t see the option.
- Name it Gnomon and paste
https://gnomon-api.deskwithnova.com/mcp/demoas the address. - Leave sign-in empty. The demo address needs none and allows 20 calls a minute.
- Turn the connector on in a new chat and try one of the prompts below.
Things to ask
- “Rewrite this quote email to sound friendlier, then use Gnomon to check you didn’t change any prices, dates or conditions.”
- “Use Gnomon to check whether I can afford to hire a full-time barista. Here are my monthly numbers.”
- “Use Gnomon to compare raising prices by 5% or 10%, and find the lowest safe rise.”
- “Check this answer against these sources with Gnomon and list anything the sources don’t support.”
Behind the scenes your AI picks from Gnomon’s tools, including check_text and repair_text for rewrites, check_decision, simulate and find_best_plan for decisions, and run_model for ready-made business models such as hiring, cash flow, price changes, job quotes, stock orders and loans.
For developers
Make a key in the Gnomon console: sign in with a NOVA account, create a free test key (100 checks a day) or add NZ dollar credit for a live key. Then connect from Claude Code, the Claude API, or the OpenAI and xAI Responses APIs using the full address https://gnomon-api.deskwithnova.com/mcp and your key. The API docs have the exact commands and examples.
Why add a checker at all?
Chat AI sounds sure even when it is wrong, and a rewrite can quietly change a fact. A checker that doesn’t guess catches those before they reach a customer. Read what tends to change in AI rewrites and how often AI is wrong.
Questions
How do I add a custom connector to Claude or ChatGPT?
Open the app’s connector settings, choose to add a custom connector, give it a name and paste the connector’s address. Availability can depend on your plan, so check the app’s help pages if the option is missing.
What is Gnomon’s connector address?
For the Claude and ChatGPT apps, use https://gnomon-api.deskwithnova.com/mcp/demo with no sign-in. It allows 20 calls a minute.
Does the Gnomon connector cost anything?
The demo connector needs no sign-in. Developers using the API get free test keys with 100 checks a day, and live keys use prepaid credit in NZ dollars.
What is MCP?
The Model Context Protocol is an open standard that lets AI apps connect to outside tools and data, such as Gnomon.
Give your AI a second pair of eyes.
Connect the demo in minutes, or make a free test key for your own app.