For ChatGPT and Claude

The Stoic quote checker, inside your AI assistant

Ask an AI assistant whether Marcus Aurelius really said something and it will often repeat the same misattributions that circulate everywhere else. This connector gives the assistant something better than its memory: the library behind our quote checker, 163 cited passages and 26 documented misattributions, so it can tell you where a quote actually comes from.

It is free, read-only, and needs no account.

Connect it to Claude

In Claude, open Settings, then Connectors.
Choose Add custom connector, name it Marcus, and paste this URL:
```
https://getmarcus.app/api/mcp?client=claude
```
Leave authentication empty, add it, and make sure it is switched on in a conversation.

Connect it to ChatGPT

In ChatGPT settings, under Apps & Connectors, turn on Developer mode in the advanced settings.
Create a new app with this URL and no authentication:
```
https://getmarcus.app/api/mcp?client=chatgpt
```
Select it from the tools menu in a conversation, or mention it by name.

Once the listing is approved in each directory, you will also be able to add it from there without the URL.

What it does

check_quote takes a quotation, with or without its attribution, and returns one of four answers:

Misattributed. It is on our published list. You get who actually wrote it and a link to the full source trail.
Verified. It is in the library, with the work and section, so you can open the book and check. If it is real but credited to the wrong person, it says so.
Close. It resembles something we hold. Usually that is a different translation, or a paraphrase that has hardened into a quotation, and you get the real passage to quote instead.
Not in the library. See below. This is not the same as fake.

find_quotes takes a topic in plain words, such as grief, anxiety about the future, or a difficult coworker, and returns genuine passages on it, each verbatim from a named translation with its work and section. It can be limited to one author.

Things to ask

Did Marcus Aurelius really say "What we do in life echoes in eternity"?
Is "the obstacle is the way" a real quote?
Who actually said "Be kind, for everyone you meet is fighting a hard battle"?
Give me a real Seneca quote about grief, with the source.
I want a Stoic quote about dealing with difficult people for a talk. Make sure it is genuine.

What it cannot tell you

The library is 163 passages, not the whole of ancient philosophy. When a quote is not in it, the honest answer is that we cannot find it, which describes our search, not the quote. Two common reasons a real passage comes back that way: we do not hold it, or you have a different translation. Two honest translations of the same Greek can share almost no words.

What a not-found answer does tell you is that nobody has supplied a book and a chapter. Until someone can, treat the attribution as unchecked.

Privacy

The assistant sends only the quote or topic it is asking about. There is no account, we do not store or log what you check, and the checker makes no calls to any AI service. The privacy policy has the details.

Support

Found a wrong answer, or a misattribution we should add? Write to hello@getmarcus.app. Corrections are published, not quietly made.

The same checked library is what Marcus reads from: a daily Stoic practice for iOS, with a morning preparation, a daily reading, and an evening examination.

Explore the app →