What is a Knowledge Cutoff?
The knowledge cutoff, told as a story about the day the parrot school closed its books — after which the parrot knows nothing.
Asked who won this year, the parrot confidently names last year's team.It is not wrong so much as old. To the parrot, that is the most recent news there is. Why?
One day the school closes the books. Nothing printed after that day was ever read.The school of reading takes months. So one day the books are closed and school ends — every shelf after that is blank to the parrot.
The knowledge cutoff is the day the parrot closed its books. It knows nothing after.Every parrot has its own closing day. Ask about something after it and, with luck, it says so — or it continues plausibly, which is worse. Fresh news comes from the librarian or a tool.
The blank after that day is filled by the librarian and tools, not by school.When the librarian finds fresh news and puts it on the tray, the parrot answers from that. A search tool does the same. Far cheaper than sending it back to school.
Being before the day does not mean it knows. Rare things in the books stay unknown.Even before the day, something that appeared in one line of one book is hazy — and it can still be continued plausibly. So the librarian and tools are not just for recent news.
Knowledge cutoff = the day the parrot closed its books. It knows nothing after — yet may continue instead of saying so. Each parrot has its own day, so ask until when first, and let the librarian or a tool put fresh news on the tray. Even before the day, rare things in the books stay unknown.
The last point in time covered by a model's pre-training data. Events, prices, versions and law changes after it are not in the parameters, so asking may yield stale answers or hallucinations. Each model version has its own cutoff; recency is patched with RAG (injecting retrieved evidence) or a search tool call. Even facts before the cutoff can be unreliable if they were rare in the training data.
When grown-ups say it
- Knowledge cutoff
- The day it closed the books. Nothing after that day is in the parrot's head.
- Training data date
- The date on the last book on the shelf. Can sit a bit before the closing day — the last few months are thin on the shelf.
- Search tool
- The search box the parrot can use. Fresh news gets searched and put on the tray. → the toolbox
- RAG
- The page the librarian found. The librarian searches first, every time. → the page the librarian found
- Recency
- How fresh its news is. Doubt anything that changes often: winners, prices, laws, versions.
- Model version
- The number on the parrot's name tag. Newer versions closed their books later. Check which parrot you have.
- Hallucination
- Continuing without knowing. Ask about after the day and this is what comes out. → the plausible parrot
- Pre-training
- The school of reading. Closing the books is the day school ends. → the school of reading