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How Claude learned to answer, and up to when

Claude goes through three training stages before any conversation, a broad reading of the world, an adjustment into a useful assistant, then self correction grounded in written principles, and the resulting knowledge stops at a date that varies by model.

Claude learns nothing while it answers you. All of its knowledge comes from training completed before it was made available, and this training unfolds over several clearly distinct stages, each adding a different layer to what the model can do.

Three stages before any conversation

The first stage consists of reading a considerable amount of varied text to acquire a general language capacity, before it even knows how to hold a useful conversation. A second stage, called post training, turns this foundation into an assistant capable of answering an actual request rather than simply continuing a text. A third stage teaches the model to critique and revise its own answers based on a set of written principles, a reference text that sets out what counts as a useful and careful answer, then a second pass reinforces the choice of the least problematic answers by relying on these same principles rather than on human judgements collected one by one. The figure below reproduces these three stages in the order they occur.

A cutoff date that varies by model

Once these stages are complete, Claude's knowledge is fixed, it knows nothing of what happened after a certain date, called the knowledge cutoff. This date is not the same for every model in the family, the figure gives a precise example for one of them. Asking a question about a recent event with no context provided is like asking someone to comment on a news story they have never read.

Providing a fresh source

The fix is applied message by message, pasting the text of a recent document directly into the conversation before asking the question.

Here is the article published today by our association, pasted below:
[text of the article]
Answer only from this text, without relying on what you knew before.

This anchoring sentence does not repair the knowledge cutoff, it works around it for the single question asked. The principle seen in the previous lesson, the position of a piece of information changes its weight, also applies to a fresh source, it benefits from being placed close to the question rather than buried in the middle of a long message.