Claude Opus 5.5: specs, API pricing and data

How much text the model keeps in view in a single request, question and answer included. It matters for long documents and whole code projects. A token is a fragment of a word.

The longest answer it can write in one go: useful for reports, long code or translations of whole documents.

What it costs to have the model read a million tokens (your question, the documents, the code). It is the official list price, before discounts.

The reduced price when part of the request is identical to one sent recently, for example the same instructions or the same document: the vendor keeps it in memory and charges less for it.

What a million tokens written by the model cost. It usually costs more than the input and is the figure to watch when answers are long.

The month up to which the model's knowledge reaches. For more recent facts it needs web search or your documents.

The model can take images (photos, screenshots, charts) as well as text.

The model can call functions and tools (search, calculations, other applications) to take actions and not only write text: it matters for assistants and agents.