Equation 1 · What Actually Happens Inside a Very Long Claude Context Window
What does this equation mean?
Read the formula alongside the article passage below. Each part has a deeper page with its role in the equation, the supporting passage and nearby citations.
the number of tokens. Read the equation part by part below; each part has a contextual explanation and a link to its mathematical background.
Read it piece by piece
How to interpret it
Read this expression with the definitions, units, and assumptions supplied by the article.
What the article says around this equation
Anthropic’s own engineering guidance, published in September 2025 as advice for developers building long-running agents, gives the clearest available first-party account of why context rot happens architecturally rather than treating it as an unexplained empirical curiosity [ 4 ] . The explanation rests on the transformer’s core mechanism: every token attends to every other token in the context through self-attention, so the number of pairwise relationships the model must represent grows with the square of the sequence length. For a context of n tokens, the compute spent by self-attention within a single layer scales as
Sources cited in the surrounding passage
These citations give research context. Read each source to check which claims it supports.
Return to What Actually Happens Inside a Very Long Claude Context Window