Million-Token Context Windows

Million-token windows let you place entire codebases, document corpora, or multi-hour transcripts directly in context — no retrieval system required. The promise is in-context everything: the model reasons over the raw material rather than over a lossy summary.

• Whole-repository reasoning and refactors.
• Cross-document synthesis without chunking.
• Long-horizon conversations that retain early detail.

But capacity is not the same as effective use.

The advertised window is an upper bound, not a guarantee of uniform recall. Effective context — the span over which the model reliably retrieves and reasons — is usually smaller and uneven across positions.

Treat the window as a budget with non-uniform value: tokens near the edges are recalled better than tokens buried in the middle.