Anyone who has used AI programming assistants or long-text processing tools has encountered that frustrating moment—when the model suddenly "forgets". It starts repeating code it already wrote, forgets key requirements mentioned three minutes ago, or gradually drifts off-topic in long conversations. This isn't the model's fault; it's the physical limitation of the context window.
Even the most advanced models with a 128K context window fall short for complex multi-step tasks. When the window is full, the model is forced to compress its history, silently discarding those "unimportant" details—details that often determine the success or failure of the task. Larger windows only delay the problem; stuffed million-level windows also lose information in the middle sections.