Apple's On-Device Foundation Model Limited to 4K Context Window

talkaboutdesign · x · 2026-07-29

A developer building a native meeting summarization app using macOS 27's on-device intelligence highlighted a major bottleneck: Apple's on-device Foundation Model only has a 4K context window.

This limitation poses a significant challenge for productivity tools. A typical 30-minute meeting transcript requires roughly 5K–8K tokens, and a 60-minute meeting needs 10K–16K tokens. The restrictive context size makes it difficult for the local model to process and summarize standard-length meetings effectively.

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