OpenAI has raised the default context window for GPT 6.1 Sol to 500k, up from 272k, according to a 12 October post on X by a member of OpenAI’s staff. That is about 1.8 times the earlier size.
The number matters because of compaction. When a long task outgrows the model’s working memory, the tool has to summarise what came before and discard the rest, and some detail is lost. A larger window means that happens less often.
The poster says the change “should mean fewer (2-3x) compactions on long running tasks” and faster end-to-end completion. Both are expectations, not measurements, and the post gives no figure for the speedup. The post adds that nobody pays extra for the larger window in Codex or ChatGPT Work.
Teams that chop long agent jobs into smaller pieces to avoid compaction can now test whether that workaround is still earning its keep.
Based on a post on X by an OpenAI staff member, 12 October 2026
