Expired50% confidenceFactExact time
The GPT 5.6 model natively supports a 1 million context window at the API level, but Codex has still not opened the full quota to subscription users.
1
Sources
50%
Confidence
Medium-term (~90 days)
Relevance
7/12/2026
First Seen
Valid until: 10/10/2026(expired)
Sources
GPT 5.6+Codex深度实测：三档模型与Ultra模式全解析
bilibilioil欧呦7/10/2026
Related Claims
UnverifiedThe API context length that GPT-5.5 is about to open supports up to 1 million tokens.81% similarUnverifiedCodex is based on GPT 5.5 and has a context window of approximately 400,000 tokens.80% similarVerifiedGPT 5.5 supports a one-million-token context window, capable of simultaneously processing approximately 500,000 to 700,000 words of code or documents.79% similar
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