Expired80% confidenceFactTime unknown
Codex is based on GPT 5.5 and has a context window of approximately 400,000 tokens.
1
Sources
80%
Confidence
Medium-term (~90 days)
Relevance
5/31/2026
First Seen
Valid until: 8/29/2026(expired)
Sources
Related Entities
Related Claims
VerifiedThe Codex desktop client supports selecting the GPT-5.5 model.80% similarUnverifiedThe 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.80% similarUnverifiedReports indicate that the context window for GPT-5.6 in Codex may be 372,000 tokens, which has not yet been officially confirmed by OpenAI.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.77% similarUnverifiedIn Codex, a 1 million token context window can be unlocked for GPT-5.6 Sol by adding the model slug and manually setting the context window to 1 million and the auto-compact threshold to 900,000.76% similar
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