Codex enables 1M-context GPT-5.6 Sol for ChatGPT accounts

On August 17, 2026, OpenAI engineer Tibo Sottiaux announced that 1M-context GPT-5.6 Sol in Codex is now available to users with ChatGPT accounts, not just API keys; the default limit remains 272,000 input tokens.

Compiled by Sergey KostenchukPublished 2026-08-17Updated 2026-09-18

2026-08-17 Coding OpenAI

💻 Codex enables 1M-context GPT-5.6 Sol for ChatGPT accounts

On August 17, 2026, OpenAI engineer Tibo Sottiaux announced: the 1M context window for GPT-5.6 Sol in Codex is now enabled for ChatGPT accounts, not just API keys. The default remains 272,000 input tokens.

🌍 OpenAI has opened 1M-context GPT-5.6 Sol to regular Codex users: previously it only worked via API keys. For agentic coding, this means fewer losses during compaction of long sessions, but 1,050,000 tokens is a product claim, not a verified benchmark.

👤 The window can be expanded with three lines in ~/.codex/config.toml (model_context_window = 1000000, model_auto_compact_token_limit = 900000) or via -c flags for a single session. According to community reports, tokens beyond the default may be counted with an x2 multiplier — keep an eye on your usage.

Source 1: https://x.com/thsottiaux/status/2089143488696705077

Source 2: https://developers.openai.com/codex/config-reference

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