What variant of Codex are you using?
latest
What feature would you like to see?
I want to give feedback on the current GPT-5.5 context limit in Codex.
From the official announcement, I understand that GPT-5.5 in Codex is documented as having a 400K context window, while the API version supports 1M context. So this does not look like an undocumented bug.
My concern is with the product decision itself.
With GPT-5.4, Codex users could configure a much larger context window through model_context_window. For example:
model = "gpt-5.4"
model_context_window = 1000000
model_auto_compact_token_limit = 512000
That made GPT-5.4 very useful for large repositories and long-running coding sessions.
But with GPT-5.5, even though the model itself is supposed to be better at long-context reasoning and large coding tasks, Codex subscription users are now capped at 400K context. In practice, that makes GPT-5.5 feel like an upgrade in model quality but a downgrade in long-context usability inside Codex.
I understand that 1M context is expensive. I also understand why 400K might be a reasonable default for most users.
But I do not think it should be the hard limit for everyone.
For advanced Codex users, especially those working on large codebases, the choice between compaction and full context matters a lot. Codex compaction is good, but it is still a tradeoff. During complex debugging, architecture analysis, or multi-file refactors, I would often rather spend more quota and preserve more raw context than compact earlier.
A better approach might be:
- Keep 400K as the default for GPT-5.5 in Codex.
- Allow users to opt into larger windows, such as 512K, 768K, or 1M.
- Charge a higher usage multiplier when larger context is enabled, similar to how Fast mode already uses a higher cost multiplier.
The important point is user control. If a user prefers lower cost and faster compaction, 400K is fine. But if a user is willing to pay more quota for full-context runs, Codex should ideally allow that.
Right now, GPT-5.5 is advertised as stronger for long-context coding work, but Codex subscription users have less access to that long-context capability than they had with GPT-5.4. That feels like a regression in one of the areas where GPT-5.5 should matter most.
Please consider allowing advanced users to opt into 1M context for GPT-5.5 in Codex, even if it comes with a higher consumption rate.
Additional information
No response
What variant of Codex are you using?
latest
What feature would you like to see?
I want to give feedback on the current GPT-5.5 context limit in Codex.
From the official announcement, I understand that GPT-5.5 in Codex is documented as having a 400K context window, while the API version supports 1M context. So this does not look like an undocumented bug.
My concern is with the product decision itself.
With GPT-5.4, Codex users could configure a much larger context window through
model_context_window. For example:That made GPT-5.4 very useful for large repositories and long-running coding sessions.
But with GPT-5.5, even though the model itself is supposed to be better at long-context reasoning and large coding tasks, Codex subscription users are now capped at 400K context. In practice, that makes GPT-5.5 feel like an upgrade in model quality but a downgrade in long-context usability inside Codex.
I understand that 1M context is expensive. I also understand why 400K might be a reasonable default for most users.
But I do not think it should be the hard limit for everyone.
For advanced Codex users, especially those working on large codebases, the choice between compaction and full context matters a lot. Codex compaction is good, but it is still a tradeoff. During complex debugging, architecture analysis, or multi-file refactors, I would often rather spend more quota and preserve more raw context than compact earlier.
A better approach might be:
The important point is user control. If a user prefers lower cost and faster compaction, 400K is fine. But if a user is willing to pay more quota for full-context runs, Codex should ideally allow that.
Right now, GPT-5.5 is advertised as stronger for long-context coding work, but Codex subscription users have less access to that long-context capability than they had with GPT-5.4. That feels like a regression in one of the areas where GPT-5.5 should matter most.
Please consider allowing advanced users to opt into 1M context for GPT-5.5 in Codex, even if it comes with a higher consumption rate.
Additional information
No response