GPT-5.6 Sol Max can exhaust the entire 5-hour Plus quota after one ~15k+ character prompt

What version of Codex CLI is running?

0.150.1

What subscription do you have?

ChatGPT Plus

Which model were you using?

GPT-5.6 Sol, reasoning max

What issue are you seeing?

A single long, structured Codex prompt of roughly 15k+ characters can consume the entire 5-hour Plus usage window in one turn.

This has happened during normal repository work where the prompt is detailed because it contains safety constraints, branch/worktree checks, implementation scope, regression requirements, and verification steps. The prompt itself is long, but it is still one bounded engineering task.

Observed pattern:

1. 5-hour quota resets and is available.
2. Start a fresh Codex turn using GPT-5.6 Sol with Max reasoning.
3. Submit one structured prompt above roughly 15k characters.
4. Codex performs the task or begins working on it.
5. The 5-hour usage allowance is exhausted after that single turn, even while substantial weekly allowance remains.
6. Further work must wait for the 5-hour reset, forcing the same task to be reconstructed/resumed later.

The practical effect is that one detailed prompt can make Codex unavailable for the remainder of the rolling window. This is especially disruptive for complex but controlled engineering workflows where long prompts are used to reduce ambiguity and prevent unsafe repository actions.

I have observed this more than once. The issue appears strongly correlated with long prompt/context size on GPT-5.6 Sol Max rather than simply wall-clock duration.

I am intentionally not posting private repository names, session IDs, or conversation contents publicly. I can provide private diagnostic/session information to OpenAI if requested.

What steps can reproduce the bug?

1. Use Codex CLI 0.150.1 on a ChatGPT Plus account.
2. Select GPT-5.6 Sol with Max reasoning.
3. Start with a fresh 5-hour allowance.
4. Submit a single detailed engineering prompt of around 15k+ characters containing repository checks, scope constraints, implementation requirements, tests, and final reporting instructions.
5. Let the turn run normally.
6. Check Codex usage afterward.
7. Observe the 5-hour allowance depleted or effectively exhausted after the single turn while weekly usage still has substantial remaining capacity.

What is the expected behavior?

A single detailed prompt should not consume the entire 5-hour subscription window unless the underlying compute genuinely warrants that amount, and the product should make that consumption understandable before or immediately after the task.

If long prompt/context size materially changes quota consumption, Codex should ideally provide:

• per-turn usage attribution;
• input/cached-input/output/reasoning token visibility;
• the percentage of the 5-hour allowance consumed by that turn;
• a warning when a submitted task is likely to consume most or all of the current 5-hour allowance;
• clearer documentation of how long input context and Max reasoning are weighted against the rolling quota.

Additional information

This appears related to other recent reports of GPT-5.6 Sol rapidly consuming 5-hour quota, but this report is specifically about a repeatable single-prompt trigger: one structured prompt above roughly 15k characters exhausting the 5-hour window.

The workflow does not require a public repository, production deployment, or unusually large generated artifact to reproduce.

No source files or tests are identified. Start by reproducing the report with Codex CLI 0.150.1, a ChatGPT Plus account, GPT-5.6 Sol at Max reasoning, and a prompt above roughly 15k characters; compare usage before and after the turn and document whether quota attribution or warning behavior is available.