[Usage][Luna] Weekly Codex limit dropped ~40% in one day despite light usage #39818

What version of the Codex App are you using (From “About Codex” dialog)?

Latest Windows Codex App update available on 2026-08-21. Exact build number was not captured before filing.

What subscription do you have?

ChatGPT plan with Codex access.

What platform is your computer?

Windows desktop Codex app.

What issue are you seeing?

After the recent Codex update, my weekly Codex usage dropped from roughly 100% remaining to about 60% remaining in a single day, despite doing comparatively little work and using GPT-5.6 Luna.

The amount of work performed was less than half of a previous period in which I eventually consumed the full weekly allowance. The current session therefore appears to be consuming quota far faster than my established baseline.

This is particularly unexpected because the work was performed with Luna, which is intended to have substantially lower usage/credit cost than Sol.

What steps can reproduce the bug?

1. Open Codex on Windows after the latest available update.
2. Select GPT-5.6 Luna.
3. Perform normal development work on an existing project.
4. Avoid intentionally heavy usage such as large-scale repository-wide refactors or prolonged high-cost model runs.
5. Check weekly usage before and after the work session.
6. Observe a much larger drop than expected relative to prior usage patterns.

What is the expected behavior?

Luna usage should consume the weekly Codex allowance materially more slowly than Sol for comparable work, and normal/light development activity should not reduce the weekly allowance by approximately 40 percentage points in one day when the workload is substantially below a previous full-week workload.

Actual behavior

• Approximately 40% of the weekly allowance was consumed within about one day.
• Remaining allowance is approximately 60%.
• The workload was less than half of a prior period that eventually consumed the entire allowance.
• GPT-5.6 Luna was used for the work.
• The perceived consumption rate is dramatically higher than the user's prior baseline.

Additional information

This may be related to existing usage-accounting reports, but I am filing a separate report because the magnitude and timing are easy to distinguish from my prior baseline.

Potentially related:

• Luna usage draining codex usage at the same speed as Sol despite no difference in the way it's used #36801 — Luna draining Codex usage at a similar rate to Sol
• Weekly limit is draining like the old 5-hour limit #33685 — weekly limit draining unusually quickly
• Credit usage ledger frozen since Aug 8, 2026 — 45,252 of 53,000 purchased credits (85.4%) consumed with zero usage records; ongoing #39260 — credit/usage ledger discrepancies

I cannot confirm whether the cause is model weighting, background activity, or server-side usage accounting. The main reproducible observation is the sharp change in weekly-limit consumption immediately after the recent update while using Luna for a relatively light amount of work.

If useful, please expose per-session/per-model quota attribution so users can distinguish foreground Luna requests from background/sub-agent/tool activity and verify what consumed the weekly allowance.