[BUG] Resumed sessions attribute new token usage to the original session-creation date in Desktop Model Usage view

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

When a session is resumed days after its creation, all token usage generated during the resumed conversation is reported under the original session-creation date instead of the actual date the tokens were consumed. This is visible in the Claude desktop app under Settings → Usage / Model Usage, where the daily totals roll up onto the wrong calendar day. The status line / context counter inside Claude Code reflects the same misattribution. The result is that "today's" usage looks artificially low and a past day appears to retroactively gain usage that did not occur on that day.

What Should Happen?

Token usage should be attributed to the calendar date on which the tokens were actually consumed (the date of each individual request/response), not the date the session was originally created. Resuming an old session via claude --resume should add today's tokens to today's bucket in the Desktop Model Usage view (and any other usage surfaces).

Error Messages/Logs

N/A — no error is produced. This is a reporting/attribution bug, not a runtime failure.

Steps to Reproduce

1. On Day 1, run claude to start a new session in any directory. Send one or more prompts so token usage is recorded. Exit.
2. Open the Claude desktop app → Settings → Usage / Model Usage. Note Day 1's totals. Confirm Day 2 (and subsequent days) show 0 tokens for this work.
3. Wait at least 24 hours (a longer gap, e.g. 3–5 days, makes the misattribution more obvious).
4. On Day N (N ≥ 2), run claude --resume and select the session created on Day 1. Send several new prompts so a meaningful number of tokens is consumed today.
5. Exit, then reopen the Claude desktop app → Settings → Usage / Model Usage.

Observed: Day 1's total has grown by the tokens just consumed on Day N. Day N still shows 0 (or only shows tokens from non-resumed sessions started today).
Expected: Day N's total should reflect the tokens consumed today; Day 1's total should be unchanged after Day 1 ended.

This is fully deterministic and reproduces every time on a freshly resumed old session.

Claude Model

Not sure / Multiple models (reproduces regardless of model selection)

Is this a regression?

I don't know

Claude Code Version

2.1.123 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

• macOS 26.4.1 (Darwin 25.4.0, arm64)
• Shell: zsh
• The bug is purely in usage reporting/attribution; the conversation itself resumes correctly and the API requests succeed normally.
• The misattribution is consistent between the in-CLI status display and the Desktop app's Model Usage overview, suggesting both surfaces source the per-day totals from the session's creation timestamp rather than per-request timestamps.