[BUG] Unexpected usage spike — 0% to 17% from minimal usage

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

My daily usage quota is being consumed at a highly disproportionate rate. After only a single, brief query (checking two files), the usage jumped from 0% to 17%. This happened yesterday as well, and after verifying it again today, it is clear that this is a recurring issue. At this rate, the service is virtually unusable as the quota would be exhausted in just a few simple questions.

What Should Happen?

For a simple "grep and read" task involving only two files in a new session, the usage should be minimal (well under 1%). The metering should accurately reflect the actual computational cost and token usage of the request.

Error Messages/Logs

Steps to Reproduce

1. Confirm daily usage is at 0% at the start of a new session.
2. Provide Claude with access to a codebase/files.
3. Submit a single, short query: "Check if delete logic for a specific custom object exists in [File A] and [File B]."
4. Check the "Usage" indicator immediately after Claude’s response.
5. Observe the 17% (or similar excessive) increase from a single interaction.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

 2.1.126

Claude Code Version

 2.1.126

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_