[BUG] Claude code - Incorrect cost reporting in non interactive mode with `resume`

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?

• Running /cost inside an interactive Claude Code session shows correct accumulated cost/usage.
• Running the equivalent in non-interactive mode with resume (e.g., claude -p /cost --output-format json --resume <session-id>) returns $0.0000 and near-zero/empty usage, even though the session has prior usage.

Example observed output:

Total cost: $0.0000\nTotal duration (API): 0s\nTotal duration (wall): 3s\nTotal code changes: 0 lines added, 0 lines removed\nUsage: 0 input, 0 output, 0 cache read, 0 cache write

What Should Happen?

claude -p /cost --resume <session-id> should report the same accumulated totals as /cost does inside the interactive session for that session id (non-zero cost and model usage where applicable).

Error Messages/Logs

Steps to Reproduce

1. Start a session with a fixed session id:

claude --session-id 00000000-0000-0000-0000-000000000000

1. Prompt to do something
2. In the interactive session, run:

/cost

Confirm it reports non-zero cost/usage

1. Exit the session
2. Run the non-interactive resumed command:

claude -p /cost --output-format json --verbose --resume 00000000-0000-0000-0000-000000000000

1. Observe that it reports $0.0000 (and/or empty usage).

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.75

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

<img width="1728" height="1117" alt="Image" src="https://github.com/user-attachments/assets/6e6abda6-c0ad-4d93-a526-44befe94f815" />