[BUG] Claude Code using Sonnet 4.5 despite Haiku 4.5 being configured everywhere

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?

Claude Code is using the Sonnet 4.5 model and charging me accordingly, even though I have Haiku 4.5 configured everywhere in my settings. The CLI shows "Haiku 4.5" as the selected model, but my API billing shows Sonnet 4.5 usage.

What Should Happen?

Claude Code should use the Haiku 4.5 model as configured, and billing should reflect Haiku 4.5 token usage (which is significantly cheaper than Sonnet 4.5).

Error Messages/Logs

Steps to Reproduce

Configure Claude Code to use Haiku 4.5 model
Use Claude Code from either terminal (Arch Linux) or IDE (PhpStorm)
Verify CLI shows "Haiku 4.5 · API Usage Billing"
Check Anthropic API billing dashboard
Observe Sonnet 4.5 usage appears in billing instead of configured Haiku 4.5

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.26

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

IntelliJ IDEA terminal

Additional Information

<img width="445" height="199" alt="Image" src="https://github.com/user-attachments/assets/f2974b31-228a-4703-9c0e-92fc71eb35e9" />

<img width="841" height="150" alt="Image" src="https://github.com/user-attachments/assets/a5d5533f-1580-4891-8545-990729a62feb" />

<img width="1269" height="677" alt="Image" src="https://github.com/user-attachments/assets/6608ac8e-0d07-4c75-aa06-59b616b7cc32" />

<img width="1192" height="609" alt="Image" src="https://github.com/user-attachments/assets/6b79cb8a-1991-40fb-947e-c2fff0c1e687" />

<img width="1207" height="575" alt="Image" src="https://github.com/user-attachments/assets/9729922b-bb00-4a31-b96c-3a7aa07c193c" />