[BUG] 500 No available Claude accounts support the requested model: claude-sonnet-4-5

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?

Issue details:

I've been using claude-sonnet-4-5 model previously without issues

Other models like Opus and Haiku work normally when selected

I've tried multiple troubleshooting steps:

Exiting (/exit) and re-entering doesn't fix it

Closing the command window and reopening doesn't help

Updated to the latest package via npm update -g @anthropic-ai/claude-code - still broken

During the same time period, others have tested the same configuration and it works fine for them

The issue appears to be isolated to my environment/system

Environment:

OS: Windows

Claude Code CLI version: v2.1.12 (latest)

Node.js version: v24.11.1

Additional context:
This seems to be a model-specific issue, as switching to other models works. The claude-sonnet-4-5 model appears to be unavailable or incorrectly configured in my CLI setup.

What Should Happen?

Normal conversation should start using the Claude 4-5 Sonnet model without any errors.

Error Messages/Logs

╭─── Claude Code v2.1.12 ──────────────────────────────────────────────────────────────────────────────────────────────────╮
│                                           │ Tips for getting started                                                     │
│               Welcome back!               │ Run /init to create a CLAUDE.md file with instructions for Claude            │
│                                           │ Note: You have launched claude in your home directory. For the best experie… │
│                  ▐▛███▜▌                  │ ──────────────────────────────────────────────────────────────────────────── │
│                 ▝▜█████▛▘                 │ Recent activity                                                              │
│                   ▘▘ ▝▝                   │ No recent activity                                                           │
│                                           │                                                                              │
│   claude-sonnet-4-5 · API Usage Billing   │                                                                              │
│              C:\Users\86185               │                                                                              │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
  /model to try Opus 4.5

> hello
  ⎿  500 No available Claude accounts support the requested model: claude-sonnet-4-5
     Retrying in 0 seconds… (attempt 4/10)

✻ Nucleating… (ctrl+c to interrupt)

Steps to Reproduce

1. Open a command prompt window (even after multiple restarts)
2. Run claude --version to confirm version (v2.1.12)
3. Enter the command claude to launch the CLI dialogue interface
4. Send a simple message like hello
5. Observe the 500 error immediately appears

Note: The issue occurs every single time on my machine. Switching to other models with /model opus or /model haiku works as a workaround.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

Unknown

Claude Code Version

v2.1.12 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_