[BUG] ollama: model prefix not stripped from API request body

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?

When using --model ollama:<model>, Claude Code sends the full prefixed name (e.g. ollama:qwen3-coder) in the model field of the API request body instead of stripping the ollama: provider prefix. Ollama doesn't recognize the prefixed name and returns a 404:

{"type":"error","error":{"type":"not_found_error","message":"model 'ollama:qwen3-coder' not found"}}

Verified by curling the Ollama /v1/messages endpoint directly:

# Fails (404) — this is what Claude Code sends:
curl "http://<host>:11434/v1/messages?beta=true" -d '{"model":"ollama:qwen3-coder",...}'

# Works (200) — correct model name:
curl "http://<host>:11434/v1/messages?beta=true" -d '{"model":"qwen3-coder",...}'

What Should Happen?

Claude Code should strip the ollama: provider prefix before including the model name in the API request body, same as how the base URL is resolved from the prefix.

Error Messages/Logs

Claude Code shows:

There's an issue with the selected model (ollama:qwen3-coder). It may not exist or you may not have access to it. Run /model to pick a different model.

Ollama server logs:

[GIN] 2026/03/12 - 15:22:21 | 404 |   67.365286ms |  176.148.64.230 | POST     "/v1/messages?beta=true"

Steps to Reproduce

1. Have Ollama running on a remote (or local) machine with a model pulled (e.g. qwen3-coder)
2. Run:

``bash
ANTHROPIC_AUTH_TOKEN=ollama ANTHROPIC_API_KEY="" ANTHROPIC_BASE_URL=http://<host>:11434 claude --model ollama:qwen3-coder
``

1. Send any message
2. Get the "issue with the selected model" error

Workaround

Create an Ollama model alias matching the prefixed name:

ollama cp qwen3-coder "ollama:qwen3-coder"

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.74 (Claude Code)

Platform

Anthropic API

Operating System

Linux (Arch)

Terminal/Shell

Kitty

Additional Information

Ollama version: 0.17.7
Remote model: qwen3-coder (30B)