LiteLLM - Incorrect `baseURL` handling in LiteLLM provider when a path is included

[ChuKhaLi]

App Version

3.23.8 (65a82fd)

API Provider

LiteLLM

Model Used

N/A

Roo Code Task Links (Optional)

No response

🔁 Steps to Reproduce

1. Configure the litellm provider in VSCode settings with a baseURL that includes a path, for example http://localhost:4000/litellm
2. Click Refresh Models
3. Roo Code UI show error like Failed to fetch LiteLLM models: Failed to fetch LiteLLM models: Unexpected response format.

💥 Outcome Summary

Expected: Request should go to http://localhost:4000/litellm/v1/model/info for model fetching and
Actual: Path component is dropped, requests go to http://localhost:4000/v1/model/info

📄 Relevant Logs or Errors (Optional)

Failed to fetch LiteLLM models: Failed to fetch LiteLLM models: Unexpected response format.

[dosubot]

Hi @ChuKhaLi! I'm Dosu and I’m helping the Roo-Code team.

There isn't any explicit documentation or troubleshooting guidance on handling LiteLLM baseURL values that include a path in Roo Code. The docs state that model info is fetched from ${baseUrl}/v1/model/info, but don't clarify how paths in the baseURL are handled or mention any known issues with this scenario. There was a previous bug fix for trailing slashes in the LiteLLM provider, which suggests URL handling has been problematic before, but nothing specifically about dropping path components like you're seeing source source.

No workarounds or configuration tips for this case are documented. You might try experimenting with different baseURL formats (with or without a trailing slash), but based on the available info, this looks like an unaddressed bug or limitation in the current implementation. If you need this functionality, keep an eye on future updates or changelogs for a fix.

To reply, just mention @dosu.

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[ChuKhaLi]

@dosu in file src\api\providers\fetchers\litellm.ts line 27, the url to fetch model is construct in a way that will drop the url path

[dosubot]

You're right—there's no documentation or workaround for this, but the way the URL is built in that file likely uses the URL constructor or similar logic that, when given a path in the baseURL and then appending a new path (like /v1/model/info), will drop the original path component if not handled carefully. This is a common pitfall in JavaScript/TypeScript: using new URL('/v1/model/info', baseUrl) will replace the path instead of joining it, so a baseURL like http://localhost:4000/litellm ends up as http://localhost:4000/v1/model/info, dropping /litellm.

This isn't covered in the docs, and there aren't any config tips or fixes published yet—it's an unaddressed bug or limitation in the current implementation. If you need this fixed, keep an eye on future changelogs or consider patching the URL joining logic to preserve the path segment when constructing the endpoint URL. For reference, the docs just state the endpoint is built as ${baseUrl}/v1/model/info without clarifying path handling or troubleshooting this scenario (source).

To reply, just mention @dosu.

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[ChuKhaLi]

Fix by #5697