[BUG] Wrong endpoint hostname when using Google's Vertex AI with region "global" for Claude models #8571
Description
Problem (one or two sentences)
When Roo Code is configured to use Google's Vertex AI provider, with the Google Cloud Region set to "global" and choosing an Anthropic Claude LLM as the model (e.g., sonnet-4), Roo tries to hit a non-existent hostname getting 404 errors (to be clear, the Claude model is enabled in the GCP project being used).
We see this in the debug logs on the Extension Host:
... ProxyResolver#resolveProxy unconfigured https://global-aiplatform.googleapis.com/v1/projects/.../locations/global/publishers/anthropic/models/claude-sonnet-4@20250514:streamRawPredict DIRECT
leading to this error in the UI:
<p><b>404.</b> <ins>That’s an error.</ins>
<p>The requested URL <code>/v1/projects/.../locations/global/publishers/anthropic/models/claude-sonnet-4@20250514:streamRawPredict</code> was not found on this server. <ins>That’s all we know.</ins>
(This error doesn't happen when using a Gemini model, nor when using a Claude model in a specific region other than "global".)
The correct hostname for the "global" endpoint is aiplatform.googleapis.com, not global-aiplatform.googleapis.com.
Context (who is affected and when)
Reproduction steps
Expected result
No error
Actual result
404 error
Variations tried (optional)
No response
App Version
v3.28.15
API Provider (optional)
Google Vertex AI
Model Used (optional)
Any Claude model
Roo Code Task Links (optional)
No response