Gemini Pro 3: Server error. Stream terminated when used after other models in the same conversation

[chryzxc]

Issue: Gemini Pro 3 returns Server error. Stream terminated when used after other models in same conversation

Summary

When using Gemini Pro 3 in VS Code Copilot Chat, the model frequently stops mid-response and shows the error:

Server error. Stream terminated

This only occurs when the conversation includes previous messages from other models (e.g., GPT-5.1, Claude Sonnet 4.5, Claude Opus).
When starting a new chat with no prior context, Gemini Pro 3 works normally.

This suggests an issue with mixed-model conversation context or model switching within a thread.

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Steps to Reproduce

1. Open VS Code Copilot Chat.
2. Start a long conversation using another model (e.g., GPT-5.1, Sonnet 4.5).
3. After a few exchanges, switch the model to Gemini Pro 3.
4. Ask any moderately complex question.
5. The response stops halfway and the error appears:
   Server error. Stream terminated

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Expected Behavior

Gemini Pro 3 should complete responses normally, regardless of which models were used earlier in the conversation.

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Actual Behavior

Gemini Pro 3 terminates the stream mid-response with a server error when used in a chat that contains previous messages from other models.

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Environment

• VS Code version: 1.106.3
• OS: Windows
• Network: Wired / Wireless
• Workspace type: (any project)

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Additional Notes

• Issue is not related to token limits (happens even with short prompts).
• No rate-limit or network warnings.
• Issue disappears completely when using a new chat with no prior model context.

[MessyComposer]

Happening to me even without changing the model and only using Gemini 3 Pro from the beginning. Just stops working after a few prompts.

[jwulf]

This happens to me when I am telling it to make changes and it is in plan mode. As soon as it gets to to the part where it wants to write code, I get this error message.

Making sure to change it to Agent mode fixes the error.

[McPandaSmp]

Same for me

[Programmer-Red]

same, but other model is normal

[pickJC]

same, 2026-01-19

[uyrabi]

same here , it just happened