Long reasoning text cut off (apparent character limit)

Summary:

When the model thinks for a long time and produces very long reasoning text, the displayed reasoning text stops mid-sentence. The model is still "thinking," but no further reasoning text is generated or displayed. This suggests a character limit on the reasoning text.

Steps to Reproduce:

1. Send a prompt that causes the model to "think" for an extended period with very long reasoning.

2. Watch the reasoning text while the model is still "thinking."

Actual Result:

The reasoning text is cut off mid-sentence. The model is still "thinking," but no additional reasoning text is generated or displayed.

Expected Result:

The reasoning text should stream continuously until the model finishes thinking, without being truncated mid-sentence.