Terminal flickers and scroll jumps between top and bottom during MCP loading and agent iteration in Visual Studio

[max-montes]

Describe the bug

CopilotCLIFlickerRepro.mp4

When using Copilot CLI in Visual Studio's integrated terminal (PowerShell 7), the entire terminal flickers and rapidly alternates between the topmost scroll position and the bottom of the terminal. This occurs in two scenarios:

1. During MCP server loading — when the CLI initializes and loads MCP server connections at startup
2. During agent iteration — when the agent is actively making tool calls and processing responses

The flickering is a rapid scroll-jumping behavior where the terminal view alternates between the very top of the scroll buffer and the current bottom position, creating a disorienting strobe effect.

This is different from #1298 (command prompt area flashing while typing). This issue involves the entire terminal viewport jumping scroll positions during active agent work.

Affected version

GitHub Copilot CLI 0.0.421-1

Steps to reproduce the behavior

1. Open Visual Studio (not VS Code) with the integrated terminal (PowerShell 7)
2. Start Copilot CLI with MCP servers configured
3. Observe flickering during MCP server initialization
4. Send a prompt that causes the agent to iterate with multiple tool calls (e.g., multi-file code generation)
5. Observe the terminal rapidly flickering/jumping between the top and bottom of the scroll buffer

Expected behavior

The terminal should render smoothly without scroll position jumping. The viewport should stay anchored at the bottom where new output is being written.

Additional context

• IDE: Visual Studio (not VS Code)
• Terminal: Integrated terminal using PowerShell 7
• OS: Windows
• Workaround: Using Windows Terminal or VS Code terminal does not exhibit this behavior

Screen recording: (I will attach a video demonstrating the issue)

Related issues

• Terminal flashing/flickering in Visual Studio integrated terminal #1298 — Terminal flashing/flickering while typing (different behavior — prompt area flash vs. scroll jumping)
• VS Code crashes (EXC_BREAKPOINT) when toggling subagent visibility during active subagent run #1578 — VS Code crash from flickering during subagent toggle