Azure MCP learn=true calls time out after 180s in Copilot CLI 1.0.83-5

Describe the bug

Azure MCP hierarchical tool discovery calls using learn=true consistently time out after 180 seconds in Copilot CLI 1.0.83-5. The same calls complete in about 0.2 seconds under CLI 1.0.80.

Direct Azure MCP child-command calls without learn=true still succeed, which isolates the regression to hierarchical tool discovery rather than MCP startup, authentication, or general Azure connectivity.

Affected version

GitHub Copilot CLI 1.0.83-5
Windows executable file/product version: 1.0.83-5

Steps to reproduce the behavior

1. Configure the Microsoft Azure MCP server and confirm it connects.
2. Start Copilot CLI 1.0.83-5.
3. Ask the agent to make exactly one Azure Kusto MCP call with: {"intent":"Discover the Kusto command contract","learn":true}
4. Observe that the call remains pending for 180 seconds and fails with: MCP server 'azure': McpError: MCP error -32001: Request timed out
5. Repeat with Azure get_azure_bestpractices and learn=true; it fails the same way.
6. Run the same probes with CLI 1.0.80; both discovery calls succeed immediately.

Controlled A/B results:

The fresh Kusto and Best Practices A/B probes were launched simultaneously under both CLI versions with the same model, workspace, MCP configuration, and machine. All probe stderr logs were empty.

Expected behavior

learn=true should return the hierarchical tool command schema promptly, as it does under CLI 1.0.80, instead of reaching the client's 180-second timeout.

Additional context

• OS: Windows 11 Enterprise 23H2, build 22631
• Architecture: AMD64
• Shell: PowerShell 7.6.5
• Terminal: VS Code integrated terminal
• Azure MCP reached connected before each probe
• Reproduced 3/3 times on 1.0.83-5
• Control succeeded 3/3 times on 1.0.80
• No exact duplicate found in the open or closed github/copilot-cli issues

从 Copilot CLI 的 MCP 层次化工具发现路径开始，在 1.0.83-5 和 1.0.80 版本上使用 learn=true 重现报告中的 Azure 调用。比较发现行为，同时确认直接调用子命令仍然成功；完成标准是两个层次化探测都能及时返回其 schema，而不是在 180 秒后超时。