[BUG]: Severe latency when invoking agents via @mention in Desktop App (Windows) #31293

Description

There is a severe performance issue when invoking agents using the @mention syntax in the OpenCode Desktop app on Windows. While primary agents respond normally (still slower compare to other apps), any agent invoked as a subagent (via @) takes an excessive amount of time to respond sometimes between 2 to 4 minutes even for extremely simple prompts (e.g., "Who are you?").

This happens regardless of whether the agent is defined as a Global Agent (in ~/.config/opencode/agents/) or a Per-Project Agent (in .opencode/agents/).

It doesn't matter what model I use, all have the same issue.
Without using @Agent_Name the speed is normal, still much slower than other apps but not as slow as using an Agent.

Expected Behavior

The agent should be invoked and respond within a reasonable timeframe (e.g., 10-30 seconds), similar to the primary agent's response time.

Actual Behavior

The application hangs or delays the response for several minutes before the subagent finally answers.

Environment & Specs:

• OS: Windows 11 Pro
• Agent Type: Both Global and Per-Project agents exhibit the same lag.

• Intel Core Ultra 9 285K
• Nvidia RTX 5090 32 GB VRAM
• 96 GB RAM 6400 Mhz
• Nvme SSD

OpenCode version

OpenCode Desktop v1.16.2

Steps to reproduce

1. Create a simple agent in .opencode/agents/test.md or ~/.config/opencode/agents/test.md.
2. Set the agent mode to subagent.
3. Restart the OpenCode Desktop application.
4. In the chat, type @test followed by a simple question like "Hello".
5. Observe the time it takes for the agent to start responding.

Operating System

Windows 11