[Bug] Desktop app spawns every local stdio MCP server twice at session start #41331

Summary

The opencode desktop app (@opencode-aidesktop, Electron) spawns two copies of every local stdio MCP server at session start. Both copies appear within ~5 seconds of each other, as children of the same OpenCode utility (node) process. Reproduced across two consecutive app restarts.

Environment

• App: opencode desktop 1.18.15 (C:\Users\rusla\AppData\Local\Programs\@opencode-aidesktop\OpenCode.exe)
• OS: Windows 11
• Config: 12 MCP servers in ~/.config/opencode/opencode.json (mix of npx and Python/uvx/binary commands)
• Reproducible: yes, 2/2 restarts

Evidence (after fresh restart, all timestamps same boot)

Every local MCP server appears in two waves ~5s apart, all under the same app utility process:

OpenCode.exe (main 20748) 0:06:42
 └─ utility node 6588
     ├─ github-mcp-server 25496  0:06:48   (WAVE 1)
     └─ github-mcp-server 21820  0:06:53   (WAVE 2)
     ├─ npx @playwright/mcp@0.0.79 → cli.js ×2
     ├─ npx server-filesystem      → index.js ×2
     ├─ npx server-sequential-thinking → dist/index.js ×2
     └─ (uvx mcp-pandoc also ×2: 22620, 23732)

Same pattern was present in the previous session (1.18.10-era processes), i.e. it persists across versions.

Expected behavior

Each configured MCP server should spawn exactly once per session.

Actual behavior

2 copies per server → double memory (~200–300 MB wasted), and for stateful stdio servers (memory stores writing JSONL/SQLite, browsers holding ports) two live writers create race/corruption risk.

Related

• [Bug] Web UI spawns duplicate MCP server waves during active session #9230 "[Bug] Web UI spawns duplicate MCP server waves during active session" — same bug class, auto-closed after 90 days of inactivity, never fixed (auto-close comment says "open a new one").
• Local stdio MCP servers leak processes on disconnect / replace / rollback #26714 process leaks on disconnect/replace/rollback (different path).

Happy to provide full PID/PPID dumps or run an instrumented build.