Title: Windows Codex transport closes after successful Unity MCP connect on read-only tool calls

[ibytergj]

Environment

• OS: Windows
• Codex release version: 26.325.21211
• Unity: 6000.3.12f1
• Unity MCP plugin: 2.25.0
• Unity MCP server: 2.27.0

Summary
The Unity MCP connection succeeds at first, but certain read-only tool calls cause the MCP transport to close.

Observed behavior

• unity_list_instances succeeds
• unity_select_instance succeeds
• unity_editor_ping succeeds
• unity_scene_info fails with Transport closed
• unity_editor_state also fails with Transport closed
• After that, later MCP calls can continue failing with Transport closed until the MCP/server is restarted

Expected behavior
Read-only calls like unity_scene_info and unity_editor_state should return data without killing the transport.

Repro

1. Start Unity
2. Start/restart the Unity MCP bridge/server
3. Call unity_list_instances
4. Call unity_select_instance
5. Call unity_editor_ping
6. Call unity_scene_info

Result
The transport closes on unity_scene_info.

Notes

• The Unity bridge starts successfully
• Instance discovery works
• The editor is reachable before the failure
• This does not appear to be an initial connection problem; it happens after a successful connection

Version mismatch possibly relevant

• Plugin package version: 2.25.0
• Server package version: 2.27.0
• Server manifest version appears to differ from package version

[francoios]

Hi,

Since we aren't codex users we cannot explore a solution for the moment, so i encourage you on trying to find one that works for you, and that doesn't break current claude code / desktop implementation. then we would be glad to merge it.

[SABERBOY]

if you change the code in src/unity-editor-bridge.js it will work fine in codex

[Alinccc]

if you change the code in src/unity-editor-bridge.js it will work fine in codex

I am using codex under the window system. According to your modification, the Transport Closes problem can be fixed.