TypeError: .pendingRequests[0].request.message.parts: Converting circular structure to JSON

Does this issue occur when all extensions are disabled?: No? copilot is builtin

- VS Code Version:
- OS Version:

```ts
[Window Title]
Visual Studio Code

[Main Instruction]
Visual Studio Code

[Content]

Version: 1.128.0 (system setup)
Commit: fc3def6774c76082adf699d366f31a557ce5573f
Datum: 2026-07-07T15:14:24-07:00 (Vor 4 Tagen)
Electron: 42.5.0
ElectronBuildId: 14525058
Chromium: 148.0.7778.271
Node.js: 24.17.0
V8: 14.8.178.33-electron.0
Betriebssystem: Windows_NT x64 10.0.26200

[Kopieren] [OK]
```

Steps to Reproduce:

1. running agent
2. submit `/fork`

Fehler beim Serialisieren der Chatsitzung für den Speicher. Die Sitzung geht verloren, wenn das Fenster geschlossen wird. Melden Sie dieses Problem an das VS Code Team:
```ts

TypeError: .pendingRequests[0].request.message.parts: Converting circular structure to JSON
--> starting at object with constructor 'a'
| property 'negated' -> object with constructor 'a'
--- property 'negated' closes the circle
--> starting at object with constructor 'a'
| property 'negated' -> object with constructor 'a'
--- property 'negated' closes the circle
--> starting at object with constructor 'a'
| property 'negated' -> object with constructor 'a'
--- property 'negated' closes the circle
--> starting at object with constructor 'a'
| property 'negated' -> object with constructor 'a'
--- property 'negated' closes the circle
--> starting at object with constructor 'a'
| property 'negated' -> object with constructor 'a'
--- property 'negated' closes the circle
--> starting at object with constructor 'a'
| property 'negated' -> object with constructor 'a'
--- property 'negated' closes the circle
at JSON.stringify ()
at XSe (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3022:160)
at $Ln (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3022:293)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:412)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:917)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:765)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:847)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:765)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:847)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:765)
at vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:531
at Array.map ()
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:506)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:847)
at Object.extract (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3021:765)
at m7.write (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3023:701)
at Hse.writeSession (vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3025:12705)
at vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3025:9686
at Array.map ()
at vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:3025:9674
at vscode-file://vscode-app/c:/Program%20Files/Microsoft%20VS%20Code/fc3def6774/resources/app/out/vs/workbench/workbench.desktop.main.js:434:73973
```