Copilot Chat: Agent loops when reading a ~500-line file
Author: kh4fCreated Oct 2, 2026Updated Oct 2, 2026
After recent VS Code Insiders updates, some models can get stuck in an infinite loop when reading a moderately sized file.
Repro
- Clone https://github.com/kh4f/flexplorer
- Open it in VS Code and attach
src/core/dnd-engine.tsto the chat. - Select
deepseek-v4.1-flashorglm-5.3-flashin agent mode. - Send:
On mobile devices, make dragging start only after a 1-second long press on the drag handle
Expected
The agent should be able to read a 497-line / 17.8 KB file, either in one call (via "forceReadLargeFiles": true) or by reading appropriate ranges/chunks.
Actual
The agent gets confused and keeps re-reading the same file indefinitely.
Logs
| Model | Chat Debug Logs (.copilotmd) | Exported Chat (.json) |
|---|---|---|
| DeepSeek V4.1 Flash | deepseek-v4.1-flash.copilotmd | deepseek-v4.1-flash.json |
| GLM 5.3 Flash | glm-5.3-flash.copilotmd | glm-5.3-flash.json |
Environment
...Initial Environment (bug discovered):
Version: 1.141.0-insider (user setup)
Commit: ec2e580674cdb512aa9b2a9596ab35d8a9590f1e
Date: 2026-10-01T04:00:54Z
Electron: 43.7.3
ElectronBuildId: 15386805
Chromium: 150.0.7871.250
Node.js: 24.21.0
V8: 15.0.245.31-electron.0
@github/copilot: 1.0.90
@github/copilot-sdk: 1.0.16
OS: Windows_NT x64 10.0.26200Updated Environment (the issue persists):
Version: 1.141.0-insider (user setup)
Commit: de892dd1f9971e3a7d8c758a8788d86854047605
Date: 2026-10-02T04:07:15Z
Electron: 43.7.3
ElectronBuildId: 15386805
Chromium: 150.0.7871.250
Node.js: 24.21.0
V8: 15.0.245.31-electron.0
@github/copilot: 1.0.92-0
@github/copilot-sdk: 1.0.17-preview.0
OS: Windows_NT x64 10.0.26200Source: microsoft/vscode