Integrated terminal: Ctrl+C no longer interrupts running processes (regression in Insiders)

[howmanysmall]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.110.0-insider (0366405)
• OS Version: macOS 26.1 (Build 25B78)

Steps to Reproduce:

1. Open the integrated terminal in VS Code Insiders.
2. Use fish as the integrated terminal shell (fish at /opt/homebrew/bin/fish).
3. Run sleep 100 (also seen with top).
4. Press Ctrl+C.

Expected:

sleep is interrupted (SIGINT) and the shell prompt returns.

Actual:

The process keeps running, and the terminal prints something like [99;5u (sometimes repeated).

Additional Information:

• Only reproduces with fish (fish 4.4.0). If I switch the integrated terminal profile to zsh, Ctrl+C works normally.
• Outside VS Code, Ctrl+C interrupts as expected in fish (Ghostty and macOS Terminal).
• $TERM:
  • VS Code: xterm-256color
  • Ghostty: xterm-ghostty
  • macOS Terminal: xterm-256color (Ctrl+C works)
• Ctrl+C also does nothing at the fish prompt (no running command).
• Disabling shell integration (terminal.integrated.shellIntegration.enabled: false) does not change the behavior.
• Reproducible with fish --no-config.
• fish_key_reader prints bind ctrl-c 'do something' in both VS Code and Ghostty.
• [99;5u looks like a kitty keyboard protocol "CSI u" sequence for Ctrl+C.

Repro videos:

CleanShot.2026-02-14.at.14.07.27.mp4

CleanShot.2026-02-14.at.14.09.28.mp4

[howmanysmall]

Whoops, sorry, did this from CLI so it didn't seem to follow the template.

[shyim]

This drives me crazy.

Maybe an easier reproducer:

npx concurrently -- 'sleep 50' 'sleep 50'

you cannot control + c to escape 😭 .

[meganrogge]

Cannot repro, thus closing. Try using Developer: Toggle Keyboard Shortcuts Troubleshooting to debug

bug-no-repro.mov

no-repro2.mov

[shyim]

2026-02-17 19:04:13.761 [info] [Window] [KeybindingService]: / Received  keydown event - modifiers: [ctrl], code: ControlLeft, keyCode: 17, key: Control
2026-02-17 19:04:13.761 [info] [Window] [KeybindingService]: | Converted keydown event - modifiers: [ctrl], code: ControlLeft, keyCode: 5 ('Ctrl')
2026-02-17 19:04:13.761 [info] [Window] [KeybindingService]: \ Keyboard event cannot be dispatched in keydown phase.
2026-02-17 19:04:13.976 [info] [Window] [KeybindingService]: / Soft dispatching keyboard event
2026-02-17 19:04:13.976 [info] [Window] [KeybindingService]: | Resolving ctrl+[KeyC]
2026-02-17 19:04:13.976 [info] [Window] [KeybindingService]: \ No keybinding entries.
2026-02-17 19:04:14.064 [info] [Window] [KeybindingService]: / Soft dispatching keyboard event
2026-02-17 19:04:14.065 [info] [Window] [KeybindingService]: | Resolving ctrl+[KeyC]
2026-02-17 19:04:14.065 [info] [Window] [KeybindingService]: \ No keybinding entries.
2026-02-17 19:04:14.383 [info] [Window] [KeybindingService]: / Soft dispatching keyboard event
2026-02-17 19:04:14.384 [info] [Window] [KeybindingService]: | Resolving ctrl+[KeyC]
2026-02-17 19:04:14.384 [info] [Window] [KeybindingService]: \ No keybinding entries.
2026-02-17 19:04:14.508 [info] [Window] [KeybindingService]: / Soft dispatching keyboard event
2026-02-17 19:04:14.509 [info] [Window] [KeybindingService]: | Resolving ctrl+[KeyC]
2026-02-17 19:04:14.509 [info] [Window] [KeybindingService]: \ No keybinding entries.
2026-02-17 19:04:14.531 [info] [Window] [KeybindingService]: / Soft dispatching keyboard event
2026-02-17 19:04:14.531 [info] [Window] [KeybindingService]: \ Keyboard event cannot be dispatched
2026-02-17 19:04:14.531 [info] [Window] [KeybindingService]: + Ignoring single modifier ctrl due to it being pressed together with other keys.

[shyim]

Asked Claude:

The sequence ^[[99;5u is the Kitty Keyboard Protocol encoding of Ctrl+C:

• 99 = Unicode codepoint for c
• 5 = Ctrl modifier
• u = CSI u format terminator

VS Code recently enabled the Kitty Keyboard Protocol by default (commit 8c3168c on Feb 11, 2026) via the setting terminal.integrated.enableKittyKeyboardProtocol. Your shell (fish) doesn't fully understand this protocol, so
instead of interpreting Ctrl+C as SIGINT, it prints the raw escape sequence.

Fix

Disable the setting in VS Code:

1. Open Settings (Cmd + ,)
2. Search for enableKittyKeyboardProtocol
3. Uncheck Terminal > Integrated: Enable Kitty Keyboard Protocol

Or add this to your settings.json:
"terminal.integrated.enableKittyKeyboardProtocol": false

Alternatively, you can update fish shell to a version that supports the Kitty Keyboard Protocol if one is available.

And it's really fixed by disabling it 😆

this commit seems implemented that kitty keyboard protocol: fish-shell/fish-shell@8bf8b10

Edit: As those commands work in kitty + ghostty it must be a problem with vscode

cross linking: #294651

[amyspark]

Can this be reopened? I can confirm this issue is reproducible through Remote SSH against Fish 4.5.0.

VS Code version:

Versión: 1.110.0-insider
Confirmar: 243a432d167fe650b6afc83563bb704f9233c682
Fecha: 2026-02-19T05:13:10.261Z
Electron: 39.6.0
ElectronBuildId: 13330601
Chromium: 142.0.7444.265
Node.js: 22.22.0
V8: 14.2.231.22-electron.0
SO: Darwin arm64 24.6.0

[Arctyc]

Cannot repro, thus closing. Try using Developer: Toggle Keyboard Shortcuts Troubleshooting to debug

bug-no-repro.mov
no-repro2.mov

I can reproduce it on 1.110. How about we reopen?^[[99;5u^[[99;5u^[[99;5u^[[99;5u^[[99;5u^[[99;5u^[[99;5u^[[99;5u^[[99;5u

Additionally, it's worse if I switch to bash. Then backspace types u7 or something instead.

[anthonykim1]

This is very interesting. /cc @Tyriar
I couldn't repro on 3.7.1, but was able to after updating Fish to latest:

After updating fish to latest:

^C was fine when testing in fish outside of VS Code. Will need to investigate