Windows: ctrl+s never reaches panes, only a release event is emitted

[0xMMA]

Is this a reproducible bug?

• I confirm this is a reproducible bug, not a feature request, idea, question, contribution proposal, or direction check.
• I reproduced this bug on the version and environment reported below using the exact steps provided.

Current behavior

ctrl+s never reaches a pane application on a native Windows client. Claude Code binds
ctrl+s to stashing the current prompt input; inside a Herdr pane the key does nothing.
The same Claude Code build in the same Windows Terminal, started directly from PowerShell
without Herdr, stashes the input as expected.

With HERDR_WINDOWS_INPUT_TRACE=1, two ctrl+s presses produce only release events and
no press event:

windows input trace: client input events events=[Key { code: Char('s'), modifiers: 2,
  kind: Release, repeat_count: 1, generated_text: None, source: WindowsConsole { record:
  WindowsKeyRecord { key_down: false, repeat_count: 1, virtual_key_code: 83,
  virtual_scan_code: 31, unicode: 19, control_key_state: 40 } } }]

Plain s in the same trace produces both a press and a release. ctrl+shift+s behaves
like ctrl+s. ctrl+g, ctrl+b, ctrl+j and unmodified keys are unaffected.

Expected behavior

ctrl+s reaches the pane application as a key press, like other ctrl+letter chords.

Reproduction

1. In Windows Terminal, run herdr.
2. In a pane, run claude, type a few characters into the prompt, press ctrl+s.
   Nothing happens; the input stays in the prompt.
3. Run claude directly in a PowerShell tab in the same terminal, type a few characters,
   press ctrl+s. The input is stashed.

Optional, to see it at the input layer: start a client with
$env:HERDR_WINDOWS_INPUT_TRACE="1"; herdr, press ctrl+s twice and ctrl+g once, then
compare the emitted events in herdr-client.log.

Impact

ctrl+s is a shortcut I use constantly to park a half-written prompt, change the model,
and restore the text. It is unusable in every Herdr pane on this machine, so I had to
rebind the action to alt+s in Claude Code.

Environment

• Herdr version: 0.9.0, client and server
• Update channel: stable
• Operating system: Windows 11 Pro N, OS build 10.0.26200
• Terminal: Windows Terminal 1.24.11911.0
• Shell: PowerShell 7
• Keyboard layout: US-International
• Relevant config: none, reproduces with default config

[akbash-bot]

Could you capture the raw console records for one Ctrl+S press? This will distinguish Windows withholding the press from Herdr dropping it during decoding.

1. In PowerShell outside Herdr, start the traced client:

$env:HERDR_WINDOWS_INPUT_TRACE="1"; herdr

2. In a second PowerShell tab outside Herdr, run:

$base = if ($env:XDG_CONFIG_HOME) { $env:XDG_CONFIG_HOME } else { $env:APPDATA }
Get-Content "$base\herdr\herdr-client.log" -Tail 0 -Wait | Select-String "windows input trace: (console key record|client input events)"

3. Return to the Claude prompt in Herdr, press Ctrl+S once, then plain s once. Return to the second tab and press Ctrl+C to stop watching.

Please paste just that captured output, including the console key record lines. The source log is herdr-client.log at the path above; the command only prints new matching lines and creates no extra file. Input traces can expose typed text, so avoid typing anything private during capture. After detaching the traced client, run Remove-Item Env:HERDR_WINDOWS_INPUT_TRACE in its PowerShell tab.

[0xMMA]

Captured as requested. One ctrl+s press, then one plain s press, in a pane running
Claude Code, with HERDR_WINDOWS_INPUT_TRACE=1.

Both keys emit only a release event; neither produces a press. The console key records
arrive as win32-input-mode byte sequences (virtual_key_code=0), which assemble to:

ESC [ 17;29;0;1;40;1_      CTRL   key-down
ESC [ 83;31;19;0;40;1_     S      key-up      (no key-down)
ESC [ 17;29;0;0;32;1_      CTRL   key-up
ESC [ 83;31;115;0;32;1_    s      key-up      (no key-down)

Raw lines, starting at the first byte of the first sequence:

2026-09-11T19:05:52.769896Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=27 control_key_state=0
2026-09-11T19:05:52.769945Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=91 control_key_state=0
2026-09-11T19:05:52.769953Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:52.769959Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=55 control_key_state=0
2026-09-11T19:05:52.769964Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:52.769969Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=50 control_key_state=0
2026-09-11T19:05:52.769975Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=57 control_key_state=0
2026-09-11T19:05:52.769984Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:52.769999Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=48 control_key_state=0
2026-09-11T19:05:52.770010Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:52.770017Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:52.770024Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:52.770031Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=52 control_key_state=0
2026-09-11T19:05:52.770038Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=48 control_key_state=0
2026-09-11T19:05:52.770044Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:52.770049Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:52.770052Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=95 control_key_state=0
2026-09-11T19:05:53.365228Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=27 control_key_state=0
2026-09-11T19:05:53.365256Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=91 control_key_state=0
2026-09-11T19:05:53.365268Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=56 control_key_state=0
2026-09-11T19:05:53.365272Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=51 control_key_state=0
2026-09-11T19:05:53.365278Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.365287Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=51 control_key_state=0
2026-09-11T19:05:53.365291Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:53.365295Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.365298Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:53.365301Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=57 control_key_state=0
2026-09-11T19:05:53.365305Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.365314Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=48 control_key_state=0
2026-09-11T19:05:53.365319Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.365321Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=52 control_key_state=0
2026-09-11T19:05:53.365324Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=48 control_key_state=0
2026-09-11T19:05:53.365326Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.365329Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:53.365331Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=95 control_key_state=0
2026-09-11T19:05:53.365341Z  INFO herdr::client::input::windows_vti: windows input trace: client input events events=[Key { code: Char('s'), modifiers: 2, kind: Release, repeat_count: 1, generated_text: None, source: WindowsConsole { record: WindowsKeyRecord { key_down: false, repeat_count: 1, virtual_key_code: 83, virtual_scan_code: 31, unicode: 19, control_key_state: 40 } } }]
2026-09-11T19:05:53.443863Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=27 control_key_state=0
2026-09-11T19:05:53.443898Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=91 control_key_state=0
2026-09-11T19:05:53.443903Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:53.443907Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=55 control_key_state=0
2026-09-11T19:05:53.443911Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.443915Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=50 control_key_state=0
2026-09-11T19:05:53.443918Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=57 control_key_state=0
2026-09-11T19:05:53.443922Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.443925Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=48 control_key_state=0
2026-09-11T19:05:53.443929Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.443932Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=48 control_key_state=0
2026-09-11T19:05:53.443941Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.443948Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=51 control_key_state=0
2026-09-11T19:05:53.443951Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=50 control_key_state=0
2026-09-11T19:05:53.443955Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:53.443958Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:53.443962Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=95 control_key_state=0
2026-09-11T19:05:54.510270Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=27 control_key_state=0
2026-09-11T19:05:54.510302Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=91 control_key_state=0
2026-09-11T19:05:54.510307Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=56 control_key_state=0
2026-09-11T19:05:54.510311Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=51 control_key_state=0
2026-09-11T19:05:54.510314Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:54.510318Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=51 control_key_state=0
2026-09-11T19:05:54.510321Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:54.510325Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:54.510329Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:54.510332Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:54.510335Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=53 control_key_state=0
2026-09-11T19:05:54.510339Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:54.510342Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=48 control_key_state=0
2026-09-11T19:05:54.510351Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:54.510358Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=51 control_key_state=0
2026-09-11T19:05:54.510361Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=50 control_key_state=0
2026-09-11T19:05:54.510363Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=59 control_key_state=0
2026-09-11T19:05:54.510365Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=49 control_key_state=0
2026-09-11T19:05:54.510368Z  INFO herdr::client::input::windows_vti: windows input trace: console key record key_down=true repeat_count=1 virtual_key_code=0 virtual_scan_code=0 unicode=95 control_key_state=0
2026-09-11T19:05:54.510377Z  INFO herdr::client::input::windows_vti: windows input trace: client input events events=[Key { code: Char('s'), modifiers: 0, kind: Release, repeat_count: 1, generated_text: None, source: WindowsConsole { record: WindowsKeyRecord { key_down: false, repeat_count: 1, virtual_key_code: 83, virtual_scan_code: 31, unicode: 115, control_key_state: 32 } } }]

Console input mode in that tab was 0x9F (PROCESSED|LINE|ECHO set).

One more data point: I cannot reproduce this on a second Windows machine. I will follow up
with its Windows build and Windows Terminal version.