Wispr Flow + MX Ergo Push-to-Talk — Handoff to Claude Desktop

Last updated: 2026-04-29 (mid-session)

Goal

Eric wants to press and hold the top front button (▲) on his MX Ergo trackball to push-to-talk in Wispr Flow. Release = stop dictating.

Current state of his Mac

What's done

Karabiner-Elements v15.9.0 is installed at /Applications/Karabiner-Elements.app
Karabiner config file at ~/.config/karabiner/karabiner.json already has the rule we need: json { "description": "MX Ergo top front button (▲) → Cmd+\\ for Wispr Flow push-to-talk", "manipulators": [ { "from": { "pointing_button": "button5" }, "to": [ { "key_code": "backslash", "modifiers": ["left_command"] } ], "type": "basic" } ] } (Confirmed via Karabiner-EventViewer that the ▲ button is button5 — Eric pressed it, EventViewer showed pointing_button: button5 for both up and down events.)
Wispr Flow has ⌘\ (Command + Backslash) added under Push to talk in Settings → Shortcuts. The original ⌘D is also still there (kept as a keyboard fallback).
Logi Options+ has been killed and its launchd unloaded (launchctl unload /Library/LaunchAgents/com.logi.optionsplus.plist) so it doesn't intercept the button. It will respawn on next login unless we leave it unloaded.

What's broken / blocking

Karabiner's karabiner_grabber daemon is NOT running. Confirmed by:

pgrep -lf "karabiner"
# returns only: karabiner_session_monitor, karabiner_console_user_server
# MISSING: karabiner_grabber, karabiner_observer

And:

sudo launchctl list | grep -i karabiner
# returns nothing
ls /Library/LaunchDaemons/ | grep -i karabiner
# returns nothing

This means Karabiner's driver/system extension was never approved. The config rule exists but nothing is intercepting events. (The pre-existing Chrome middle-click rule has likely been silently broken too.)

What Claude Desktop needs to do

1. Activate Karabiner's driver

Karabiner-Elements 14+ uses a DriverKit system extension. To activate: - Open Karabiner-Elements (/Applications/Karabiner-Elements.app) — should already be open in front - There will be a banner at the top of the main window saying something like "Karabiner-DriverKit-VirtualHIDDevice is not activated" with an Install or Enable button — click it - macOS will show a "System Extension Blocked" notification — that's normal - This redirects you to System Settings → Privacy & Security - Scroll to the bottom — there will be a section saying "System software from application 'Karabiner-Elements' was blocked from loading" with an Allow button — click it - Authenticate with password / Touch ID

2. Grant Input Monitoring permission

System Settings → Privacy & Security → Input Monitoring: - Add Karabiner-Elements, karabiner_grabber, karabiner_observer, karabiner_console_user_server if any are missing - Toggle each one ON

3. Grant Accessibility permission

System Settings → Privacy & Security → Accessibility: - Same as above — add and enable each Karabiner binary

4. Reboot

DriverKit extensions sometimes need a reboot to fully load. Don't skip this.

5. Verify after reboot

pgrep -lf "karabiner_grabber"
# Should show: /Library/Application Support/org.pqrs/Karabiner-Elements/bin/karabiner_grabber

If karabiner_grabber is running, the rule is live.

6. Test

Click into a text field (Notes, browser, anywhere)
Press and HOLD the ▲ button on the MX Ergo
Wispr Flow should activate (overlay/indicator appears)
Speak
Release the button
Dictated text appears in the field

7. Re-enable Logi Options+ (optional cleanup)

Once the mouse trigger works, restart Logi Options+ so other mouse buttons keep working:

launchctl load /Library/LaunchAgents/com.logi.optionsplus.plist
open -a "logioptionsplus"

IMPORTANT: In Logi Options+, the top front button (▲) must be set to "Forward" (the default action) — NOT "Keyboard shortcut." If it's set to a keystroke, Logi will intercept the button before Karabiner can see it. Leave it as Forward and Karabiner does the rest.

Why we ended up here

Logi Options+ has a documented bug firing modifier-key combos (like ⌃⌥\ or ⌘\) on certain Logitech mice including the MX Ergo. Single keystrokes work; multi-key combos don't. This is why we couldn't just use Logi Options+ alone.
Wispr Flow's shortcut field is keyboard-only — it won't let you record a mouse button directly, even though its docs say Mouse 4–10 are supported. So we can't bypass the keystroke layer.
Karabiner is the canonical solution for this use case (confirmed by John Nunemaker on X who set up the same thing on an MX Master 3 with Wispr Flow). Just needs a working install.