Tool #88 locks your keyboard.

Yesterday's post about the 87-tool panel ended with a promise: "If a tool you reach for is missing, say so. It's a ten-line diff now."

Today someone said: my keyboard is filthy, and I can't clean it while it's typing.

Which — yes. Everyone knows this problem and nobody talks about it. You grab a cloth, you swipe, and suddenly you've muted a call, sent half a Slack message, and opened three copies of Mission Control. The workarounds are all bad: shutting down, cleaning the keyboard of a lit-up laptop while it drips, or hovering one finger over the power button like it's a detonator.

So: Clean keyboard, flagship of the new Desk & Character section. Click Lock keyboard, and every key on the machine goes quiet — letters, modifiers, media keys, all of it. Wipe with abandon. Click the very large Unlock button when you're done. That's the whole tool, and it's exactly the tool you never knew existed until the first time you need it.

The part that had to be engineered

I'll be honest about the promise: this one was not a ten-line diff. The 87 catalog tools are data — a command, an input, a timeout. Locking a keyboard is not a command; it's a CGEventTap: a hook at the lowest level macOS allows, which sees every keystroke on the system and — in our case — swallows them. It's the same mechanism screen readers and keyboard remappers use, and macOS rightly gates it behind the Accessibility permission. The tool asks once, explains why in plain words, and deep-links the exact Settings pane. No permission, no lock — and it tells you so instead of failing silently.

A tool whose entire job is disabling your keyboard has one failure mode that matters: staying locked. Three things guard against it:

• The pointer is never touched. Mouse and trackpad stay fully alive; Unlock is always one generous click away — sized for a hand that's holding a cloth.
• A failsafe always runs. If the unlock click never comes, the lock tears itself down after three minutes, no matter what. Wander off mid-clean; the keyboard comes back on its own.
• If macOS pulls the plug, we don't fight it. The system can disable an event tap on its own; we treat that as an unlock, not something to re-arm against the OS.

That's the difference between a fun hack and a tool you can trust: the hack is the event tap; the engineering is the three ways out.

Why a localhost app has a keyboard tool

Fair question. The Tools panel long ago stopped pretending to be only about ports — it's the drawer of things a developer reaches for while already in the menu bar: kill a port, prune Docker, check what's on 3000. The keyboard you're cleaning is the same keyboard those commands come from. And the honest answer is also simpler: a user asked, it's genuinely useful, and it fit the safety rules — no sudo, one honest permission, labelled exactly like what it does.

88 tools now. The offer from yesterday stands.