The Floor Under the Seams

"Two seams decide what varies inside the app. A third decides what the app no longer writes alone."

The Seam This Track Did Not Name

Lesson 1 of this track counted two abstractions in the pipeline — the STT engine and the cleanup brain — and said everything else stays concrete. Inside Firekeeper that is still how the dictation path reads. But since the quest was written, a large part of what Firekeeper runs no longer lives in Firekeeper at all. It lives in cwkSiblingKit, the family's shared plumbing, and arrives two ways. That is a third kind of seam: not between alternatives inside one app, but between one app and the dozens of siblings that solve the same problems.

Two Ways the Kit Arrives

1. Linked as a package (Package.swift -> ../cwkSiblingKit/CwkKit)
   CwkKitCore       PippaDoor (one owner of the Pippa session), hardened HTTPS,
                    the Keychain store that tells LOCKED from MISSING
   CwkKitMac        the hotkey vocabulary: every key that has a name
   CwkKitSpeech     AudioTap: the audio tap block, built where no actor is inferred
   CwkKitVoice      the voice loop's parts: listener, mic owner, heard position, units
   CwkKitMedia      the streaming speech player
   CwkKitBiometric  Touch ID in front of a saved secret
   CwkKitTesting    the drift check the self-test runs

2. Vendored as generated copies (header: GENERATED FROM cwkSiblingKit ... DO NOT EDIT HERE)
   KitBrainControl.swift, KitPinAuth.swift, KitFamilyHome.swift, KitBrainStatusChip.swift
   Resources/UtilityWorker/*   (the Python utility worker)
   -> build-app.sh runs the kit's drift check and HARD_FAILs on a hand-edited copy

A linked product is one source of truth by construction. A vendored copy is a deliberate duplicate — needed where a target cannot take the package, or where a Python worker has to ship inside the app bundle — so it carries its origin in a header and a gate that refuses any drift. Firekeeper has no pytest or vitest suite for the family's checker to hook into, so its build script is where the drift check runs; it skips only on a Mac that does not have the kit repo at all.

Two Questions, Two Places

Moving code into a kit does not mean moving every decision with it. The hotkey case shows the line. Firekeeper's recorder once accepted any key carrying a modifier, while its name table covered neither Help, F13–F20 nor the keypad — so ⌘⌥F13 recorded, registered and worked, and Settings showed it as "⌘⌥key 105". The fix split one question into two. Which keys have names at all is a family fact, so naming moved to the kit: HotkeyKey can only be built from the complete table, and there is no numeric fallback left. Which keys this app wants is a product decision, so acceptance stayed in Firekeeper's own HotkeyValidation — Caps Lock is refused there, because hold-to-talk on a latching key is an open microphone.

What the Kit Bought

The kit is how fixes found in one app reach another. Firekeeper's clipboard restore saved only plain text; the family survey looking for duplicated code found that every other app already snapshotted all items, and Firekeeper took that shape. Its Swift 6 audio-tap crash was one the health app had already hit; the kit already shipped AudioTap.block(into:) for it, and the sweep that broke Firekeeper had simply not used it. One shared door to cwkPippa replaced a header pasted into three request builders and a retry that existed in one path and not in two others.