diff --git a/AGENTS.md b/AGENTS.md
index c48e141..6142300 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -6,7 +6,7 @@ These are requirements, not preferences. Changing one needs the owner's agreemen
 
 - Never deploy unless the owner asks for it in the current turn. A finished change is reported undeployed; the owner deploys it, or asks you to. Never run `go install ./cmd/byre` or restart the service on your own initiative, not even to check that a change works.
 - `docs/operations.md` describes the layout, data, service and APIs; keep it current with every change.
-- Never add tests. byre has no test suite; check a change with `go vet ./...`, `go generate ./web` (which type-checks the UI) and, when `mac/` changed, `swift build --package-path mac`.
+- Never add tests. byre has no test suite; check a change with `go vet ./...`, `go generate ./web` (which type-checks the UI) and, when `mac/` changed, `mac/bundle.sh` (release only; debug builds are refused).
 - The web UI (`web/src/`) and the macOS app (`mac/Sources/Byre/`) are two clients of the same views. A change to what a client shows or does, such as Markdown rendering, goes into both in the same task; never leave one client behind.
 
 ## Deploying
diff --git a/docs/macos.md b/docs/macos.md
index 997dca2..fa7371e 100644
--- a/docs/macos.md
+++ b/docs/macos.md
@@ -18,7 +18,9 @@ The first version copies the web client: the same two equal panes, tabs, labels,
 - `UserNotifications` for notifications.
 - Third-party code: Apple's `swift-openapi-generator` (with `swift-openapi-runtime` and `swift-openapi-urlsession`) for the API types and client, and SwiftTerm for the terminal.
 
-The host has the Command Line Tools and no Xcode (`xcode-select --print-path` prints which), so the project is a Swift package under `mac/`, built with `swift build`, not an Xcode project. `mac/bundle.sh` builds the release configuration and assembles `mac/.build/byre.app` (the executable, `mac/Info.plist` with the fixed bundle identifier `run.fc.byre.mac`, the `web/fonts/` files and an `.icns` rendered from `web/favicon-tile.svg`) and signs it ad hoc; notification permission needs the bundle identifier. The app keeps its server origin in the `byre.server` default (`defaults read run.fc.byre.mac byre.server` prints it).
+The project is a Swift package under `mac/`, built with `swift build`, not an Xcode project. It builds with Xcode's toolchain: `xcode-select --print-path` must print `/Applications/Xcode.app/Contents/Developer`. With the Command Line Tools selected while Xcode is installed, Swift Build finds two toolchains for the Command Line Tools path and picks one at random on each run; the pick is part of the build request, so every change of pick rebuilds every target. `mac/bundle.sh` builds the release configuration and assembles `mac/.build/byre.app` (the executable, `mac/Info.plist` with the fixed bundle identifier `run.fc.byre.mac`, the `web/fonts/` files and an `.icns` rendered from `web/favicon-tile.svg`, cached as `mac/.build/byre.icns` until the SVG changes) and signs it ad hoc; notification permission needs the bundle identifier.
+
+Only the release configuration is built. A debug build stops at an `#error` in `ByreApp.swift`, and even a failed one leaves the next release build recompiling every target, since the two configurations share `mac/.build`. The generated API client is its own target, `ByreAPI`, so an edit to the app recompiles only the `Byre` target. SwiftPM builds release targets whole-module, so that is one compile of the whole `Byre` target, and a one-file change still costs that. The app keeps its server origin in the `byre.server` default (`defaults read run.fc.byre.mac byre.server` prints it).
 
 SwiftUI's own macros don't build here: the SDK declares `@State`, `@Entry`, `@Animatable` and the rest as macros implemented in the `SwiftUIMacros` plugin, which ships with Xcode and not with the Command Line Tools (`ls /Library/Developer/CommandLineTools/usr/lib/swift/host/plugins` lists the plugins there). `@State` is reached through its property-wrapper type instead, as `typealias ViewState = State` and `@ViewState var …`; other SwiftUI macros aren't used. `@Observable` and `@Bindable` (Observation's plugin, which the Command Line Tools have), `@Environment` and `@FocusState` work as usual.
 
@@ -28,7 +30,7 @@ Values the web client defines are generated into Swift, never copied by hand, so
 
 | Value | Source | Swift |
 | --- | --- | --- |
-| API types and client | `api/openapi.yaml` | Generated at build time by the `swift-openapi-generator` plugin (`mac/Sources/Byre/openapi-generator-config.yaml`, idiomatic naming: `display_name` is `displayName`) from the symlink `mac/Sources/Byre/openapi.yaml` to the spec. The output lands in `mac/.build/plugins/outputs/`, not in git |
+| API types and client | `api/openapi.yaml` | Generated at build time into the `ByreAPI` target by the `swift-openapi-generator` plugin (`mac/Sources/ByreAPI/openapi-generator-config.yaml`, public access, idiomatic naming: `display_name` is `displayName`) from the symlink `mac/Sources/ByreAPI/openapi.yaml` to the spec. App files that use it `import ByreAPI`. The output lands in `mac/.build/plugins/outputs/`, not in git |
 | Palette, light and dark | Custom properties at the top of `web/style.css` (`:root` and its `prefers-color-scheme: dark` block) | `go generate ./mac` (`mac/palette`) writes `Palette.swift`: one dynamic `Color` per hex property, `--accent-tint` as `Palette.accentTint`, resolving light or dark with the window's appearance. Properties that aren't a hex colour (`--task`, `--shadow`, `--font`) are left out. The file is committed, so `swift build` needs no Go; a property missing from either block fails the generator |
 | Font | `web/fonts/` | The build script copies the woff2 files into the bundle; the app loads each with `CTFontManagerCreateFontDescriptorsFromURL` (see "Gaps in SwiftUI") |
 | App icon | `web/favicon-tile.svg` | The build script renders it to an `.icns` with `rsvg-convert` and `iconutil` |
@@ -188,7 +190,7 @@ Platform differences the copy can't avoid, each with what the web client does an
 
 ## Building and checking
 
-`swift build --package-path mac` is the compile check for changes under `mac/`, alongside the checks `AGENTS.md` already names. No tests are added. Installing the app is a separate action from deploying the byre service.
+`mac/bundle.sh` is the compile check for changes under `mac/`, alongside the checks `AGENTS.md` already names. No tests are added. Installing the app is a separate action from deploying the byre service.
 
 ## Not in version one
 
diff --git a/mac/Package.swift b/mac/Package.swift
index c815d58..86a30d7 100644
--- a/mac/Package.swift
+++ b/mac/Package.swift
@@ -11,14 +11,21 @@ let package = Package(
         .package(url: "https://github.com/apple/swift-openapi-urlsession", from: "1.1.0"),
     ],
     targets: [
-        .executableTarget(
-            name: "Byre",
+        .target(
+            name: "ByreAPI",
             dependencies: [
-                .product(name: "SwiftTerm", package: "SwiftTerm"),
                 .product(name: "OpenAPIRuntime", package: "swift-openapi-runtime"),
-                .product(name: "OpenAPIURLSession", package: "swift-openapi-urlsession"),
             ],
             plugins: [.plugin(name: "OpenAPIGenerator", package: "swift-openapi-generator")]
         ),
+        .executableTarget(
+            name: "Byre",
+            dependencies: [
+                "ByreAPI",
+                .product(name: "SwiftTerm", package: "SwiftTerm"),
+                .product(name: "OpenAPIRuntime", package: "swift-openapi-runtime"),
+                .product(name: "OpenAPIURLSession", package: "swift-openapi-urlsession"),
+            ]
+        ),
     ]
 )
diff --git a/mac/Sources/Byre/API.swift b/mac/Sources/Byre/API.swift
index 9b0a2d1..421cdeb 100644
--- a/mac/Sources/Byre/API.swift
+++ b/mac/Sources/Byre/API.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import Foundation
 import HTTPTypes
 import OpenAPIRuntime
diff --git a/mac/Sources/Byre/ByreApp.swift b/mac/Sources/Byre/ByreApp.swift
index 6a18738..7984bc2 100644
--- a/mac/Sources/Byre/ByreApp.swift
+++ b/mac/Sources/Byre/ByreApp.swift
@@ -1,6 +1,10 @@
 import AppKit
 import SwiftUI
 
+#if DEBUG
+#error("debug builds are unsupported: build with mac/bundle.sh")
+#endif
+
 typealias ViewState = State
 
 @MainActor
diff --git a/mac/Sources/Byre/Changes.swift b/mac/Sources/Byre/Changes.swift
index 997be65..1b087cc 100644
--- a/mac/Sources/Byre/Changes.swift
+++ b/mac/Sources/Byre/Changes.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import SwiftUI
 
 typealias TaskChanges = Components.Schemas.TaskChanges
diff --git a/mac/Sources/Byre/Chat.swift b/mac/Sources/Byre/Chat.swift
index 2fe47b1..d39aba5 100644
--- a/mac/Sources/Byre/Chat.swift
+++ b/mac/Sources/Byre/Chat.swift
@@ -1,4 +1,5 @@
 import AppKit
+import ByreAPI
 import SwiftUI
 
 enum ChatKind: Equatable {
diff --git a/mac/Sources/Byre/Composer.swift b/mac/Sources/Byre/Composer.swift
index 2c136cb..1de4fff 100644
--- a/mac/Sources/Byre/Composer.swift
+++ b/mac/Sources/Byre/Composer.swift
@@ -1,4 +1,5 @@
 import AppKit
+import ByreAPI
 import OpenAPIRuntime
 import SwiftUI
 import UniformTypeIdentifiers
diff --git a/mac/Sources/Byre/Files.swift b/mac/Sources/Byre/Files.swift
index 910b894..bcca51e 100644
--- a/mac/Sources/Byre/Files.swift
+++ b/mac/Sources/Byre/Files.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import SwiftUI
 
 typealias DirListing = Components.Schemas.DirListing
diff --git a/mac/Sources/Byre/Format.swift b/mac/Sources/Byre/Format.swift
index 0ba0dba..fc16b3c 100644
--- a/mac/Sources/Byre/Format.swift
+++ b/mac/Sources/Byre/Format.swift
@@ -1,4 +1,5 @@
 import AppKit
+import ByreAPI
 import OpenAPIRuntime
 import SwiftUI
 
diff --git a/mac/Sources/Byre/Inbox.swift b/mac/Sources/Byre/Inbox.swift
index 1b48c9a..a16f176 100644
--- a/mac/Sources/Byre/Inbox.swift
+++ b/mac/Sources/Byre/Inbox.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import OpenAPIRuntime
 import SwiftUI
 
diff --git a/mac/Sources/Byre/MergeDialog.swift b/mac/Sources/Byre/MergeDialog.swift
index cb1cb38..c08589b 100644
--- a/mac/Sources/Byre/MergeDialog.swift
+++ b/mac/Sources/Byre/MergeDialog.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import SwiftUI
 
 typealias Participant = Components.Schemas.Participant
diff --git a/mac/Sources/Byre/PaneFocus.swift b/mac/Sources/Byre/PaneFocus.swift
index 7a19612..e3639af 100644
--- a/mac/Sources/Byre/PaneFocus.swift
+++ b/mac/Sources/Byre/PaneFocus.swift
@@ -1,4 +1,5 @@
 import AppKit
+import ByreAPI
 import SwiftUI
 
 @MainActor
diff --git a/mac/Sources/Byre/Panes.swift b/mac/Sources/Byre/Panes.swift
index bb882a6..57834a3 100644
--- a/mac/Sources/Byre/Panes.swift
+++ b/mac/Sources/Byre/Panes.swift
@@ -1,4 +1,5 @@
 import AppKit
+import ByreAPI
 import SwiftUI
 
 enum TabBadge {
diff --git a/mac/Sources/Byre/Project.swift b/mac/Sources/Byre/Project.swift
index 57279fa..eaef8f2 100644
--- a/mac/Sources/Byre/Project.swift
+++ b/mac/Sources/Byre/Project.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import SwiftUI
 
 typealias Todo = Components.Schemas.Todo
diff --git a/mac/Sources/Byre/Reviews.swift b/mac/Sources/Byre/Reviews.swift
index 6d00369..ee7a19b 100644
--- a/mac/Sources/Byre/Reviews.swift
+++ b/mac/Sources/Byre/Reviews.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import SwiftUI
 
 typealias FindingState = Components.Schemas.FindingState
diff --git a/mac/Sources/Byre/Settings.swift b/mac/Sources/Byre/Settings.swift
index 2969119..690a95d 100644
--- a/mac/Sources/Byre/Settings.swift
+++ b/mac/Sources/Byre/Settings.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import SwiftUI
 import UserNotifications
 
diff --git a/mac/Sources/Byre/Status.swift b/mac/Sources/Byre/Status.swift
index 69f8a1d..3ce9361 100644
--- a/mac/Sources/Byre/Status.swift
+++ b/mac/Sources/Byre/Status.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import SwiftUI
 
 typealias AgentProcess = Components.Schemas.AgentProcess
diff --git a/mac/Sources/Byre/Switcher.swift b/mac/Sources/Byre/Switcher.swift
index fd343b6..f2fff4d 100644
--- a/mac/Sources/Byre/Switcher.swift
+++ b/mac/Sources/Byre/Switcher.swift
@@ -1,4 +1,5 @@
 import AppKit
+import ByreAPI
 import SwiftUI
 
 typealias WorkflowSummary = Components.Schemas.WorkflowSummary
diff --git a/mac/Sources/Byre/Workflow.swift b/mac/Sources/Byre/Workflow.swift
index 4be5de8..934d8c8 100644
--- a/mac/Sources/Byre/Workflow.swift
+++ b/mac/Sources/Byre/Workflow.swift
@@ -1,3 +1,4 @@
+import ByreAPI
 import SwiftUI
 
 typealias WorkflowRun = Components.Schemas.WorkflowRun
diff --git a/mac/Sources/ByreAPI/ByreAPI.swift b/mac/Sources/ByreAPI/ByreAPI.swift
new file mode 100644
index 0000000..f823880
--- /dev/null
+++ b/mac/Sources/ByreAPI/ByreAPI.swift
@@ -0,0 +1 @@
+import OpenAPIRuntime
diff --git a/mac/Sources/Byre/openapi-generator-config.yaml b/mac/Sources/ByreAPI/openapi-generator-config.yaml
similarity index 69%
rename from mac/Sources/Byre/openapi-generator-config.yaml
rename to mac/Sources/ByreAPI/openapi-generator-config.yaml
index ee9d836..8e60f91 100644
--- a/mac/Sources/Byre/openapi-generator-config.yaml
+++ b/mac/Sources/ByreAPI/openapi-generator-config.yaml
@@ -1,5 +1,5 @@
 generate:
   - types
   - client
-accessModifier: internal
+accessModifier: public
 namingStrategy: idiomatic
diff --git a/mac/Sources/Byre/openapi.yaml b/mac/Sources/ByreAPI/openapi.yaml
similarity index 100%
rename from mac/Sources/Byre/openapi.yaml
rename to mac/Sources/ByreAPI/openapi.yaml
diff --git a/mac/bundle.sh b/mac/bundle.sh
index 69c27c5..6640b3e 100755
--- a/mac/bundle.sh
+++ b/mac/bundle.sh
@@ -4,20 +4,24 @@ mac=$(cd "$(dirname "$0")" && pwd)
 root=$(dirname "$mac")
 build=$mac/.build
 app=$build/byre.app
+svg=$root/web/favicon-tile.svg
+icns=$build/byre.icns
 swift build --package-path "$mac" --configuration release
-bin=$(swift build --package-path "$mac" --configuration release --show-bin-path)
+if [ ! "$icns" -nt "$svg" ]; then
+	iconset=$build/byre.iconset
+	rm -rf "$iconset"
+	mkdir -p "$iconset"
+	for size in 16 32 128 256 512; do
+		rsvg-convert --width $size --height $size --output "$iconset/icon_${size}x${size}.png" "$svg"
+		rsvg-convert --width $((size * 2)) --height $((size * 2)) --output "$iconset/icon_${size}x${size}@2x.png" "$svg"
+	done
+	iconutil --convert icns --output "$icns" "$iconset"
+fi
 rm -rf "$app"
 mkdir -p "$app/Contents/MacOS" "$app/Contents/Resources/fonts"
-cp "$bin/Byre" "$app/Contents/MacOS/Byre"
+cp "$build/release/Byre" "$app/Contents/MacOS/Byre"
 cp "$mac/Info.plist" "$app/Contents/Info.plist"
 cp "$root"/web/fonts/*.woff2 "$app/Contents/Resources/fonts/"
-iconset=$build/byre.iconset
-rm -rf "$iconset"
-mkdir -p "$iconset"
-for size in 16 32 128 256 512; do
-	rsvg-convert --width $size --height $size --output "$iconset/icon_${size}x${size}.png" "$root/web/favicon-tile.svg"
-	rsvg-convert --width $((size * 2)) --height $((size * 2)) --output "$iconset/icon_${size}x${size}@2x.png" "$root/web/favicon-tile.svg"
-done
-iconutil --convert icns --output "$app/Contents/Resources/byre.icns" "$iconset"
+cp "$icns" "$app/Contents/Resources/byre.icns"
 codesign --force --sign - "$app"
 echo "$app"