diff --git a/Sources/TVAnarchy/DevicesView.swift b/Sources/TVAnarchy/DevicesView.swift
new file mode 100644
index 0000000..7aa5e76
--- /dev/null
+++ b/Sources/TVAnarchy/DevicesView.swift
@@ -0,0 +1,354 @@
+import SwiftUI
+import TVAnarchyCore
+import AppKit
+
+/// Devices tab: the fleet registry. Left, the devices (black/apricot/plum/phone);
+/// right, the selected device's class/reachability, the combo of services it runs,
+/// and any duties assigned to it. Playback services keep the live, feature-detected
+/// tools; fleet services (transmission/compute/sink) surface their role. The
+/// duty-assignment engine is not here — duties are read, not computed.
+struct DevicesView: View {
+    @Bindable var fleet: FleetController
+    @Bindable var player: PlayerController
+    @State private var selectedID: String?
+
+    private var selected: Device? { fleet.device(selectedID ?? "") }
+
+    var body: some View {
+        HStack(spacing: 0) {
+            deviceList.frame(width: 250)
+            Divider()
+            detailPane.frame(maxWidth: .infinity, maxHeight: .infinity)
+        }
+        .onAppear { if selected == nil { selectedID = fleet.devices.first?.id } }
+    }
+
+    // MARK: Master list
+
+    private var deviceList: some View {
+        VStack(spacing: 0) {
+            HStack {
+                Text("Devices").font(.title2).bold()
+                Spacer()
+                Menu {
+                    Button("Reload") { fleet.reload() }
+                    Button("Reveal fleet.json") {
+                        NSWorkspace.shared.activateFileViewerSelecting([FleetConfig.configURL()])
+                    }
+                    Divider()
+                    Button("Reset to home fleet", role: .destructive) {
+                        fleet.resetToSeed(); selectedID = fleet.devices.first?.id
+                    }
+                } label: { Image(systemName: "ellipsis.circle") }
+                    .menuStyle(.borderlessButton).fixedSize()
+            }
+            .padding(.horizontal, 16).padding(.vertical, 12)
+
+            List(fleet.devices, selection: $selectedID) { d in
+                deviceRow(d).tag(d.id)
+            }
+        }
+    }
+
+    private func deviceRow(_ d: Device) -> some View {
+        HStack(spacing: 10) {
+            Image(systemName: d.deviceClass.icon)
+                .foregroundStyle(.secondary).frame(width: 18)
+            VStack(alignment: .leading, spacing: 2) {
+                HStack(spacing: 5) {
+                    Text(d.name).font(.headline)
+                    if hasActivePlayback(d) {
+                        Text("active").font(.caption2)
+                            .padding(.horizontal, 5).padding(.vertical, 1)
+                            .background(.tint.opacity(0.2), in: Capsule())
+                    }
+                }
+                HStack(spacing: 5) {
+                    Text(d.deviceClass.label).font(.caption).foregroundStyle(.secondary)
+                    ForEach(d.services) { s in
+                        Image(systemName: s.kind.icon).font(.caption2).foregroundStyle(.tertiary)
+                    }
+                    if !d.duties.isEmpty {
+                        Text("\(d.duties.count) ⚑").font(.caption2).foregroundStyle(.tertiary)
+                    }
+                }
+            }
+            Spacer()
+        }
+        .padding(.vertical, 2)
+    }
+
+    private func hasActivePlayback(_ d: Device) -> Bool {
+        d.playbackServices.contains { ($0.playbackHostID ?? $0.id) == player.activeID }
+    }
+
+    // MARK: Detail
+
+    @ViewBuilder private var detailPane: some View {
+        if let d = selected {
+            DeviceDetailView(fleet: fleet, player: player, deviceID: d.id).id(d.id)
+        } else {
+            VStack(spacing: 8) {
+                Image(systemName: "square.stack.3d.up").font(.largeTitle).foregroundStyle(.tertiary)
+                Text("Select a device").foregroundStyle(.secondary)
+            }
+            .frame(maxWidth: .infinity, maxHeight: .infinity)
+        }
+    }
+}
+
+/// Per-device detail: identity/class/reachability (editable), the services it runs
+/// (each a card — playback cards carry live tools), and assigned duties (read-only).
+struct DeviceDetailView: View {
+    @Bindable var fleet: FleetController
+    @Bindable var player: PlayerController
+    let deviceID: String
+
+    private var device: Device? { fleet.device(deviceID) }
+
+    var body: some View {
+        ScrollView {
+            if let d = device {
+                VStack(alignment: .leading, spacing: 26) {
+                    header(d)
+                    deviceSection(d)
+                    servicesSection(d)
+                    dutiesSection(d)
+                }
+                .padding(28).frame(maxWidth: .infinity, alignment: .leading)
+            }
+        }
+    }
+
+    private func header(_ d: Device) -> some View {
+        HStack(spacing: 12) {
+            Image(systemName: d.deviceClass.icon).font(.title).foregroundStyle(.tint)
+            VStack(alignment: .leading, spacing: 2) {
+                Text(d.name).font(.title).bold()
+                Text("\(d.deviceClass.label) · \(d.reachable.label)")
+                    .font(.callout).foregroundStyle(.secondary)
+            }
+            Spacer()
+            Button("Delete", role: .destructive) { fleet.deleteDevice(d.id) }
+                .disabled(fleet.devices.count <= 1)
+        }
+    }
+
+    // MARK: Device attributes (editable, write-through to fleet.json)
+
+    private func deviceSection(_ d: Device) -> some View {
+        sectionBox("Device") {
+            Picker("Class", selection: bind(d, \.deviceClass)) {
+                ForEach(DeviceClass.allCases) { Text($0.label).tag($0) }
+            }
+            Picker("Reachable", selection: bind(d, \.reachable)) {
+                ForEach(Reachability.allCases) { Text($0.label).tag($0) }
+            }
+            Toggle("Always on", isOn: bind(d, \.alwaysOn))
+            Toggle("On home IP", isOn: bind(d, \.onHomeIp))
+                .help("Public-swarm traffic over a home IP exposes the home connection.")
+        }
+    }
+
+    // MARK: Services (the combo this device runs)
+
+    private func servicesSection(_ d: Device) -> some View {
+        sectionBox("Services") {
+            ForEach(d.services) { s in
+                ServiceCard(service: s, player: player,
+                            onRemove: { fleet.removeService(s.id, from: d.id) },
+                            canRemove: d.services.count > 1)
+                if s.id != d.services.last?.id { Divider() }
+            }
+        }
+    }
+
+    // MARK: Duties (read-only — assigned by the governor/fleet engine)
+
+    private func dutiesSection(_ d: Device) -> some View {
+        sectionBox("Duties") {
+            if d.duties.isEmpty {
+                Text(d.deviceClass == .consumer
+                     ? "Consumer — never receives a duty."
+                     : "No duties assigned.")
+                    .font(.callout).foregroundStyle(.secondary)
+            } else {
+                HStack(spacing: 8) {
+                    ForEach(d.duties) { duty in
+                        Text(duty.label).font(.caption)
+                            .padding(.horizontal, 8).padding(.vertical, 3)
+                            .background(.tint.opacity(0.15), in: Capsule())
+                    }
+                }
+            }
+            Text("Assigned deterministically by the governor on registry change — read-only here.")
+                .font(.caption).foregroundStyle(.tertiary)
+        }
+    }
+
+    // MARK: write-through binding helper
+
+    private func bind<V>(_ d: Device, _ key: WritableKeyPath<Device, V>) -> Binding<V> {
+        Binding(
+            get: { fleet.device(d.id)?[keyPath: key] ?? d[keyPath: key] },
+            set: { newValue in
+                guard var cur = fleet.device(d.id) else { return }
+                cur[keyPath: key] = newValue
+                fleet.update(cur)
+            })
+    }
+
+    private func sectionBox<C: View>(_ title: String, @ViewBuilder _ content: () -> C) -> some View {
+        VStack(alignment: .leading, spacing: 12) {
+            Text(title).font(.headline)
+            content()
+        }
+    }
+}
+
+/// One service row. Playback services resolve their live `PlayerTarget` and expose
+/// the feature-detected tools (Stop / host load / releases / fullscreen / clear);
+/// fleet services show their role. A service with no live target shows that plainly.
+struct ServiceCard: View {
+    let service: Service
+    @Bindable var player: PlayerController
+    let onRemove: () -> Void
+    let canRemove: Bool
+
+    @State private var stats: HostStats?
+    @State private var releases: [Release] = []
+
+    private var hostID: String { service.playbackHostID ?? service.id }
+    private var target: (any PlayerTarget)? {
+        service.kind.isPlayback ? player.target(hostID) : nil
+    }
+    private var isActive: Bool { service.kind.isPlayback && hostID == player.activeID }
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            HStack(spacing: 8) {
+                Image(systemName: service.kind.icon).foregroundStyle(.secondary).frame(width: 18)
+                VStack(alignment: .leading, spacing: 1) {
+                    Text(service.kind.label).font(.headline)
+                    if let d = service.detail {
+                        Text(d).font(.caption.monospaced()).foregroundStyle(.secondary)
+                    }
+                }
+                if isActive {
+                    Text("active").font(.caption2).padding(.horizontal, 5).padding(.vertical, 1)
+                        .background(.tint.opacity(0.2), in: Capsule()).foregroundStyle(.tint)
+                }
+                Spacer()
+                if service.kind.isPlayback {
+                    Circle().fill(dotColor).frame(width: 9, height: 9)
+                }
+                if canRemove {
+                    Button { onRemove() } label: { Image(systemName: "minus.circle") }
+                        .buttonStyle(.borderless).foregroundStyle(.secondary)
+                        .help("Remove service")
+                }
+            }
+
+            if service.kind.isPlayback {
+                playbackTools
+            } else {
+                Text(roleNote).font(.callout).foregroundStyle(.secondary)
+            }
+        }
+        .padding(.vertical, 4)
+        .task(id: service.id) { await loadTools() }
+    }
+
+    // MARK: playback tools (feature-detected against the live target)
+
+    @ViewBuilder private var playbackTools: some View {
+        let t = target
+        if t == nil {
+            Text("No live connection — host unreachable or not configured.")
+                .font(.callout).foregroundStyle(.secondary)
+        } else {
+            HStack(spacing: 10) {
+                Button("Make active") { player.setActive(hostID) }.disabled(isActive)
+                Button(role: .destructive) {
+                    player.runTool(on: hostID) { await $0.stop() }
+                } label: { Label("Stop", systemImage: "stop.fill") }
+                if t is FullscreenControllable {
+                    Button {
+                        player.runTool(on: hostID) { await ($0 as? FullscreenControllable)?.toggleFullscreen() }
+                    } label: { Label("Fullscreen", systemImage: "arrow.up.left.and.arrow.down.right") }
+                }
+                if t is PlaylistClearable {
+                    Button {
+                        player.runTool(on: hostID) { await ($0 as? PlaylistClearable)?.clearPlaylist() }
+                    } label: { Label("Clear", systemImage: "trash") }
+                }
+            }
+            .buttonStyle(.bordered).controlSize(.small)
+
+            if t is HostStatsProvider { statsRow }
+            if t is QualitySwitchable { releasesRow }
+        }
+    }
+
+    private var statsRow: some View {
+        HStack(spacing: 8) {
+            Image(systemName: "gauge.with.dots.needle.50percent").foregroundStyle(.secondary)
+            if let s = stats {
+                Text("load \(fmt(s.load1)) · \(s.cores) cores" +
+                     (s.mpv_cpu.map { " · decode \(fmt($0))%" } ?? ""))
+                    .font(.callout.monospaced()).foregroundStyle(.secondary)
+            } else {
+                Text("no load data").font(.callout).foregroundStyle(.secondary)
+            }
+            Button { Task { stats = await player.deviceStats(hostID) } } label: {
+                Image(systemName: "arrow.clockwise")
+            }.buttonStyle(.borderless).help("Refresh")
+        }
+    }
+
+    @ViewBuilder private var releasesRow: some View {
+        if releases.isEmpty {
+            HStack(spacing: 6) {
+                Image(systemName: "rectangle.stack").foregroundStyle(.secondary)
+                Text("no alternate releases").font(.callout).foregroundStyle(.secondary)
+                Button { Task { releases = await player.deviceReleases(hostID) } } label: {
+                    Image(systemName: "arrow.clockwise")
+                }.buttonStyle(.borderless).help("Refresh")
+            }
+        } else {
+            VStack(alignment: .leading, spacing: 4) {
+                ForEach(releases) { r in
+                    HStack {
+                        Text(r.label) + Text(r.current ? "  (current)" : "").foregroundColor(.secondary)
+                        Spacer()
+                        Button("Switch") {
+                            player.runTool(on: hostID) { await ($0 as? QualitySwitchable)?.switchRelease(r.id) }
+                        }.disabled(r.current).controlSize(.small)
+                    }
+                }
+            }
+        }
+    }
+
+    private var roleNote: String {
+        switch service.kind {
+        case .transmission: "Torrent client — downloads and seeds. Manage transfers in the Downloads tab."
+        case .compute: "Offload target for GPU/CPU-heavy work (MLX title refining, ffmpeg, recommendations)."
+        case .sink: "Pure consumer — receives playback, never assigned a fleet duty."
+        default: ""
+        }
+    }
+
+    private func loadTools() async {
+        guard service.kind.isPlayback else { return }
+        stats = await player.deviceStats(hostID)
+        releases = await player.deviceReleases(hostID)
+    }
+
+    private var dotColor: Color {
+        switch player.snapshot(hostID).state {
+        case .connected: .green; case .checking: .gray; case .unreachable: .orange
+        }
+    }
+    private func fmt(_ d: Double) -> String { String(format: "%.2f", d) }
+}
diff --git a/Sources/TVAnarchy/HostsView.swift b/Sources/TVAnarchy/HostsView.swift
deleted file mode 100644
index 9f13528..0000000
--- a/Sources/TVAnarchy/HostsView.swift
+++ /dev/null
@@ -1,91 +0,0 @@
-import SwiftUI
-import TVAnarchyCore
-import AppKit
-
-/// Full host configuration: live connection state per host, plus add/edit/delete
-/// and "make active". Persists to hosts.json via the controller and reloads.
-struct HostsView: View {
-    @Bindable var controller: PlayerController
-    @State private var editing: HostConfig?      // edit sheet (existing host)
-    @State private var adding = false            // add sheet
-    @State private var confirmReset = false
-
-    private var hosts: [HostConfig] { controller.editableHosts }
-
-    var body: some View {
-        VStack(alignment: .leading, spacing: 16) {
-            HStack {
-                Text("Hosts").font(.title2).bold()
-                Spacer()
-                Button { adding = true } label: { Label("Add Host", systemImage: "plus") }
-            }
-
-            List(hosts) { h in
-                let snap = controller.snapshot(h.id)
-                HStack(spacing: 12) {
-                    Circle().fill(color(snap.state)).frame(width: 10)
-                    VStack(alignment: .leading, spacing: 2) {
-                        HStack(spacing: 6) {
-                            Text(h.name).font(.headline)
-                            if h.id == controller.activeID {
-                                Text("active").font(.caption2).padding(.horizontal, 5).padding(.vertical, 1)
-                                    .background(.tint.opacity(0.2), in: Capsule())
-                            }
-                        }
-                        Text("\(h.kind.label) · \(detail(h))")
-                            .font(.caption).foregroundStyle(.secondary)
-                    }
-                    Spacer()
-                    Text(stateLabel(snap.state)).font(.caption).foregroundStyle(color(snap.state))
-                    Menu {
-                        Button("Make active") { controller.setActive(h.id) }.disabled(h.id == controller.activeID)
-                        Button("Edit…") { editing = h }
-                        Button("Delete", role: .destructive) { controller.deleteHost(h.id) }
-                            .disabled(hosts.count <= 1)
-                    } label: { Image(systemName: "ellipsis.circle") }
-                        .menuStyle(.borderlessButton).fixedSize()
-                }
-                .padding(.vertical, 4)
-            }
-
-            HStack {
-                Button("Reload config") { controller.reload() }
-                Button("Reset to defaults") { confirmReset = true }
-                Button("Reveal hosts.json") {
-                    NSWorkspace.shared.activateFileViewerSelecting([HostsConfig.configURL()])
-                }
-                Spacer()
-                Text(HostsConfig.configURL().path)
-                    .font(.caption.monospaced()).foregroundStyle(.tertiary)
-            }
-        }
-        .padding(24)
-        .sheet(isPresented: $adding) {
-            HostEditView(existing: nil) { controller.upsertHost($0) }
-        }
-        .sheet(item: $editing) { h in
-            HostEditView(existing: h) { controller.upsertHost($0) }
-        }
-        .confirmationDialog("Reset hosts to the default plum VLC + black mpv set?",
-                            isPresented: $confirmReset, titleVisibility: .visible) {
-            Button("Reset", role: .destructive) { controller.resetHostsToDefault() }
-            Button("Cancel", role: .cancel) {}
-        }
-    }
-
-    private func detail(_ h: HostConfig) -> String {
-        switch h.kind {
-        case .vlc: h.vlc.map { "\($0.host):\($0.port)" } ?? "—"
-        case .mpvIPC: (h.mpv?.endpoints ?? []).joined(separator: ", ")
-        case .blacktv: (h.ssh?.endpoints ?? []).joined(separator: ", ")
-        case .quicktime: "local"
-        }
-    }
-
-    private func color(_ s: ConnectionState) -> Color {
-        switch s { case .connected: .green; case .checking: .gray; case .unreachable: .orange }
-    }
-    private func stateLabel(_ s: ConnectionState) -> String {
-        switch s { case .connected: "Connected"; case .checking: "Checking…"; case .unreachable: "Unreachable" }
-    }
-}
diff --git a/Sources/TVAnarchy/RootView.swift b/Sources/TVAnarchy/RootView.swift
index 026fb3e..bbe3fcd 100644
--- a/Sources/TVAnarchy/RootView.swift
+++ b/Sources/TVAnarchy/RootView.swift
@@ -9,7 +9,7 @@ struct RootView: View {
         case search = "Search"
         case downloads = "Downloads"
         case metadata = "Metadata"
-        case hosts = "Hosts"
+        case devices = "Devices"
         case logs = "Logs"
         case setup = "Setup"
         var id: String { rawValue }
@@ -21,7 +21,7 @@ struct RootView: View {
             case .search: return "magnifyingglass"
             case .downloads: return "arrow.down.circle.fill"
             case .metadata: return "wand.and.stars"
-            case .hosts: return "server.rack"
+            case .devices: return "tv"
             case .logs: return "list.bullet.rectangle"
             case .setup: return "gearshape.fill"
             }
@@ -35,6 +35,7 @@ struct RootView: View {
     @State private var search: SearchController
     @State private var playlist: PlaylistController
     @State private var log = LogController()
+    @State private var fleet = FleetController()
     @State private var selection: Section = .home
     @State private var showQueue = false
 
@@ -91,8 +92,8 @@ struct RootView: View {
                 DownloadsView(downloads: downloads, player: controller)
             case .metadata:
                 MetadataView(metadata: metadata)
-            case .hosts:
-                HostsView(controller: controller)
+            case .devices:
+                DevicesView(fleet: fleet, player: controller)
             case .logs:
                 LogView(log: log)
             case .setup:
diff --git a/Sources/TVAnarchyCore/PlayerController.swift b/Sources/TVAnarchyCore/PlayerController.swift
index 72e2b95..6fd05db 100644
--- a/Sources/TVAnarchyCore/PlayerController.swift
+++ b/Sources/TVAnarchyCore/PlayerController.swift
@@ -242,6 +242,41 @@ public final class PlayerController {
     /// Surface a transient note to the user (e.g. why a click did nothing).
     public func note(_ message: String?) { actionMessage = message }
 
+    // MARK: Device tools (act on a specific configured target, not the active one)
+
+    /// Look up a configured target by id — for the Devices detail pane, whose
+    /// selection is independent of the playback-active target.
+    public func target(_ id: String) -> (any PlayerTarget)? { targets.first { $0.id == id } }
+
+    /// Poll one target and apply its snapshot — refresh a device that isn't active
+    /// (the active one goes through `refreshActive`/the tick loop).
+    public func refresh(_ id: String) async {
+        guard let t = target(id), !polling else { return }
+        polling = true
+        defer { polling = false }
+        apply(await t.poll(), to: id)
+    }
+
+    /// Run a tool against a specific configured device (which may not be the active
+    /// playback target), then refresh just that device's snapshot.
+    public func runTool(on id: String, _ op: @escaping (any PlayerTarget) async -> Void) {
+        guard let t = target(id) else { return }
+        Task { await op(t); await refresh(id) }
+    }
+
+    /// Host load for a specific device (nil unless its backend reports stats).
+    public func deviceStats(_ id: String) async -> HostStats? {
+        guard let p = target(id) as? HostStatsProvider else { return nil }
+        return await p.stats()
+    }
+
+    /// Available releases of what a specific device is playing (empty unless its
+    /// backend can switch quality).
+    public func deviceReleases(_ id: String) async -> [Release] {
+        guard let q = target(id) as? QualitySwitchable else { return [] }
+        return await q.releases()
+    }
+
     /// Begin playback of a library request on the active target, then refresh it.
     /// `series`/`category` let the track preference (sub/dub) resolve and apply
     /// once the file is loaded; `resumeSeconds` seeks VLC/QuickTime to the saved
diff --git a/Sources/TVAnarchyCore/PlayerTarget.swift b/Sources/TVAnarchyCore/PlayerTarget.swift
index 36962f8..1a419c6 100644
--- a/Sources/TVAnarchyCore/PlayerTarget.swift
+++ b/Sources/TVAnarchyCore/PlayerTarget.swift
@@ -47,7 +47,7 @@ public protocol PlayerTarget: AnyObject {
     var id: String { get }
     var name: String { get }
     var kind: HostKind { get }
-    var detail: String { get }            // human-readable endpoint, for the Hosts view
+    var detail: String { get }            // human-readable endpoint, for the Devices view
     var volumeScale: Int { get }          // max value for the volume slider (percent)
 
     func poll() async -> PollResult
@@ -60,3 +60,16 @@ public protocol PlayerTarget: AnyObject {
     func previous() async
     func stop() async
 }
+
+/// A target whose backend can toggle fullscreen on its own display (VLC's HTTP
+/// `fullscreen` command). mpv-on-black already runs full-screen on the HDMI out,
+/// so only the windowed VLC player conforms — the Devices tab feature-detects it.
+public protocol FullscreenControllable: AnyObject {
+    func toggleFullscreen() async
+}
+
+/// A target whose backend keeps a playlist we can wipe in one shot (VLC's
+/// `pl_empty`). Surfaced as a per-service tool in the Devices detail pane.
+public protocol PlaylistClearable: AnyObject {
+    func clearPlaylist() async
+}
diff --git a/Sources/TVAnarchyCore/VLCTarget.swift b/Sources/TVAnarchyCore/VLCTarget.swift
index 17c1259..f6edb2a 100644
--- a/Sources/TVAnarchyCore/VLCTarget.swift
+++ b/Sources/TVAnarchyCore/VLCTarget.swift
@@ -4,7 +4,8 @@ import Foundation
 /// plum-control-mcp's vlc/client.ts. VLC's native volume is 0..512 (256 = 100%);
 /// normalized to percent here. The password is resolved from the portable-net-tv
 /// config, never stored in hosts.json.
-public final class VLCTarget: PlayerTarget, MediaLaunchable, Enqueueable, TrackSelectable {
+public final class VLCTarget: PlayerTarget, MediaLaunchable, Enqueueable, TrackSelectable,
+                              FullscreenControllable, PlaylistClearable {
     public let id: String
     public let name: String
     public let kind: HostKind = .vlc
@@ -158,6 +159,10 @@ public final class VLCTarget: PlayerTarget, MediaLaunchable, Enqueueable, TrackS
     public func previous() async { _ = await call("command=pl_previous") }
     public func stop() async { _ = await call("command=pl_stop") }
 
+    // MARK: Service tools (Devices tab)
+    public func toggleFullscreen() async { _ = await call("command=fullscreen") }
+    public func clearPlaylist() async { _ = await call("command=pl_empty") }
+
     private func numeric(_ v: Any?) -> Double? {
         if let d = v as? Double { return d }
         if let i = v as? Int { return Double(i) }
diff --git a/Tests/TVAnarchyCoreTests/FleetConfigTests.swift b/Tests/TVAnarchyCoreTests/FleetConfigTests.swift
new file mode 100644
index 0000000..e5f06af
--- /dev/null
+++ b/Tests/TVAnarchyCoreTests/FleetConfigTests.swift
@@ -0,0 +1,60 @@
+import XCTest
+@testable import TVAnarchyCore
+
+/// The fleet registry is additive to hosts.json and `loadOrSeed()` overwrites
+/// fleet.json on any decode failure (like HostsConfig), so the schema must
+/// round-trip and the seed must model the known home fleet correctly.
+final class FleetConfigTests: XCTestCase {
+    func testSeedModelsHomeFleet() {
+        let cfg = FleetConfig.seeded()
+        XCTAssertEqual(cfg.devices.map(\.id), ["black", "apricot", "plum", "phone"])
+
+        let black = cfg.devices[0]
+        XCTAssertEqual(black.deviceClass, .server)
+        XCTAssertTrue(black.alwaysOn)
+        XCTAssertEqual(black.duties, [.custodyFloor])
+        // black runs a *combo*: mpv playback + transmission.
+        XCTAssertEqual(black.services.map(\.kind), [.mpvIPC, .transmission])
+        XCTAssertEqual(black.playbackServices.map(\.kind), [.mpvIPC])
+
+        // apricot is the secondary always-on seeder + GPU/CPU offload, no playback.
+        let apricot = cfg.devices[1]
+        XCTAssertEqual(apricot.services.map(\.kind), [.transmission, .compute])
+        XCTAssertTrue(apricot.playbackServices.isEmpty)
+
+        // phone is a pure consumer — never a duty.
+        let phone = cfg.devices[3]
+        XCTAssertEqual(phone.deviceClass, .consumer)
+        XCTAssertTrue(phone.duties.isEmpty)
+        XCTAssertEqual(phone.services.map(\.kind), [.sink])
+    }
+
+    func testPlaybackServicesReferenceHostsByID() {
+        // Playback services must point at hosts.json ids so the live PlayerTarget
+        // is reused, not redefined.
+        let cfg = FleetConfig.seeded()
+        let blackMpv = cfg.devices[0].services.first { $0.kind == .mpvIPC }
+        XCTAssertEqual(blackMpv?.playbackHostID, "black")
+        let plumVlc = cfg.devices[2].services.first { $0.kind == .vlc }
+        XCTAssertEqual(plumVlc?.playbackHostID, "plum-vlc")
+        // Fleet-only services carry no playback host.
+        let transmission = cfg.devices[0].services.first { $0.kind == .transmission }
+        XCTAssertNil(transmission?.playbackHostID)
+    }
+
+    func testRoundTripPreservesEverything() throws {
+        let original = FleetConfig.seeded()
+        let data = try JSONEncoder().encode(original)
+        let decoded = try JSONDecoder().decode(FleetConfig.self, from: data)
+        XCTAssertEqual(decoded.devices, original.devices)
+    }
+
+    func testServiceKindPlaybackClassification() {
+        XCTAssertTrue(ServiceKind.mpvIPC.isPlayback)
+        XCTAssertTrue(ServiceKind.vlc.isPlayback)
+        XCTAssertTrue(ServiceKind.quicktime.isPlayback)
+        XCTAssertFalse(ServiceKind.transmission.isPlayback)
+        XCTAssertFalse(ServiceKind.compute.isPlayback)
+        XCTAssertFalse(ServiceKind.sink.isPlayback)
+    }
+}