diff --git a/desktop/src/features/channels/ui/ChannelPane.tsx b/desktop/src/features/channels/ui/ChannelPane.tsx
index 8a4e4a92b1..95dffd527f 100644
--- a/desktop/src/features/channels/ui/ChannelPane.tsx
+++ b/desktop/src/features/channels/ui/ChannelPane.tsx
@@ -31,6 +31,7 @@ import { ChannelManagementAuxiliaryPanel } from "@/features/channels/ui/ChannelM
 import { IdleAuxiliaryPanel } from "@/features/channels/ui/IdleAuxiliaryPanel";
 import { MarkdownDocAuxiliaryPanel } from "@/features/channels/ui/MarkdownDocAuxiliaryPanel";
 import { RightAuxiliaryPane } from "@/features/channels/ui/RightAuxiliaryPane";
+import { createChannelPaneAuxiliaryLayout } from "@/features/channels/ui/channelPaneAuxiliaryLayout";
 import {
   ThreadPanelSurface,
   useThreadPanelSurface,
@@ -51,11 +52,7 @@ import {
   WelcomeComposerGuidanceLayer,
 } from "@/features/channels/ui/WelcomeComposerBanner";
 import { useWelcomeComposerBanner } from "@/features/channels/ui/useWelcomeComposerBanner";
-import {
-  mentionsKnownAgent,
-  shouldPrioritizeIdleAuxiliary,
-  shouldUseFocusIdleDrawer,
-} from "@/features/channels/ui/ChannelPane.helpers";
+import { mentionsKnownAgent } from "@/features/channels/ui/ChannelPane.helpers";
 import { HuddleStartingView, HuddleTranscriptIntro } from "@/features/huddle";
 import { ChannelGlyph } from "@/features/channels/ui/ChannelGlyph";
 import { useSearchHighlightProps } from "@/features/channels/ui/useSearchHighlightProps";
@@ -425,12 +422,7 @@ export const ChannelPane = React.memo(function ChannelPane({
     threadHeadMessage,
   ]);
   const isOverlay = useIsThreadPanelOverlay();
-  const useSplitAuxiliaryPane = !isSinglePanelView && !isOverlay;
   const threadViewMode = useThreadViewMode();
-  const hasThreadSurface =
-    Boolean(threadHeadMessage) || shouldShowThreadSkeleton;
-  const useFocusThreadDrawer =
-    threadViewMode === "focus" && useSplitAuxiliaryPane && hasThreadSurface;
   const selectedAgent = React.useMemo(
     () =>
       agentSessionSelection.resolveSelectedAgentSession({
@@ -441,28 +433,29 @@ export const ChannelPane = React.memo(function ChannelPane({
       }),
     [agentSessionAgents, openAgentSessionPubkey, profilePanelPubkey, profiles],
   );
-  const hasIdleAuxiliary =
-    Boolean(idleAuxiliaryPanel) && Boolean(onCloseIdleAuxiliaryPanel);
-  const priorityIdleAuxiliary = shouldPrioritizeIdleAuxiliary(
-    idleAuxiliaryOverridesThread,
-    hasIdleAuxiliary,
-  );
-  const overlayIdleAuxiliaryOverThread =
-    priorityIdleAuxiliary && hasThreadSurface && !isOverlay;
-  const replaceThreadWithIdleAuxiliary =
-    priorityIdleAuxiliary && hasThreadSurface && isOverlay;
-  const useFocusIdleDrawer = shouldUseFocusIdleDrawer({
+  const {
+    hasSplitAuxiliaryPane,
+    openMarkdownDoc,
+    priorityIdleAuxiliary,
+    replaceThreadWithIdleAuxiliary,
+    showIdleAuxiliaryOverThread,
+    useFocusIdleDrawer,
+    useFocusThreadDrawer,
+    useSplitAuxiliaryPane,
+  } = createChannelPaneAuxiliaryLayout({
     channelManagementOpen,
     hasAgentSession: Boolean(activeChannel && selectedAgent),
     hasIdleAuxiliaryPanel: Boolean(idleAuxiliaryPanel),
     hasIdlePanelCloseHandler: Boolean(onCloseIdleAuxiliaryPanel),
     hasProfilePanel: Boolean(profilePanelPubkey),
-    hasThreadSurface,
-    overrideThread: overlayIdleAuxiliaryOverThread,
-    useSplitAuxiliaryPane,
+    hasThreadSurface: Boolean(threadHeadMessage) || shouldShowThreadSkeleton,
+    idleAuxiliaryOverridesThread,
+    isOverlay,
+    isSinglePanelView,
+    markdownDocName,
+    markdownDocUrl,
+    threadViewMode,
   });
-  const showIdleAuxiliaryOverThread =
-    overlayIdleAuxiliaryOverThread && useFocusIdleDrawer;
   const { channelIsCovered, markExitComplete } = useFocusDrawerPresence(
     useFocusThreadDrawer || useFocusIdleDrawer,
     priorityIdleAuxiliary
@@ -499,17 +492,6 @@ export const ChannelPane = React.memo(function ChannelPane({
     threadMessages: threadMessages.map((entry) => entry.message),
     useFocusThreadDrawer,
   });
-  const openMarkdownDoc =
-    markdownDocUrl && markdownDocName
-      ? { filename: markdownDocName, url: markdownDocUrl }
-      : null;
-  const hasSplitAuxiliaryPane =
-    useSplitAuxiliaryPane &&
-    (channelManagementOpen ||
-      Boolean(threadHeadMessage) ||
-      shouldShowThreadSkeleton ||
-      Boolean(activeChannel && selectedAgent) ||
-      Boolean(profilePanelPubkey));
   const wrapAux = (
     panel: React.ReactNode,
     testId: string,
@@ -803,8 +785,6 @@ export const ChannelPane = React.memo(function ChannelPane({
                     }
                     showTopBorder={false}
                   />
-                  {/* The reserved bottom rail keeps accessory fades from moving
-                    the conversation while content remains responsive. */}
                   <ChannelComposerActivityAccessory
                     agents={activityAgents}
                     channel={activeChannel}
@@ -825,7 +805,6 @@ export const ChannelPane = React.memo(function ChannelPane({
           </div>
         </section>
       ) : null}
-      {/* Serialize replacements so focus drawers keep one travel direction. */}
       <AnimatePresence mode="wait" onExitComplete={markExitComplete}>
         {channelManagementOpen && activeChannel ? (
           <ChannelManagementAuxiliaryPanel
diff --git a/desktop/src/features/channels/ui/channelPaneAuxiliaryLayout.ts b/desktop/src/features/channels/ui/channelPaneAuxiliaryLayout.ts
new file mode 100644
index 0000000000..2dfc8f1a36
--- /dev/null
+++ b/desktop/src/features/channels/ui/channelPaneAuxiliaryLayout.ts
@@ -0,0 +1,80 @@
+import {
+  shouldPrioritizeIdleAuxiliary,
+  shouldUseFocusIdleDrawer,
+} from "./ChannelPane.helpers";
+
+type ChannelPaneAuxiliaryLayoutOptions = {
+  channelManagementOpen: boolean;
+  hasAgentSession: boolean;
+  hasIdleAuxiliaryPanel: boolean;
+  hasIdlePanelCloseHandler: boolean;
+  hasProfilePanel: boolean;
+  hasThreadSurface: boolean;
+  idleAuxiliaryOverridesThread: boolean;
+  isOverlay: boolean;
+  isSinglePanelView: boolean;
+  markdownDocName?: string | null;
+  markdownDocUrl?: string | null;
+  threadViewMode: string;
+};
+
+export function createChannelPaneAuxiliaryLayout({
+  channelManagementOpen,
+  hasAgentSession,
+  hasIdleAuxiliaryPanel,
+  hasIdlePanelCloseHandler,
+  hasProfilePanel,
+  hasThreadSurface,
+  idleAuxiliaryOverridesThread,
+  isOverlay,
+  isSinglePanelView,
+  markdownDocName,
+  markdownDocUrl,
+  threadViewMode,
+}: ChannelPaneAuxiliaryLayoutOptions) {
+  const useSplitAuxiliaryPane = !isSinglePanelView && !isOverlay;
+  const useFocusThreadDrawer =
+    threadViewMode === "focus" && useSplitAuxiliaryPane && hasThreadSurface;
+  const hasIdleAuxiliary = hasIdleAuxiliaryPanel && hasIdlePanelCloseHandler;
+  const priorityIdleAuxiliary = shouldPrioritizeIdleAuxiliary(
+    idleAuxiliaryOverridesThread,
+    hasIdleAuxiliary,
+  );
+  const overlayIdleAuxiliaryOverThread =
+    priorityIdleAuxiliary && hasThreadSurface && !isOverlay;
+  const replaceThreadWithIdleAuxiliary =
+    priorityIdleAuxiliary && hasThreadSurface && isOverlay;
+  const useFocusIdleDrawer = shouldUseFocusIdleDrawer({
+    channelManagementOpen,
+    hasAgentSession,
+    hasIdleAuxiliaryPanel,
+    hasIdlePanelCloseHandler,
+    hasProfilePanel,
+    hasThreadSurface,
+    overrideThread: overlayIdleAuxiliaryOverThread,
+    useSplitAuxiliaryPane,
+  });
+
+  const openMarkdownDoc =
+    markdownDocUrl && markdownDocName
+      ? { filename: markdownDocName, url: markdownDocUrl }
+      : null;
+  const hasSplitAuxiliaryPane =
+    useSplitAuxiliaryPane &&
+    (channelManagementOpen ||
+      hasThreadSurface ||
+      hasAgentSession ||
+      hasProfilePanel);
+
+  return {
+    hasSplitAuxiliaryPane,
+    openMarkdownDoc,
+    priorityIdleAuxiliary,
+    replaceThreadWithIdleAuxiliary,
+    showIdleAuxiliaryOverThread:
+      overlayIdleAuxiliaryOverThread && useFocusIdleDrawer,
+    useFocusIdleDrawer,
+    useFocusThreadDrawer,
+    useSplitAuxiliaryPane,
+  };
+}