diff --git a/desktop/src/features/channels/lib/agentSessionPanelPresentation.test.mjs b/desktop/src/features/channels/lib/agentSessionPanelPresentation.test.mjs
index 9294d134a4..114466d176 100644
--- a/desktop/src/features/channels/lib/agentSessionPanelPresentation.test.mjs
+++ b/desktop/src/features/channels/lib/agentSessionPanelPresentation.test.mjs
@@ -14,6 +14,7 @@ test("the cover drawer owns motion and gets standalone, opaque chrome", () => {
       enterMotion: false,
       isSinglePanelView: true,
       layout: "standalone",
+      transcriptVariant: "conversation",
       transparentChrome: false,
     },
   );
@@ -30,6 +31,7 @@ test("the split pane keeps docked chrome and its own enter motion", () => {
       enterMotion: true,
       isSinglePanelView: false,
       layout: "split",
+      transcriptVariant: undefined,
       transparentChrome: true,
     },
   );
@@ -47,6 +49,7 @@ test("narrow viewports keep today's overlay and single-panel presentations", ()
         enterMotion: true,
         isSinglePanelView,
         layout: "standalone",
+        transcriptVariant: undefined,
         transparentChrome: false,
       },
     );
diff --git a/desktop/src/features/channels/lib/agentSessionPanelPresentation.ts b/desktop/src/features/channels/lib/agentSessionPanelPresentation.ts
index e7380da511..a22ad8d0c8 100644
--- a/desktop/src/features/channels/lib/agentSessionPanelPresentation.ts
+++ b/desktop/src/features/channels/lib/agentSessionPanelPresentation.ts
@@ -1,3 +1,5 @@
+import type { AgentSessionTranscriptVariant } from "@/features/agents/ui/agentSessionTranscriptContext";
+
 /**
  * `AnimatePresence` key shared by every agent activity presentation.
  *
@@ -11,6 +13,7 @@ export type AgentSessionPanelPresentation = {
   enterMotion: boolean;
   isSinglePanelView: boolean;
   layout: "standalone" | "split";
+  transcriptVariant: AgentSessionTranscriptVariant | undefined;
   transparentChrome: boolean;
 };
 
@@ -24,11 +27,11 @@ type AgentSessionPanelPresentationOptions = {
 /**
  * Maps channel presentation into the agent session panel's layout props.
  *
- * TODO(#6538): once the `conversation` transcript variant lands on main, this
- * should also return `transcriptVariant: "conversation"` for the cover drawer
- * and `undefined` otherwise, so the reading view is pinned by presentation
- * rather than inferred from panel width. The variant does not exist on main
- * yet, so the prop is deliberately not set here.
+ * The transcript variant is pinned here rather than inferred from panel width.
+ * The cover drawer is the reading surface, so it gets `conversation`; every
+ * other host keeps the dense activity feed. Width is a proxy that breaks — the
+ * split pane can be dragged wide and a narrow overlay can be tall — so the
+ * presentation that decided to cover is what decides the reading view too.
  */
 export function getAgentSessionPanelPresentation({
   isCoverDrawer,
@@ -44,6 +47,7 @@ export function getAgentSessionPanelPresentation({
       // it has no resizable neighbour to draw a resize border against.
       isSinglePanelView: true,
       layout: "standalone",
+      transcriptVariant: "conversation",
       transparentChrome: false,
     };
   }
@@ -52,6 +56,10 @@ export function getAgentSessionPanelPresentation({
     enterMotion: true,
     isSinglePanelView: useSplitAuxiliaryPane ? false : isSinglePanelView,
     layout: useSplitAuxiliaryPane ? "split" : "standalone",
+    // Undefined, not `"default"`: the panel already defaults, and naming it
+    // here would claim this function decides the non-cover variant when the
+    // profile panel's `compactPreview` is chosen at its own call site.
+    transcriptVariant: undefined,
     transparentChrome: useSplitAuxiliaryPane,
   };
 }
diff --git a/desktop/tests/e2e/agent-activity-cover-screenshots.spec.ts b/desktop/tests/e2e/agent-activity-cover-screenshots.spec.ts
index 9ae78b738d..0b69fcee81 100644
--- a/desktop/tests/e2e/agent-activity-cover-screenshots.spec.ts
+++ b/desktop/tests/e2e/agent-activity-cover-screenshots.spec.ts
@@ -465,6 +465,18 @@ test.describe("agent activity cover drawer screenshots", () => {
       page.getByTestId("transcript-user-message").first(),
     ).toBeVisible({ timeout: 10_000 });
 
+    // The reading view is pinned by presentation rather than inferred from panel
+    // width: the drawer is the reading surface, so its transcript renders the
+    // conversation variant. Asserted here rather than in
+    // `agent-activity-cover.spec.ts` because the marker only exists once the
+    // transcript has content, and this is the spec that seeds a turn. Asserted
+    // on the DOM marker rather than the prop so it proves the value survives the
+    // whole path from the presentation resolver through the panel.
+    await expect(panel.locator("[data-transcript-variant]")).toHaveAttribute(
+      "data-transcript-variant",
+      "conversation",
+    );
+
     await waitForAnimations(page);
     // Full window: the drawer against the sliver and the scrimmed channel,
     // which is the part of this presentation a panel-only shot cannot show.