diff --git a/.lane/memory/apps/app/src/channel.tsx/01M4YQY84K8XSFAWY9R9YCMF5C-sidebar-totals-stay-per-grou.md b/.lane/memory/apps/app/src/channel.tsx/01M4YQY84K8XSFAWY9R9YCMF5C-sidebar-totals-stay-per-grou.md
index 18848dfd..ed2ec57c 100644
--- a/.lane/memory/apps/app/src/channel.tsx/01M4YQY84K8XSFAWY9R9YCMF5C-sidebar-totals-stay-per-grou.md
+++ b/.lane/memory/apps/app/src/channel.tsx/01M4YQY84K8XSFAWY9R9YCMF5C-sidebar-totals-stay-per-grou.md
@@ -4,9 +4,9 @@ anchor: function ChannelDetails
 created: 2026-10-15T02:58:24Z
 norm: '1'
 sig: b49433e7f0d6d4f3
-body_hash: 0ad294e254dbf4a9
-raw_hash: 12a00ec745e4b2fa
-vouched: 2026-10-16T22:31:01Z
+body_hash: c78ae37103f4096d
+raw_hash: 7d353ff7240b0bf1
+vouched: 2026-10-22T16:29:20Z
 lines: 161-209
 ---
 
diff --git a/apps/app/src/channel.tsx b/apps/app/src/channel.tsx
index a4a0766a..c8e27b18 100644
--- a/apps/app/src/channel.tsx
+++ b/apps/app/src/channel.tsx
@@ -9,7 +9,7 @@ import {
 	useSyncExternalStore,
 } from "react";
 
-import type { Changes, GithubPull } from "@ace/channel/protocol";
+import type { Change, Changes, GithubPull } from "@ace/channel/protocol";
 import type { ChannelInfo, Listing } from "@ace/host/protocol";
 import {
 	Badge,
@@ -233,20 +233,27 @@ export function ChannelDetails({ channel, user }: { channel: Listing; user: stri
 		// Totaled per group as the Diff does, so uncommitted and untracked files never inflate the
 		// committed work a pull request would show.
 		const groups = new Map<string | undefined, DetailsChanges>();
-		const add = (group: string | undefined, adds: number, dels: number, files: number) => {
+		const add = (group: string | undefined, files: number, file?: Change) => {
 			let sum = groups.get(group);
 			if (!sum) {
-				groups.set(group, sum = { ...(group ? { group } : {}), adds: 0, dels: 0, files: 0 });
+				groups.set(
+					group,
+					sum = { ...(group ? { group } : {}), adds: 0, dels: 0, files: 0, lines: false },
+				);
 			}
-			sum.adds += adds;
-			sum.dels += dels;
 			sum.files += files;
+			// Large untracked directories are only counted, so their group's line totals are unknown.
+			if (!file) sum.lines = false;
+			else if (!file.binary) {
+				sum.adds += file.adds;
+				sum.dels += file.dels;
+				sum.lines = true;
+			}
 		};
-		for (const file of changes.files) {
-			add(file.state && GROUPS[file.state], file.adds, file.dels, 1);
-		}
-		for (const { files } of changes.dirs || []) add(GROUPS.untracked, 0, 0, files);
-		return groups.size ? [...groups.values()] : [{ adds: 0, dels: 0, files: 0 }];
+		for (const file of changes.files) add(file.state && GROUPS[file.state], 1, file);
+		// After every file, so no file's lines mark a directory's group known again.
+		for (const { files } of changes.dirs || []) add(GROUPS.untracked, files);
+		return groups.size ? [...groups.values()] : [{ adds: 0, dels: 0, files: 0, lines: true }];
 	}, [changes]);
 	const mentioned = useMemo(() => items && links(items, channel.repo), [items, channel.repo]);
 	const agents = useMemo(() => items && subagents(items, busy), [items, busy]);
diff --git a/packages/ui/src/components/session-details/session-details.tsx b/packages/ui/src/components/session-details/session-details.tsx
index 6b961588..b110ee5a 100644
--- a/packages/ui/src/components/session-details/session-details.tsx
+++ b/packages/ui/src/components/session-details/session-details.tsx
@@ -43,7 +43,14 @@ export type DetailsLink = { url: string; label: string; kind: "issue" | "pull" |
 export type DetailsFact = { label: string; value: string; title?: string };
 type Icon = ComponentType<{ className?: string }>;
 /** One group's totals, such as committed or untracked files; ungrouped totals omit `group`. */
-export type DetailsChanges = { group?: string; adds: number; dels: number; files: number };
+export type DetailsChanges = {
+	group?: string;
+	adds: number;
+	dels: number;
+	files: number;
+	/** Whether `adds` and `dels` are known; untracked directories and binary files have none. */
+	lines: boolean;
+};
 
 export type SessionDetailsViewProps = {
 	summary?: string;
@@ -129,15 +136,19 @@ function Changes({ changes, onDiff }: { changes: DetailsChanges; onDiff?: () =>
 	const files = `${changes.files.toLocaleString()} ${changes.files === 1 ? "file" : "files"}`;
 	const adds = `${changes.adds} ${changes.adds === 1 ? "addition" : "additions"}`;
 	const dels = `${changes.dels} ${changes.dels === 1 ? "deletion" : "deletions"}`;
-	const label = `${name}: ${files}, ${adds}, ${dels}`;
+	const label = changes.lines ? `${name}: ${files}, ${adds}, ${dels}` : `${name}: ${files}`;
 	const content = (
 		<>
 			<IconFileDiff className={cn(GLYPH, "text-muted-foreground")} aria-hidden />
 			<span className="min-w-0 truncate">{name}</span>
 			<span className="ml-auto flex shrink-0 gap-1.5 font-medium tabular-nums">
 				{changes.group && <span className="font-normal text-muted-foreground">{files}</span>}
-				<span className="text-success">+{changes.adds.toLocaleString()}</span>
-				<span className="text-destructive">-{changes.dels.toLocaleString()}</span>
+				{changes.lines && (
+					<>
+						<span className="text-success">+{changes.adds.toLocaleString()}</span>
+						<span className="text-destructive">-{changes.dels.toLocaleString()}</span>
+					</>
+				)}
 			</span>
 		</>
 	);