diff --git a/packages/coding-agent/src/modes/components/tree-selector.ts b/packages/coding-agent/src/modes/components/tree-selector.ts
index c3f88d959..33a8c00cc 100644
--- a/packages/coding-agent/src/modes/components/tree-selector.ts
+++ b/packages/coding-agent/src/modes/components/tree-selector.ts
@@ -852,7 +852,8 @@ class TreeList implements Component {
 		} else if (
 			matchesKey(keyData, "shift+enter") ||
 			matchesKey(keyData, "shift+return") ||
-			keyData === "\n" // Shift+Enter delivered as bare LF (iTerm2 legacy mapping) — matches the composer (issue #8821)
+			keyData === "\n" || // Shift+Enter delivered as bare LF (iTerm2 legacy mapping) — matches the composer (issue #8821)
+			keyData === "\x1b[13;2~" // Shift+Enter legacy CSI ~ form — also accepted by the composer (editor.ts:1466)
 		) {
 			// Summarize-and-switch: fork with a branch summary without the extra prompt.
 			const selected = this.#filteredNodes[this.#selectedIndex];
diff --git a/packages/coding-agent/test/modes/components/tree-selector-shift-enter-8821.test.ts b/packages/coding-agent/test/modes/components/tree-selector-shift-enter-8821.test.ts
index 70bd6a12a..c48e22a9d 100644
--- a/packages/coding-agent/test/modes/components/tree-selector-shift-enter-8821.test.ts
+++ b/packages/coding-agent/test/modes/components/tree-selector-shift-enter-8821.test.ts
@@ -80,10 +80,10 @@ describe("tree selector Shift+Enter fallback (issue #8821)", () => {
 		expect(records).toEqual([{ entryId: responseEntry.id, options: { summarize: true } }]);
 	});
 
-	it("leaves the legacy CSI ~ form alone (parsed as shift+f3, not Enter)", () => {
+	it("treats the legacy CSI ~ form as Shift+Enter (summarize-and-switch), matching the composer", () => {
 		const records: SelectRecord[] = [];
 		const { selector } = selectorWithOnSelect([userEntry, responseEntry], records);
 		selector.handleInput("\u001b[13;2~");
-		expect(records).toEqual([]);
+		expect(records).toEqual([{ entryId: responseEntry.id, options: { summarize: true } }]);
 	});
 });