fix(coding-agent): split /clone from /fork UX

closes #2962

packages/coding-agent/src/modes/interactive/components/user-message-selector.ts

@@ -120,8 +120,14 @@ export class UserMessageSelectorComponent extends Container {
 
 		// Add header
 		this.addChild(new Spacer(1));
-		this.addChild(new Text(theme.bold("Branch from Message"), 1, 0));
-		this.addChild(new Text(theme.fg("muted", "Select a message or duplicate the current session"), 1, 0));
+		this.addChild(new Text(theme.bold("Fork from Message"), 1, 0));
+		this.addChild(
+			new Text(
+				theme.fg("muted", "Select a user message to copy the active path up to that point into a new session"),
+				1,
+				0,
+			),
+		);
 		this.addChild(new Spacer(1));
 		this.addChild(new DynamicBorder());
 		this.addChild(new Spacer(1));

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -2425,6 +2425,11 @@ export class InteractiveMode {
 				this.editor.setText("");
 				return;
 			}
+			if (text === "/clone") {
+				this.editor.setText("");
+				await this.handleCloneCommand();
+				return;
+			}
 			if (text === "/tree") {
 				this.showTreeSelector();
 				this.editor.setText("");
@@ -3963,7 +3968,6 @@ export class InteractiveMode {
 	}
 
 	private showUserMessageSelector(): void {
-		const duplicateSessionOptionId = "__duplicate_session__";
 		const userMessages = this.session.getUserMessagesForForking();
 
 		if (userMessages.length === 0) {
@@ -3971,28 +3975,14 @@ export class InteractiveMode {
 			return;
 		}
 
-		const selectableEntries = [
-			...userMessages.map((m) => ({ id: m.entryId, text: m.text })),
-			{ id: duplicateSessionOptionId, text: "Duplicate session" },
-		];
 		const initialSelectedId = userMessages[userMessages.length - 1]?.entryId;
 
 		this.showSelector((done) => {
 			const selector = new UserMessageSelectorComponent(
-				selectableEntries,
+				userMessages.map((m) => ({ id: m.entryId, text: m.text })),
 				async (entryId) => {
 					try {
-						let result: { cancelled: boolean; selectedText?: string };
-						if (entryId === duplicateSessionOptionId) {
-							const leafId = this.sessionManager.getLeafId();
-							if (!leafId) {
-								throw new Error("Cannot duplicate session: no current entry selected");
-							}
-							result = await this.runtimeHost.fork(leafId, { position: "at" });
-						} else {
-							result = await this.runtimeHost.fork(entryId);
-						}
-
+						const result = await this.runtimeHost.fork(entryId);
 						if (result.cancelled) {
 							done();
 							this.ui.requestRender();
@@ -4003,7 +3993,7 @@ export class InteractiveMode {
 						this.renderCurrentSessionState();
 						this.editor.setText(result.selectedText ?? "");
 						done();
-						this.showStatus("Branched to new session");
+						this.showStatus("Forked to new session");
 					} catch (error: unknown) {
 						done();
 						this.showError(error instanceof Error ? error.message : String(error));
@@ -4019,6 +4009,29 @@ export class InteractiveMode {
 		});
 	}
 
+	private async handleCloneCommand(): Promise<void> {
+		const leafId = this.sessionManager.getLeafId();
+		if (!leafId) {
+			this.showStatus("Nothing to clone yet");
+			return;
+		}
+
+		try {
+			const result = await this.runtimeHost.fork(leafId, { position: "at" });
+			if (result.cancelled) {
+				this.ui.requestRender();
+				return;
+			}
+
+			await this.handleRuntimeSessionChange();
+			this.renderCurrentSessionState();
+			this.editor.setText("");
+			this.showStatus("Cloned to new session");
+		} catch (error: unknown) {
+			this.showError(error instanceof Error ? error.message : String(error));
+		}
+	}
+
 	private showTreeSelector(initialSelectedId?: string): void {
 		const tree = this.sessionManager.getTree();
 		const realLeafId = this.sessionManager.getLeafId();

packages/coding-agent/src/modes/rpc/rpc-client.ts

@@ -342,6 +342,15 @@ export class RpcClient {
 		return this.getData(response);
 	}
 
+	/**
+	 * Clone the current active branch into a new session.
+	 * @returns Object with `cancelled: true` if an extension cancelled the clone
+	 */
+	async clone(): Promise<{ cancelled: boolean }> {
+		const response = await this.send({ type: "clone" });
+		return this.getData(response);
+	}
+
 	/**
 	 * Get messages available for forking.
 	 */

packages/coding-agent/src/modes/rpc/rpc-mode.ts

@@ -567,6 +567,18 @@ export async function runRpcMode(runtimeHost: AgentSessionRuntime): Promise<neve
 				return success(id, "fork", { text: result.selectedText, cancelled: result.cancelled });
 			}
 
+			case "clone": {
+				const leafId = session.sessionManager.getLeafId();
+				if (!leafId) {
+					return error(id, "clone", "Cannot clone session: no current entry selected");
+				}
+				const result = await runtimeHost.fork(leafId, { position: "at" });
+				if (!result.cancelled) {
+					await rebindSession();
+				}
+				return success(id, "clone", { cancelled: result.cancelled });
+			}
+
 			case "get_fork_messages": {
 				const messages = session.getUserMessagesForForking();
 				return success(id, "get_fork_messages", { messages });

packages/coding-agent/src/modes/rpc/rpc-types.ts

@@ -57,6 +57,7 @@ export type RpcCommand =
 	| { id?: string; type: "export_html"; outputPath?: string }
 	| { id?: string; type: "switch_session"; sessionPath: string }
 	| { id?: string; type: "fork"; entryId: string }
+	| { id?: string; type: "clone" }
 	| { id?: string; type: "get_fork_messages" }
 	| { id?: string; type: "get_last_assistant_text" }
 	| { id?: string; type: "set_session_name"; name: string }
@@ -172,6 +173,7 @@ export type RpcResponse =
 	| { id?: string; type: "response"; command: "export_html"; success: true; data: { path: string } }
 	| { id?: string; type: "response"; command: "switch_session"; success: true; data: { cancelled: boolean } }
 	| { id?: string; type: "response"; command: "fork"; success: true; data: { text: string; cancelled: boolean } }
+	| { id?: string; type: "response"; command: "clone"; success: true; data: { cancelled: boolean } }
 	| {
 			id?: string;
 			type: "response";