fix(tui): consume extension slash commands locally

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed extension slash commands appearing as user prompts after being handled locally.
+
 ## [17.2.5] - 2026-08-03
 
 ### Breaking Changes

packages/coding-agent/src/modes/controllers/input-controller.ts

@@ -752,6 +752,25 @@ export class InputController {
 				}
 			}
 
+			// Extension commands are local actions. Execute them before the normal
+			// submission path creates an optimistic user message; otherwise a
+			// consumed command remains rendered like a prompt sent to the model.
+			const extensionCommandSpace = text.indexOf(" ");
+			const isLocalExtensionCommand =
+				text.startsWith("/") &&
+				runner?.getCommand(extensionCommandSpace === -1 ? text.slice(1) : text.slice(1, extensionCommandSpace)) !==
+					undefined;
+			if (isLocalExtensionCommand) {
+				this.ctx.editor.addToHistory(text);
+				try {
+					await this.ctx.session.prompt(text, { images: inputImages });
+				} catch (error) {
+					this.ctx.editor.setText(text);
+					this.ctx.showError(error instanceof Error ? error.message : String(error));
+				}
+				return;
+			}
+
 			// Handle bash command (! for normal, !! for excluded from context)
 			if (text.startsWith("!")) {
 				const isExcluded = text.startsWith("!!");

packages/coding-agent/test/input-controller-slash-history.test.ts

@@ -15,6 +15,7 @@ function makeCtx(isStreaming = false) {
 	const handleMCPCommand = vi.fn(async () => {});
 	const followUp = vi.fn(async (_text: string, _images?: ImageContent[]) => {});
 	const steer = vi.fn(async (_text: string, _images?: ImageContent[]) => {});
+	const prompt = vi.fn(async () => false);
 	const onInputCallback = vi.fn();
 	let text = "";
 	const editor = {
@@ -44,6 +45,7 @@ function makeCtx(isStreaming = false) {
 			extensionRunner: undefined,
 			followUp,
 			steer,
+			prompt,
 		},
 		focusedAgentId: undefined,
 		collabGuest: undefined,
@@ -75,6 +77,7 @@ function makeCtx(isStreaming = false) {
 		onInputCallback,
 		handleMCPCommand,
 		showStatus: ctx.showStatus,
+		prompt,
 	};
 }
 
@@ -117,6 +120,23 @@ describe("input controller — slash command history (#3148)", () => {
 		expect(addToHistory).not.toHaveBeenCalled();
 	});
 
+	it("executes extension commands without rendering them as user prompts", async () => {
+		const { ctx, editor, addToHistory, onInputCallback, prompt } = makeCtx();
+		Object.defineProperty(ctx.session, "extensionRunner", {
+			value: {
+				getCommand: (name: string) => (name === "id" ? { name } : undefined),
+				hasHandlers: () => false,
+			},
+		});
+		controllerFor(ctx);
+
+		await editor.onSubmit?.("/id");
+
+		expect(prompt).toHaveBeenCalledWith("/id", { images: undefined });
+		expect(addToHistory).toHaveBeenCalledWith("/id");
+		expect(onInputCallback).not.toHaveBeenCalled();
+	});
+
 	it("routes /queue through the yield-only follow-up queue while streaming", async () => {
 		const { ctx, editor, addToHistory, followUp, showStatus } = makeCtx(true);
 		controllerFor(ctx);