fix(ui): surface slash command dispatch failures

## Summary
- surface inline Control UI feedback when local slash-command dispatch is unavailable or throws
- cover missing-client and unexpected-error paths for local slash commands
- note the user-facing fix in the changelog

Fixes #52105.

CHANGELOG.md

@@ -31,6 +31,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Control UI/chat: show inline feedback when local slash-command dispatch is unavailable or fails unexpectedly instead of clearing the composer silently. Fixes #52105. Thanks @MooreQiao.
 - Agents/tools: return critical tool-loop circuit-breaker stops as blocked tool results instead of thrown tool failures, so models see the guardrail and stop retrying the same call. Thanks @rayraiser.
 - Model commands: clarify direct and inline `/model` acknowledgements for non-default selections as session-scoped. Thanks @addu2612.
 - TUI/chat: skip full provider model normalization during context-window warmup while preserving provider-owned context metadata, avoiding cold-start stalls with large model registries. Thanks @547895019.

ui/src/ui/app-chat.test.ts

@@ -8,9 +8,13 @@ import {
   registerChatAttachmentPayload,
   resetChatAttachmentPayloadStoreForTest,
 } from "./chat/attachment-payload-store.ts";
+import type { executeSlashCommand } from "./chat/slash-command-executor.ts";
 import type { GatewaySessionRow, SessionsListResult } from "./types.ts";
 
-const { setLastActiveSessionKeyMock } = vi.hoisted(() => ({
+type ExecuteSlashCommand = typeof executeSlashCommand;
+
+const { executeSlashCommandMock, setLastActiveSessionKeyMock } = vi.hoisted(() => ({
+  executeSlashCommandMock: vi.fn(),
   setLastActiveSessionKeyMock: vi.fn(),
 }));
 
@@ -18,6 +22,21 @@ vi.mock("./app-last-active-session.ts", () => ({
   setLastActiveSessionKey: (...args: unknown[]) => setLastActiveSessionKeyMock(...args),
 }));
 
+vi.mock("./chat/slash-command-executor.ts", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("./chat/slash-command-executor.ts")>();
+  return {
+    ...actual,
+    executeSlashCommand: (...args: Parameters<ExecuteSlashCommand>) => {
+      const implementation = executeSlashCommandMock.getMockImplementation() as
+        | ExecuteSlashCommand
+        | undefined;
+      return implementation
+        ? executeSlashCommandMock(...args)
+        : actual.executeSlashCommand(...args);
+    },
+  };
+});
+
 let handleSendChat: typeof import("./app-chat.ts").handleSendChat;
 let steerQueuedChatMessage: typeof import("./app-chat.ts").steerQueuedChatMessage;
 let navigateChatInputHistory: typeof import("./app-chat.ts").navigateChatInputHistory;
@@ -420,6 +439,7 @@ describe("handleSendChat", () => {
   });
 
   beforeEach(() => {
+    executeSlashCommandMock.mockReset();
     setLastActiveSessionKeyMock.mockReset();
   });
 
@@ -619,6 +639,48 @@ describe("handleSendChat", () => {
     expect(onSlashAction).toHaveBeenCalledWith("refresh-tools-effective");
   });
 
+  it("shows local slash-command feedback when the gateway client is unavailable", async () => {
+    const host = makeHost({
+      client: null,
+      chatMessage: "/think",
+      connected: true,
+    });
+
+    await handleSendChat(host);
+
+    expect(host.chatMessage).toBe("");
+    expect(host.chatMessages).toEqual([
+      expect.objectContaining({
+        role: "system",
+        content: "Cannot run `/think`: Control UI is not connected to the Gateway.",
+      }),
+    ]);
+  });
+
+  it("shows local slash-command feedback when dispatch fails unexpectedly", async () => {
+    executeSlashCommandMock.mockRejectedValue(new Error("dispatch failed"));
+    const request = vi.fn(async (method: string) => {
+      throw new Error(`Unexpected request: ${method}`);
+    });
+    const host = makeHost({
+      client: { request } as unknown as ChatHost["client"],
+      chatMessage: "/think",
+      connected: true,
+    });
+
+    await handleSendChat(host);
+
+    expect(executeSlashCommandMock).toHaveBeenCalledTimes(1);
+    expect(host.chatMessage).toBe("");
+    expect(host.lastError).toBe("Error: dispatch failed");
+    expect(host.chatMessages).toEqual([
+      expect.objectContaining({
+        role: "system",
+        content: "Command `/think` failed unexpectedly.",
+      }),
+    ]);
+  });
+
   it("sends /btw immediately while a main run is active without queueing it", async () => {
     const request = vi.fn(async (method: string) => {
       if (method === "chat.send") {

ui/src/ui/app-chat.ts

@@ -567,15 +567,29 @@ async function dispatchSlashCommand(
       return;
   }
 
-  if (!host.client) {
+  if (!host.client || !host.connected) {
+    host.lastError = "Gateway not connected";
+    injectCommandResult(
+      host,
+      `Cannot run \`/${name}\`: Control UI is not connected to the Gateway.`,
+    );
+    scheduleChatScroll(host as unknown as Parameters<typeof scheduleChatScroll>[0]);
     return;
   }
 
   const targetSessionKey = host.sessionKey;
-  const result = await executeSlashCommand(host.client, targetSessionKey, name, args, {
-    chatModelCatalog: host.chatModelCatalog,
-    sessionsResult: host.sessionsResult,
-  });
+  let result: Awaited<ReturnType<typeof executeSlashCommand>>;
+  try {
+    result = await executeSlashCommand(host.client, targetSessionKey, name, args, {
+      chatModelCatalog: host.chatModelCatalog,
+      sessionsResult: host.sessionsResult,
+    });
+  } catch (err) {
+    host.lastError = String(err);
+    injectCommandResult(host, `Command \`/${name}\` failed unexpectedly.`);
+    scheduleChatScroll(host as unknown as Parameters<typeof scheduleChatScroll>[0]);
+    return;
+  }
 
   if (result.content) {
     injectCommandResult(host, result.content);