fix(extensions): harden mcp diagnostics runtime guards

src/renderer/components/extensions/mcp/McpServersPanel.tsx

@@ -100,6 +100,7 @@ export const McpServersPanel = ({
     mcpDiagnosticsLastCheckedAtFallback,
     runMcpDiagnostics,
     cliStatus,
+    cliStatusLoading,
   } = useStore(
     useShallow((s) => ({
       browseCatalog: s.mcpBrowseCatalog,
@@ -120,6 +121,7 @@ export const McpServersPanel = ({
       mcpDiagnosticsLastCheckedAtFallback: s.mcpDiagnosticsLastCheckedAt,
       runMcpDiagnostics: s.runMcpDiagnostics,
       cliStatus: s.cliStatus,
+      cliStatusLoading: s.cliStatusLoading,
     }))
   );
   const installedServers =
@@ -144,9 +146,27 @@ export const McpServersPanel = ({
     }
   }, [browseCatalog.length, browseError, browseLoading, mcpBrowse]);
 
+  const diagnosticsDisableReason = useMemo(() => {
+    if (cliStatusLoading) {
+      return 'Checking runtime status...';
+    }
+
+    if (cliStatus?.installed === false) {
+      if (cliStatus.binaryPath && cliStatus.launchError) {
+        return 'The configured runtime was found but failed to start. Open the Dashboard to repair or reinstall it.';
+      }
+      return 'The configured runtime is required. Install or repair it from the Dashboard.';
+    }
+
+    return null;
+  }, [cliStatus, cliStatusLoading]);
+
   useEffect(() => {
+    if (diagnosticsDisableReason) {
+      return;
+    }
     void runMcpDiagnostics(projectPath ?? undefined);
-  }, [projectPath, runMcpDiagnostics]);
+  }, [diagnosticsDisableReason, projectPath, runMcpDiagnostics]);
 
   // Fetch GitHub stars after catalog loads (fire-and-forget)
   useEffect(() => {
@@ -240,6 +260,8 @@ export const McpServersPanel = ({
             <p className="text-xs text-text-muted">
               {mcpDiagnosticsLoading ? (
                 <>Checking installed MCP servers via {runtimeLabel} ...</>
+              ) : diagnosticsDisableReason ? (
+                diagnosticsDisableReason
               ) : mcpDiagnosticsLastCheckedAt ? (
                 `Last checked ${formatRelativeTime(new Date(mcpDiagnosticsLastCheckedAt).toISOString())}`
               ) : (
@@ -251,7 +273,7 @@ export const McpServersPanel = ({
             variant="outline"
             size="sm"
             onClick={() => void runMcpDiagnostics(projectPath ?? undefined)}
-            disabled={mcpDiagnosticsLoading}
+            disabled={mcpDiagnosticsLoading || Boolean(diagnosticsDisableReason)}
             className="whitespace-nowrap"
           >
             <RefreshCw
@@ -299,9 +321,7 @@ export const McpServersPanel = ({
                 ))}
               </div>
             ) : (
-              <p className="text-xs text-text-muted">
-                Waiting for <code>{diagnosticsCommand}</code> results...
-              </p>
+              <p className="text-xs text-text-muted">Waiting for diagnostics results...</p>
             )}
           </div>
         )}

test/renderer/components/extensions/mcp/McpServersPanel.test.ts

@@ -34,8 +34,12 @@ interface StoreState {
   mcpDiagnosticsLastCheckedAt: number | null;
   mcpDiagnosticsLastCheckedAtByProjectPath?: Record<string, number | null>;
   runMcpDiagnostics: ReturnType<typeof vi.fn>;
+  cliStatusLoading: boolean;
   cliStatus?: {
     flavor?: 'claude' | 'agent_teams_orchestrator';
+    installed?: boolean;
+    binaryPath?: string | null;
+    launchError?: string | null;
   };
 }
 
@@ -144,6 +148,7 @@ describe('McpServersPanel initial browse loading', () => {
     storeState.mcpDiagnosticsLastCheckedAt = null;
     storeState.mcpDiagnosticsLastCheckedAtByProjectPath = undefined;
     storeState.runMcpDiagnostics = vi.fn();
+    storeState.cliStatusLoading = false;
     storeState.cliStatus = undefined;
   });
 
@@ -309,4 +314,79 @@ describe('McpServersPanel initial browse loading', () => {
       await Promise.resolve();
     });
   });
+
+  it('does not auto-run diagnostics when the configured runtime is unavailable', async () => {
+    storeState.cliStatus = {
+      flavor: 'agent_teams_orchestrator',
+      installed: false,
+      binaryPath: null,
+      launchError: null,
+    };
+
+    const host = document.createElement('div');
+    document.body.appendChild(host);
+    const root = createRoot(host);
+
+    await act(async () => {
+      root.render(
+        React.createElement(McpServersPanel, {
+          projectPath: null,
+          mcpSearchQuery: '',
+          mcpSearch: vi.fn(),
+          mcpSearchResults: [],
+          mcpSearchLoading: false,
+          mcpSearchWarnings: [],
+          selectedMcpServerId: null,
+          setSelectedMcpServerId: vi.fn(),
+        })
+      );
+      await Promise.resolve();
+    });
+
+    expect(storeState.runMcpDiagnostics).not.toHaveBeenCalled();
+    expect(host.textContent).toContain(
+      'The configured runtime is required. Install or repair it from the Dashboard.'
+    );
+    const checkStatusButton = Array.from(host.querySelectorAll('button')).find((button) =>
+      button.textContent?.includes('Check Status')
+    );
+    expect(checkStatusButton).toBeDefined();
+    expect((checkStatusButton as HTMLButtonElement).disabled).toBe(true);
+
+    await act(async () => {
+      root.unmount();
+      await Promise.resolve();
+    });
+  });
+
+  it('renders provider-neutral waiting copy while diagnostics are still running', async () => {
+    storeState.mcpDiagnosticsLoading = true;
+
+    const host = document.createElement('div');
+    document.body.appendChild(host);
+    const root = createRoot(host);
+
+    await act(async () => {
+      root.render(
+        React.createElement(McpServersPanel, {
+          projectPath: null,
+          mcpSearchQuery: '',
+          mcpSearch: vi.fn(),
+          mcpSearchResults: [],
+          mcpSearchLoading: false,
+          mcpSearchWarnings: [],
+          selectedMcpServerId: null,
+          setSelectedMcpServerId: vi.fn(),
+        })
+      );
+      await Promise.resolve();
+    });
+
+    expect(host.textContent).toContain('Waiting for diagnostics results...');
+
+    await act(async () => {
+      root.unmount();
+      await Promise.resolve();
+    });
+  });
 });