fix: notify all open tabs when MCP settings change

- Modified McpHub.notifyWebviewOfServerChanges() to use McpServerManager.notifyProviders()
- This ensures all open tabs receive updates when MCP settings change
- Updated tests to mock McpServerManager instead of direct provider calls
- Fixes #8634

src/services/mcp/McpHub.ts

@@ -1319,27 +1319,19 @@ export class McpHub {
 			return aIsGlobal ? 1 : -1
 		})
 
-		// Send sorted servers to webview
-		const targetProvider: ClineProvider | undefined = this.providerRef.deref()
+		// Send sorted servers to all registered providers (all open tabs)
+		const serversToSend = sortedConnections.map((connection) => connection.server)
 
-		if (targetProvider) {
-			const serversToSend = sortedConnections.map((connection) => connection.server)
-
-			const message = {
-				type: "mcpServers" as const,
-				mcpServers: serversToSend,
-			}
-
-			try {
-				await targetProvider.postMessageToWebview(message)
-			} catch (error) {
-				console.error("[McpHub] Error calling targetProvider.postMessageToWebview:", error)
-			}
-		} else {
-			console.error(
-				"[McpHub] No target provider available (neither from getInstance nor providerRef) - cannot send mcpServers message to webview",
-			)
+		const message = {
+			type: "mcpServers" as const,
+			mcpServers: serversToSend,
 		}
+
+		// Import McpServerManager dynamically to avoid circular dependency
+		const { McpServerManager } = await import("./McpServerManager")
+
+		// Notify all registered providers to ensure all tabs are synchronized
+		McpServerManager.notifyProviders(message)
 	}
 
 	public async toggleServerDisabled(

src/services/mcp/__tests__/McpHub.spec.ts

@@ -49,6 +49,16 @@ vi.mock("../../../utils/safeWriteJson", () => ({
 	}),
 }))
 
+// Mock McpServerManager
+vi.mock("../McpServerManager", () => ({
+	McpServerManager: {
+		notifyProviders: vi.fn(),
+		getInstance: vi.fn(),
+		unregisterProvider: vi.fn(),
+		cleanup: vi.fn(),
+	},
+}))
+
 vi.mock("vscode", () => ({
 	workspace: {
 		createFileSystemWatcher: vi.fn().mockReturnValue({
@@ -1502,9 +1512,12 @@ describe("McpHub", () => {
 				}
 				mcpHub.connections = [mockConnection]
 
+				// Get the mock McpServerManager
+				const { McpServerManager } = await import("../McpServerManager")
+
 				await mcpHub.updateServerTimeout("test-server", 120)
 
-				expect(mockProvider.postMessageToWebview).toHaveBeenCalledWith(
+				expect(McpServerManager.notifyProviders).toHaveBeenCalledWith(
 					expect.objectContaining({
 						type: "mcpServers",
 					}),
@@ -1733,6 +1746,9 @@ describe("McpHub", () => {
 			const mcpHub = new McpHub(disabledMockProvider as unknown as ClineProvider)
 			await new Promise((resolve) => setTimeout(resolve, 100))
 
+			// Get the mock McpServerManager
+			const { McpServerManager } = await import("../McpServerManager")
+
 			// Clear previous calls
 			vi.clearAllMocks()
 
@@ -1746,8 +1762,8 @@ describe("McpHub", () => {
 			expect(server!.client).toBeNull()
 			expect(server!.transport).toBeNull()
 
-			// Verify postMessageToWebview was called to update the UI
-			expect(disabledMockProvider.postMessageToWebview).toHaveBeenCalledWith(
+			// Verify McpServerManager.notifyProviders was called to update the UI
+			expect(McpServerManager.notifyProviders).toHaveBeenCalledWith(
 				expect.objectContaining({
 					type: "mcpServers",
 				}),