diff --git a/packages/cli/src/ui/hooks/useGeminiStream.ts b/packages/cli/src/ui/hooks/useGeminiStream.ts
index 9dcb005b..76d29189 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.ts
+++ b/packages/cli/src/ui/hooks/useGeminiStream.ts
@@ -109,7 +109,10 @@ export const useGeminiStream = (
     if (
       isResponding ||
       toolCalls.some(
-        (t) => t.status === 'executing' || t.status === 'scheduled',
+        (t) =>
+          t.status === 'executing' ||
+          t.status === 'scheduled' ||
+          t.status === 'validating',
       )
     ) {
       return StreamingState.Responding;
diff --git a/packages/cli/src/ui/hooks/useToolScheduler.ts b/packages/cli/src/ui/hooks/useToolScheduler.ts
index a5770d36..1bb44133 100644
--- a/packages/cli/src/ui/hooks/useToolScheduler.ts
+++ b/packages/cli/src/ui/hooks/useToolScheduler.ts
@@ -20,6 +20,12 @@ import {
   ToolCallStatus,
 } from '../types.js';
 
+type ValidatingToolCall = {
+  status: 'validating';
+  request: ToolCallRequestInfo;
+  tool: Tool;
+};
+
 type ScheduledToolCall = {
   status: 'scheduled';
   request: ToolCallRequestInfo;
@@ -62,6 +68,7 @@ type WaitingToolCall = {
 export type Status = ToolCall['status'];
 
 export type ToolCall =
+  | ValidatingToolCall
   | ScheduledToolCall
   | ErroredToolCall
   | SuccessfulToolCall
@@ -99,9 +106,12 @@ export function useToolScheduler(
           'Cannot schedule tool calls while other tool calls are running',
         );
       }
-      const requests = Array.isArray(request) ? request : [request];
-      const newCalls: ToolCall[] = await Promise.all(
-        requests.map(async (r): Promise<ToolCall> => {
+      const requestsToProcess = Array.isArray(request) ? request : [request];
+
+      // Step 1: Create initial calls with 'validating' status (or 'error' if tool not found)
+      // and add them to the state immediately to make the UI busy.
+      const initialNewCalls: ToolCall[] = requestsToProcess.map(
+        (r): ToolCall => {
           const tool = toolRegistry.getTool(r.name);
           if (!tool) {
             return {
@@ -113,16 +123,27 @@ export function useToolScheduler(
               ),
             };
           }
+          // Set to 'validating' immediately. This will make streamingState 'Responding'.
+          return { status: 'validating', request: r, tool };
+        },
+      );
+      setToolCalls((prevCalls) => prevCalls.concat(initialNewCalls));
 
+      // Step 2: Asynchronously check for confirmation and update status for each new call.
+      initialNewCalls.forEach(async (initialCall) => {
+        // If the call was already marked as an error (tool not found), skip further processing.
+        if (initialCall.status !== 'validating') return;
+
+        const { request: r, tool } = initialCall;
+        try {
           const userApproval = await tool.shouldConfirmExecute(r.args);
           if (userApproval) {
-            return {
-              status: 'awaiting_approval',
-              request: r,
-              tool,
-              confirmationDetails: {
+            // Confirmation is needed. Update status to 'awaiting_approval'.
+            setToolCalls(
+              setStatus(r.callId, 'awaiting_approval', {
                 ...userApproval,
                 onConfirm: async (outcome) => {
+                  // This onConfirm is triggered by user interaction later.
                   await userApproval.onConfirm(outcome);
                   setToolCalls(
                     outcome === ToolConfirmationOutcome.Cancel
@@ -131,21 +152,30 @@ export function useToolScheduler(
                           'cancelled',
                           'User did not allow tool call',
                         )
-                      : setStatus(r.callId, 'scheduled'),
+                      : // If confirmed, it goes to 'scheduled' to be picked up by the execution effect.
+                        setStatus(r.callId, 'scheduled'),
                   );
                 },
-              },
-            };
+              }),
+            );
+          } else {
+            // No confirmation needed, move to 'scheduled' for execution.
+            setToolCalls(setStatus(r.callId, 'scheduled'));
           }
-
-          return {
-            status: 'scheduled',
-            request: r,
-            tool,
-          };
-        }),
-      );
-      setToolCalls((t) => t.concat(newCalls));
+        } catch (e) {
+          // Handle errors from tool.shouldConfirmExecute() itself.
+          setToolCalls(
+            setStatus(
+              r.callId,
+              'error',
+              toolErrorResponse(
+                r,
+                e instanceof Error ? e : new Error(String(e)),
+              ),
+            ),
+          );
+        }
+      });
     },
     [isRunning, setToolCalls, toolRegistry],
   );
@@ -273,7 +303,7 @@ function setStatus(
 ): (t: ToolCall[]) => ToolCall[];
 function setStatus(
   targetCallId: string,
-  status: 'executing' | 'scheduled',
+  status: 'executing' | 'scheduled' | 'validating',
 ): (t: ToolCall[]) => ToolCall[];
 function setStatus(
   targetCallId: string,
@@ -338,6 +368,13 @@ function setStatus(
           };
           return next;
         }
+        case 'validating': {
+          const next: ValidatingToolCall = {
+            ...(t as ValidatingToolCall), // Added type assertion for safety
+            status: 'validating',
+          };
+          return next;
+        }
         case 'executing': {
           const next: ExecutingToolCall = {
             ...t,
@@ -373,6 +410,8 @@ const toolErrorResponse = (
 
 function mapStatus(status: Status): ToolCallStatus {
   switch (status) {
+    case 'validating':
+      return ToolCallStatus.Executing;
     case 'awaiting_approval':
       return ToolCallStatus.Confirming;
     case 'executing':
@@ -445,6 +484,15 @@ export function mapToDisplay(
           status: mapStatus(t.status),
           confirmationDetails: undefined,
         };
+      case 'validating': // Add this case
+        return {
+          callId: t.request.callId,
+          name: t.tool.displayName,
+          description: t.tool.getDescription(t.request.args),
+          resultDisplay: undefined,
+          status: mapStatus(t.status),
+          confirmationDetails: undefined,
+        };
       case 'scheduled':
         return {
           callId: t.request.callId,