feat: add permission request UI for sensitive tool operations

components/frontend/src/components/session/ask-user-question.tsx

@@ -8,11 +8,12 @@ import { Input } from "@/components/ui/input";
 import { RadioGroup, RadioGroupItem } from "@/components/ui/radio-group";
 import { HelpCircle, CheckCircle2, Send, ChevronRight } from "lucide-react";
 import { formatTimestamp } from "@/lib/format-timestamp";
-import type {
-  ToolUseBlock,
-  ToolResultBlock,
-  AskUserQuestionItem,
-  AskUserQuestionInput,
+import {
+  hasToolResult,
+  type ToolUseBlock,
+  type ToolResultBlock,
+  type AskUserQuestionItem,
+  type AskUserQuestionInput,
 } from "@/types/agentic-session";
 
 export type AskUserQuestionMessageProps = {
@@ -41,14 +42,6 @@ function parseQuestions(input: Record<string, unknown>): AskUserQuestionItem[] {
   return [];
 }
 
-function hasResult(resultBlock?: ToolResultBlock): boolean {
-  if (!resultBlock) return false;
-  const content = resultBlock.content;
-  if (!content) return false;
-  if (typeof content === "string" && content.trim() === "") return false;
-  return true;
-}
-
 export const AskUserQuestionMessage: React.FC<AskUserQuestionMessageProps> = ({
   toolUseBlock,
   resultBlock,
@@ -57,7 +50,7 @@ export const AskUserQuestionMessage: React.FC<AskUserQuestionMessageProps> = ({
   isNewest = false,
 }) => {
   const questions = parseQuestions(toolUseBlock.input);
-  const alreadyAnswered = hasResult(resultBlock);
+  const alreadyAnswered = hasToolResult(resultBlock);
   const formattedTime = formatTimestamp(timestamp);
   const isMultiQuestion = questions.length > 1;
 

components/frontend/src/components/session/permission-request.tsx

@@ -0,0 +1,171 @@
+"use client";
+
+import React, { useState } from "react";
+import { cn } from "@/lib/utils";
+import { Button } from "@/components/ui/button";
+import { ShieldCheck, ShieldX, ShieldAlert } from "lucide-react";
+import { formatTimestamp } from "@/lib/format-timestamp";
+import {
+  hasToolResult,
+  type ToolUseBlock,
+  type ToolResultBlock,
+  type PermissionRequestInput,
+} from "@/types/agentic-session";
+
+export type PermissionRequestMessageProps = {
+  toolUseBlock: ToolUseBlock;
+  resultBlock?: ToolResultBlock;
+  timestamp?: string;
+  onSubmitAnswer?: (formattedAnswer: string) => Promise<void>;
+  isNewest?: boolean;
+};
+
+function isPermissionRequestInput(
+  input: Record<string, unknown>
+): input is PermissionRequestInput {
+  return "tool_name" in input && "key" in input;
+}
+
+type PermissionStatus = "pending" | "approved" | "denied";
+
+function deriveStatus(resultBlock?: ToolResultBlock): PermissionStatus {
+  if (!hasToolResult(resultBlock)) return "pending";
+  const content = resultBlock?.content;
+  if (typeof content !== "string") return "denied";
+  try {
+    return JSON.parse(content).approved === true ? "approved" : "denied";
+  } catch {
+    return "denied";
+  }
+}
+
+const STATUS_CONFIG: Record<PermissionStatus, {
+  icon: typeof ShieldCheck;
+  avatarClass: string;
+  borderClass: string;
+}> = {
+  pending: {
+    icon: ShieldAlert,
+    avatarClass: "bg-amber-500",
+    borderClass: "border-l-amber-500 bg-amber-50/30 dark:bg-amber-950/10",
+  },
+  approved: {
+    icon: ShieldCheck,
+    avatarClass: "bg-green-600",
+    borderClass: "border-l-green-500 bg-green-50/30 dark:bg-green-950/10",
+  },
+  denied: {
+    icon: ShieldX,
+    avatarClass: "bg-red-600",
+    borderClass: "border-l-red-500 bg-red-50/30 dark:bg-red-950/10",
+  },
+};
+
+export const PermissionRequestMessage: React.FC<
+  PermissionRequestMessageProps
+> = ({ toolUseBlock, resultBlock, timestamp, onSubmitAnswer, isNewest = false }) => {
+  const input = toolUseBlock.input;
+  const status = deriveStatus(resultBlock);
+  const formattedTime = formatTimestamp(timestamp);
+
+  const [submitted, setSubmitted] = useState(false);
+  const [isSubmitting, setIsSubmitting] = useState(false);
+  const disabled = status !== "pending" || submitted || isSubmitting || !isNewest;
+
+  if (!isPermissionRequestInput(input)) return null;
+
+  const handleResponse = async (allow: boolean) => {
+    if (!onSubmitAnswer || disabled) return;
+
+    const response = JSON.stringify({
+      approved: allow,
+      tool_name: input.tool_name,
+      key: input.key,
+    });
+
+    try {
+      setIsSubmitting(true);
+      await onSubmitAnswer(response);
+      setSubmitted(true);
+    } finally {
+      setIsSubmitting(false);
+    }
+  };
+
+  const activeConfig = STATUS_CONFIG[disabled && status !== "pending" ? status : "pending"];
+  const Icon = activeConfig.icon;
+
+  return (
+    <div className="mb-3">
+      <div className="flex items-start gap-3">
+        <div className="flex-shrink-0">
+          <div
+            className={cn(
+              "w-8 h-8 rounded-full flex items-center justify-center",
+              activeConfig.avatarClass
+            )}
+          >
+            <Icon className="w-4 h-4 text-white" />
+          </div>
+        </div>
+
+        <div className="flex-1 min-w-0">
+          {formattedTime && (
+            <div className="text-[10px] text-muted-foreground/60 mb-0.5">
+              {formattedTime}
+            </div>
+          )}
+
+          <div
+            className={cn("rounded-lg border-l-3 pl-3 pr-3 py-2.5", activeConfig.borderClass)}
+          >
+            <p className="text-sm font-medium text-foreground mb-1">
+              Permission Required
+            </p>
+            <p className="text-sm text-foreground/80 mb-2">
+              {input.description}
+            </p>
+
+            {(input.file_path || input.command) && (
+              <div className="text-xs text-muted-foreground font-mono bg-muted/50 rounded px-2 py-1 mb-2 break-all">
+                {input.file_path || input.command}
+              </div>
+            )}
+
+            {disabled && status !== "pending" && (
+              <p className="text-xs text-muted-foreground">
+                {status === "approved" ? "Approved" : "Denied"}
+              </p>
+            )}
+
+            {!disabled && (
+              <div className="flex items-center gap-2 mt-2 pt-1.5 border-t border-border/40">
+                <Button
+                  size="sm"
+                  className="h-7 text-xs gap-1 px-3 bg-green-600 hover:bg-green-700 text-white"
+                  onClick={() => handleResponse(true)}
+                  disabled={isSubmitting}
+                >
+                  <ShieldCheck className="w-3 h-3" />
+                  Allow
+                </Button>
+                <Button
+                  size="sm"
+                  variant="outline"
+                  className="h-7 text-xs gap-1 px-3 text-red-600 border-red-200 hover:bg-red-50 dark:border-red-800 dark:hover:bg-red-950/30"
+                  onClick={() => handleResponse(false)}
+                  disabled={isSubmitting}
+                >
+                  <ShieldX className="w-3 h-3" />
+                  Deny
+                </Button>
+              </div>
+            )}
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+PermissionRequestMessage.displayName = "PermissionRequestMessage";

components/frontend/src/components/ui/stream-message.tsx

@@ -5,6 +5,7 @@ import { MessageObject, ToolUseMessages, HierarchicalToolMessage } from "@/types
 import { LoadingDots, Message } from "@/components/ui/message";
 import { ToolMessage } from "@/components/ui/tool-message";
 import { AskUserQuestionMessage } from "@/components/session/ask-user-question";
+import { PermissionRequestMessage } from "@/components/session/permission-request";
 import { ThinkingMessage } from "@/components/ui/thinking-message";
 import { SystemMessage } from "@/components/ui/system-message";
 import { Button } from "@/components/ui/button";
@@ -20,9 +21,16 @@ export type StreamMessageProps = {
   currentUserId?: string;
 };
 
+function normalizeToolName(name: string): string {
+  return name.toLowerCase().replace(/[^a-z]/g, "");
+}
+
 function isAskUserQuestionTool(name: string): boolean {
-  const normalized = name.toLowerCase().replace(/[^a-z]/g, "");
-  return normalized === "askuserquestion";
+  return normalizeToolName(name) === "askuserquestion";
+}
+
+function isPermissionRequestTool(name: string): boolean {
+  return normalizeToolName(name) === "permissionrequest";
 }
 
 const getRandomAgentMessage = () => {
@@ -59,6 +67,19 @@ export const StreamMessage: React.FC<StreamMessageProps> = ({ message, onGoToRes
       );
     }
 
+    // Render PermissionRequest with Allow/Deny buttons
+    if (isPermissionRequestTool(message.toolUseBlock.name)) {
+      return (
+        <PermissionRequestMessage
+          toolUseBlock={message.toolUseBlock}
+          resultBlock={message.resultBlock}
+          timestamp={message.timestamp}
+          onSubmitAnswer={onSubmitAnswer}
+          isNewest={isNewest}
+        />
+      );
+    }
+
     // Check if this is a hierarchical message with children
     const hierarchical = message as HierarchicalToolMessage;
     return (

components/frontend/src/hooks/use-agent-status.ts

@@ -5,9 +5,13 @@ import type {
 } from "@/types/agentic-session";
 import type { PlatformMessage } from "@/types/agui";
 
-function isAskUserQuestionTool(name: string): boolean {
-  const normalized = name.toLowerCase().replace(/[^a-z]/g, "");
-  return normalized === "askuserquestion";
+function normalizeToolName(name: string): string {
+  return name.toLowerCase().replace(/[^a-z]/g, "");
+}
+
+function isHumanInTheLoopTool(name: string): boolean {
+  const normalized = normalizeToolName(name);
+  return normalized === "askuserquestion" || normalized === "permissionrequest";
 }
 
 /**
@@ -38,7 +42,7 @@ export function useAgentStatus(
 
       // Check the last tool call on this message
       const lastTc = msg.toolCalls[msg.toolCalls.length - 1];
-      if (lastTc.function?.name && isAskUserQuestionTool(lastTc.function.name)) {
+      if (lastTc.function?.name && isHumanInTheLoopTool(lastTc.function.name)) {
         const hasResult =
           lastTc.result !== undefined &&
           lastTc.result !== null &&

components/frontend/src/types/agentic-session.ts

@@ -31,6 +31,15 @@ export type AskUserQuestionInput = {
 	questions: AskUserQuestionItem[];
 };
 
+// PermissionRequest tool types (synthetic tool emitted by can_use_tool callback)
+export type PermissionRequestInput = {
+	tool_name: string;
+	file_path?: string;
+	command?: string;
+	description: string;
+	key: string;
+};
+
 export type LLMSettings = {
 	model: string;
 	temperature: number;
@@ -132,6 +141,15 @@ export type ToolResultBlock = {
 
 export type ContentBlock = TextBlock | ReasoningBlock | ToolUseBlock | ToolResultBlock;
 
+/** Check whether a ToolResultBlock contains a non-empty result. */
+export function hasToolResult(resultBlock?: ToolResultBlock): boolean {
+	if (!resultBlock) return false;
+	const content = resultBlock.content;
+	if (!content) return false;
+	if (typeof content === "string" && content.trim() === "") return false;
+	return true;
+}
+
 export type ToolUseMessages = {
 	type: "tool_use_messages";
 	toolUseBlock: ToolUseBlock;