feat(ms22-p2): add agent selector UI in WebUI (#685)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/web/src/components/chat/AgentSelector.tsx

@@ -0,0 +1,128 @@
+"use client";
+
+import React from "react";
+
+interface AgentSelectorProps {
+  selectedAgent?: string | null;
+  onChange?: (agent: string | null) => void;
+  disabled?: boolean;
+}
+
+const AGENT_CONFIG = {
+  jarvis: {
+    displayName: "Jarvis",
+    role: "Orchestrator",
+    color: "#3498db",
+  },
+  builder: {
+    displayName: "Builder",
+    role: "Coding Agent",
+    color: "#3b82f6",
+  },
+  medic: {
+    displayName: "Medic",
+    role: "Health Monitor",
+    color: "#10b981",
+  },
+} as const;
+
+function JarvisIcon({ className }: { className?: string }): React.ReactElement {
+  return (
+    <svg
+      className={`w-3 h-3 ${className ?? ""}`}
+      viewBox="0 0 24 24"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth="1.5"
+    >
+      <circle cx="12" cy="12" r="3" />
+      <path d="M12 2v4M12 22v-4" />
+      <path d="M2 12h4M22 12h-4" />
+    </svg>
+  );
+}
+
+function BuilderIcon({ className }: { className?: string }): React.ReactElement {
+  return (
+    <svg
+      className={`w-3 h-3 ${className ?? ""}`}
+      viewBox="0 0 24 24"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth="1.5"
+    >
+      <path d="M14.7 6.3a1 1 0 0 0 0 1.4l1.6 1.6a1 1 0 0 0 1.4 0l3.77-3.77a6 6 0 0 1-7.94 7.94l-6.91 6.91a2.12 2.12 0 0 1-3-3l6.91-6.91a6 6 0 0 1 7.94-7.94l-3.76 3.76z" />
+    </svg>
+  );
+}
+
+function MedicIcon({ className }: { className?: string }): React.ReactElement {
+  return (
+    <svg
+      className={`w-3 h-3 ${className ?? ""}`}
+      viewBox="0 0 24 24"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth="1.5"
+    >
+      <path d="M22 12h-4l-3 9L9 3l-3 9H2" />
+    </svg>
+  );
+}
+
+const AGENT_ICONS: Record<string, React.FC<{ className?: string }>> = {
+  jarvis: JarvisIcon,
+  builder: BuilderIcon,
+  medic: MedicIcon,
+};
+
+export function AgentSelector({
+  selectedAgent,
+  onChange,
+  disabled,
+}: AgentSelectorProps): React.ReactElement {
+  return (
+    <div className="flex items-center gap-2">
+      <span className="text-xs font-medium" style={{ color: "rgb(var(--text-muted))" }}>
+        Agent
+      </span>
+
+      <div className="flex flex-wrap gap-1">
+        {Object.entries(AGENT_CONFIG).map(([name, config]) => {
+          const Icon = AGENT_ICONS[name];
+          const isSelected = selectedAgent === name;
+
+          return (
+            <button
+              key={name}
+              type="button"
+              onClick={() => onChange?.(isSelected ? null : name)}
+              disabled={disabled}
+              className={`flex items-center gap-1.5 px-2 py-1.5 rounded-lg border transition-all text-xs ${
+                isSelected ? "border-primary bg-primary/10 shadow-sm" : "hover:bg-muted/50"
+              } ${disabled ? "opacity-50 cursor-not-allowed" : ""}`}
+              style={{
+                borderColor: isSelected
+                  ? "rgb(var(--accent-primary))"
+                  : "rgb(var(--border-default))",
+                color: isSelected ? "rgb(var(--accent-primary))" : "rgb(var(--text-primary))",
+              }}
+              title={`${config.displayName} — ${config.role}`}
+            >
+              <span
+                className="rounded-full"
+                style={{
+                  backgroundColor: config.color,
+                  width: "8px",
+                  height: "8px",
+                }}
+              />
+              {Icon && <Icon />}
+              <span className="font-medium">{config.displayName}</span>
+            </button>
+          );
+        })}
+      </div>
+    </div>
+  );
+}

apps/web/src/components/chat/Chat.tsx

@@ -9,6 +9,7 @@ import { useWorkspaceId } from "@/lib/hooks";
 import { MessageList } from "./MessageList";
 import { ChatInput, type ModelId, DEFAULT_TEMPERATURE, DEFAULT_MAX_TOKENS } from "./ChatInput";
 import { ChatEmptyState } from "./ChatEmptyState";
+import { AgentSelector } from "./AgentSelector";
 import type { Message } from "@/hooks/useChat";
 
 export interface ChatRef {
@@ -66,6 +67,7 @@ export const Chat = forwardRef<ChatRef, ChatProps>(function Chat(
   const [selectedModel, setSelectedModel] = useState<ModelId>("llama3.2");
   const [temperature, setTemperature] = useState<number>(DEFAULT_TEMPERATURE);
   const [maxTokens, setMaxTokens] = useState<number>(DEFAULT_MAX_TOKENS);
+  const [selectedAgent, setSelectedAgent] = useState<string | null>(null);
 
   // Suggestion fill value: controls ChatInput's textarea content
   const [suggestionValue, setSuggestionValue] = useState<string | undefined>(undefined);
@@ -88,6 +90,7 @@ export const Chat = forwardRef<ChatRef, ChatProps>(function Chat(
     temperature,
     maxTokens,
     ...(initialProjectId !== undefined && { projectId: initialProjectId }),
+    ...(selectedAgent !== null && { agent: selectedAgent }),
   });
 
   // Read workspace ID from localStorage (set by auth-context after session check).
@@ -375,6 +378,13 @@ export const Chat = forwardRef<ChatRef, ChatProps>(function Chat(
         }}
       >
         <div className="mx-auto max-w-4xl px-4 py-4 lg:px-8">
+          <div className="mb-3">
+            <AgentSelector
+              selectedAgent={selectedAgent}
+              onChange={setSelectedAgent}
+              disabled={isChatLoading || isStreaming || !user}
+            />
+          </div>
           <ChatInput
             onSend={handleSendMessage}
             disabled={isChatLoading || !user}