feat(agent): localize date/time in system prompt (#45)

Send the user's IANA timezone (Intl API) as x-timezone header
from the chat transport. The system prompt now formats date
and time in the user's local timezone instead of UTC.

Co-authored-by: Nicholai <nicholaivogelfilms@gmail.com>

src/app/api/agent/route.ts

@@ -37,6 +37,8 @@ export async function POST(req: Request): Promise<Response> {
 
   const currentPage =
     req.headers.get("x-current-page") ?? undefined
+  const timezone =
+    req.headers.get("x-timezone") ?? undefined
 
   const model = await getAgentModel()
 
@@ -46,6 +48,7 @@ export async function POST(req: Request): Promise<Response> {
       userName: user.displayName ?? user.email,
       userRole: user.role,
       currentPage,
+      timezone,
       memories,
       pluginSections,
       mode: "full",

src/hooks/use-compass-chat.ts

@@ -33,7 +33,11 @@ export function useCompassChat(options?: UseCompassChatOptions) {
   const chatState = useChat({
     transport: new DefaultChatTransport({
       api: "/api/agent",
-      headers: { "x-current-page": pathname },
+      headers: {
+        "x-current-page": pathname,
+        "x-timezone":
+          Intl.DateTimeFormat().resolvedOptions().timeZone,
+      },
     }),
     onFinish: options?.onFinish,
     onError: (err) => {

src/lib/agent/system-prompt.ts

@@ -26,6 +26,7 @@ interface PromptContext {
   readonly userRole: string
   readonly currentPage?: string
   readonly memories?: string
+  readonly timezone?: string
   readonly pluginSections?: ReadonlyArray<PromptSection>
   readonly mode?: PromptMode
 }
@@ -216,11 +217,27 @@ function buildUserContext(
   state: DerivedState,
 ): ReadonlyArray<string> {
   if (state.mode === "none") return []
+  const tz = ctx.timezone ?? "UTC"
+  const now = new Date()
+  const date = now.toLocaleDateString("en-US", {
+    weekday: "long",
+    year: "numeric",
+    month: "long",
+    day: "numeric",
+    timeZone: tz,
+  })
+  const time = now.toLocaleTimeString("en-US", {
+    hour: "2-digit",
+    minute: "2-digit",
+    timeZone: tz,
+  })
   return [
     "## User Context",
     `- Name: ${ctx.userName}`,
     `- Role: ${ctx.userRole}`,
     `- Current page: ${state.page}`,
+    `- Current date: ${date}`,
+    `- Current time: ${time} (${tz})`,
   ]
 }