Add timezone support to tool prompts for localized time context

src/lib/server/textGeneration/mcp/runMcpFlow.ts

@@ -289,7 +289,8 @@ export async function* runMcpFlow({
 			imageProcessor,
 			mmEnabled
 		);
-		const toolPreprompt = buildToolPreprompt(oaTools);
+		const userTimezone = (locals as unknown as { timezone?: string })?.timezone;
+		const toolPreprompt = buildToolPreprompt(oaTools, userTimezone);
 		const prepromptPieces: string[] = [];
 		if (toolPreprompt.trim().length > 0) {
 			prepromptPieces.push(toolPreprompt);

src/lib/server/textGeneration/utils/toolPrompt.ts

@@ -1,19 +1,31 @@
 import type { OpenAiTool } from "$lib/server/mcp/tools";
 
-export function buildToolPreprompt(tools: OpenAiTool[]): string {
+export function buildToolPreprompt(tools: OpenAiTool[], timezone?: string): string {
 	if (!Array.isArray(tools) || tools.length === 0) return "";
 	const names = tools
 		.map((t) => (t?.function?.name ? String(t.function.name) : ""))
 		.filter((s) => s.length > 0);
 	if (names.length === 0) return "";
-	const currentDate = new Date().toLocaleDateString("en-US", {
+
+	const now = new Date();
+	const dateTimeOptions: Intl.DateTimeFormatOptions = {
 		year: "numeric",
 		month: "long",
 		day: "numeric",
-	});
+		weekday: "long",
+		hour: "2-digit",
+		minute: "2-digit",
+		...(timezone ? { timeZone: timezone } : {}),
+	};
+	const currentDateTime = now.toLocaleString("en-US", dateTimeOptions);
+
+	// Build a user-location hint from the IANA timezone (e.g. "America/New_York" → "America/New_York")
+	const locationLine = timezone ? ` User's timezone: ${timezone}.` : "";
+
 	return [
-		`You can use the following tools if helpful: ${names.join(", ")}.`,
-		`Today's date: ${currentDate}.`,
+		`You have access to these tools: ${names.join(", ")}.`,
+		`Current date and time: ${currentDateTime}.${locationLine}`,
+		`Only use a tool if you cannot answer without it. For simple tasks like writing, editing text, or answering from your knowledge, respond directly without tools.`,
 		`If a tool generates an image, you can inline it directly: ![alt text](image_url).`,
 		`If a tool needs an image, set its image field ("input_image", "image", or "image_url") to a reference like "image_1", "image_2", etc. (ordered by when the user uploaded them).`,
 		`Default to image references; only use a full http(s) URL when the tool description explicitly asks for one, or reuse a URL a previous tool returned.`,

src/lib/utils/messageUpdates.ts

@@ -24,6 +24,8 @@ type MessageUpdateRequestOptions = {
 	selectedMcpServerNames?: string[];
 	// Optional: pass selected MCP server configs (for custom client-defined servers)
 	selectedMcpServers?: Array<{ name: string; url: string; headers?: KeyValuePair[] }>;
+	// User's IANA timezone (e.g. "America/New_York")
+	timezone?: string;
 };
 export async function fetchMessageUpdates(
 	conversationId: string,
@@ -43,6 +45,7 @@ export async function fetchMessageUpdates(
 		// Will be ignored server-side if unsupported
 		selectedMcpServerNames: opts.selectedMcpServerNames,
 		selectedMcpServers: opts.selectedMcpServers,
+		timezone: opts.timezone,
 	});
 
 	opts.files?.forEach((file) => {

src/routes/conversation/[id]/+page.svelte

@@ -226,6 +226,7 @@
 						url: s.url,
 						headers: s.headers,
 					})),
+					timezone: Intl.DateTimeFormat().resolvedOptions().timeZone,
 				},
 				messageUpdatesAbortController.signal
 			).catch((err) => {

src/routes/conversation/[id]/+server.ts

@@ -128,6 +128,7 @@ export async function POST({ request, locals, params, getClientAddress }) {
 		is_retry: isRetry,
 		selectedMcpServerNames,
 		selectedMcpServers,
+		timezone,
 	} = z
 		.object({
 			id: z.string().uuid().refine(isMessageId).optional(), // parent message id to append to for a normal message, or the message id for a retry/continue
@@ -152,6 +153,7 @@ export async function POST({ request, locals, params, getClientAddress }) {
 					)
 				)
 				.default([]),
+			timezone: z.optional(z.string()),
 			files: z.optional(
 				z.array(
 					z.object({
@@ -182,6 +184,11 @@ export async function POST({ request, locals, params, getClientAddress }) {
 		// ignore attachment errors, pipeline will just use env servers
 	}
 
+	// Attach user timezone so the tool prompt can include localized time
+	if (timezone) {
+		(locals as unknown as Record<string, unknown>).timezone = timezone;
+	}
+
 	const inputFiles = await Promise.all(
 		form
 			.getAll("files")