import { StructuredTool } from "@langchain/core/tools";
import * as z from "zod";
function compact(text: string, limit: number = 200): string {
const cleaned = text.split(/\s+/).join(" ");
return cleaned.length <= limit
? cleaned
: cleaned.slice(0, limit).split(" ").slice(0, -1).join(" ");
}
async function searchApi(query: string): Promise<string | null> {
const tavilyKey = process.env.TAVILY_API_KEY;
if (!tavilyKey) {
throw new Error(
"TAVILY_API_KEY environment variable is not set. Please set it with: export TAVILY_API_KEY=your-key-here",
);
}
try {
const response = await fetch("https://api.tavily.com/search", {
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({
api_key: tavilyKey,
query: query,
max_results: 3,
search_depth: "basic",
include_answer: true,
}),
});
if (!response.ok) {
throw new Error(
`Tavily API error: ${response.status} ${response.statusText}`,
);
}
const data = (await response.json()) as {
answer?: string;
results?: Array<{ content?: string }>;
};
const answer = data.answer || "";
const snippets = (data.results || []).map((r) => r.content || "").join(" ");
const combined = `${answer} ${snippets}`.trim();
return combined.slice(0, 400) || null;
} catch (error) {
throw error;
}
}
const destinationSchema = z.string().min(1, "Destination is required").max(100);
const durationSchema = z
.string()
.regex(/^\d+\s*days?$/i, "Duration must be like '3 days' or '7 days'");
const interestsSchema = z.string().min(1, "Interests are required").max(200);
class EssentialInfoTool extends StructuredTool {
name = "essential_info";
description =
"Required. Fetches weather, best time to visit, top attractions, and etiquette for a destination. Call this first when building a trip plan. Do not use for budget or local experiences.";
schema = z.object({
destination: destinationSchema.describe(
"The travel destination (e.g., 'Japan', 'Portugal'). Required.",
),
});
async _call({ destination }: { destination: string }): Promise<string> {
const dest = destination.trim();
if (!dest) return "Error: destination is required.";
const query = `${dest} travel essentials weather best time top attractions etiquette`;
const result = await searchApi(query);
if (result) {
return `${dest} essentials: ${compact(result)}`;
}
return `${dest} is a popular travel destination. Expect local culture, cuisine, and landmarks worth exploring.`;
}
}
class BudgetBasicsTool extends StructuredTool {
name = "budget_basics";
description =
"Required. Fetches travel cost breakdown (lodging, food, transport, activities) for a destination and trip duration. Call with the exact duration the user asked for (e.g., '5 days'). Do not use for essentials or local experiences.";
schema = z.object({
destination: destinationSchema.describe(
"The travel destination. Required.",
),
duration: durationSchema.describe(
"Trip duration in the form 'N days' (e.g., '5 days', '7 days'). Required.",
),
});
async _call({
destination,
duration,
}: {
destination: string;
duration: string;
}): Promise<string> {
const dest = destination.trim();
const dur = duration.trim();
if (!dest || !dur) return "Error: destination and duration are required.";
const query = `${dest} travel budget average daily costs ${dur}`;
const result = await searchApi(query);
if (result) {
return `${dest} budget (${dur}): ${compact(result)}`;
}
return `Budget for ${dur} in ${dest} depends on lodging, meals, transport, and attractions.`;
}
}
class LocalFlavorTool extends StructuredTool {
name = "local_flavor";
description =
"Required. Fetches authentic local experiences and cultural highlights for a destination. Call with the user's stated interests (e.g., 'food, culture', 'beaches, wine'). Do not use for essentials or budget.";
schema = z.object({
destination: destinationSchema.describe(
"The travel destination. Required.",
),
interests: interestsSchema.describe(
"The user's interests (e.g., 'food, culture', 'beaches, wine'). Required—use the exact interests from the request.",
),
});
async _call({
destination,
interests,
}: {
destination: string;
interests: string;
}): Promise<string> {
const dest = destination.trim();
const intr = interests.trim() || "local culture";
if (!dest) return "Error: destination is required.";
const query = `${dest} authentic local experiences ${intr}`;
const result = await searchApi(query);
if (result) {
return `${dest} ${intr}: ${compact(result)}`;
}
return `Explore ${dest}'s unique ${intr} through markets, neighborhoods, and local eateries.`;
}
}
export const essentialInfoTool = new EssentialInfoTool();
export const budgetBasicsTool = new BudgetBasicsTool();
export const localFlavorTool = new LocalFlavorTool();
export const travelTools = [
essentialInfoTool,
budgetBasicsTool,
localFlavorTool,
];
