AI Travel Agent

1declare global {
2  namespace NodeJS {
3    interface ProcessEnv {
4      USER_APIFY_TOKEN: string;
5      LANGSMITH_TRACING: string;
6      LANGSMITH_ENDPOINT: string;
7      LANGSMITH_API_KEY: string;
8      LANGSMITH_PROJECT: string;
9      OPENAI_API_KEY: string;
10      ZIP_API_KEY: string;
11      NODE_ENV: 'development' | 'production';
12    }
13  }
14}
15
16// If this file has no import/export statements (i.e. is a script)
17// convert it into a module by adding an empty export statement.
18export {}

1import dotenv from 'dotenv';
2import { Actor, ApifyClient, log } from 'apify';
3import { StateGraph, StateGraphArgs, START, END } from '@langchain/langgraph';
4import LocationAgent from './agents/location.js';
5import DeciderAgent from './agents/decider.js';
6import ResearcherAgent from './agents/researcher.js';
7import SuccessAgent from './agents/success.js';
8import { chargeForActorStart } from './utils/ppe_handler.js';
9
10// if available, .env variables are loaded
11dotenv.config();
12
13/**
14 * Actor input schema
15 */
16type Input = {
17  instructions: string;
18  modelName?: string;
19  openaiApiKey?: string;
20  debug?: boolean;
21}
22
23/**
24 * Actor initialization code and initial charge
25*/
26await Actor.init();
27await chargeForActorStart();
28
29// Handle and validate input
30const {
31  instructions,
32  modelName = 'gpt-4o-mini',
33  openaiApiKey,
34  debug,
35} = await Actor.getInput() as Input;
36if (debug) {
37  log.setLevel(log.LEVELS.DEBUG);
38} else {
39  log.setLevel(log.LEVELS.INFO);
40}
41// if available, the Actor uses the user's openaiApiKey. Otherwise it charges for use.
42const tokenCostActive = (openaiApiKey ?? '').length === 0;
43if (tokenCostActive) {
44  log.info("No openaiApiKey was detected. You'll be charged for token usage.");
45} else {
46  log.info("Env openaiApiKey detected. You won't be charged for token usage.");
47}
48if (!instructions) {
49  throw new Error('Instructions are required. Create an INPUT.json file in the `storage/key_value_stores/default` folder and add the respective keys.');
50}
51
52// Apify is used to call tools and manage datasets
53const userToken = process.env.USER_APIFY_TOKEN;
54if (!userToken) {
55  throw new Error('User token is required. Export your Apify secret as USER_APIFY_TOKEN.');
56}
57const apifyClient = new ApifyClient({
58  token: userToken,
59});
60
61/**
62 * LangGraph StateGraph schema
63 */
64type StateSchema = {
65  instructions: string;
66  bestLocations: string;
67  datasetId: string;
68  totalItems: number;
69  assumptions: string;
70  itemsChecked: number;
71  recommendations: string[];
72  output: string;
73}
74
75const graphState: StateGraphArgs<StateSchema>['channels'] = {
76  instructions: {
77    value: (x?: string, y?: string) => y ?? x ?? '',
78    default: () => instructions,
79  },
80  bestLocations: {
81    value: (x?: string, y?: string) => y ?? x ?? '',
82    default: () => '',
83  },
84  datasetId: {
85    value: (x?: string, y?: string) => y ?? x ?? '',
86    default: () => '',
87  },
88  totalItems: {
89    value: (x?: number, y?: number) => y ?? x ?? 0,
90    default: () => 0,
91  },
92  assumptions: {
93    value: (x?: string, y?: string) => y ?? x ?? '',
94    default: () => '',
95  },
96  itemsChecked: {
97    value: (x?: number, y?: number) => y ?? x ?? 0,
98    default: () => 0,
99  },
100  recommendations: {
101    value: (x?: string[], y?: string[]) => y ?? x ?? [],
102    default: () => [],
103  },
104  output: {
105    value: (x?: string, y?: string) => y ?? x ?? '',
106    default: () => '',
107  },
108};
109
110async function locationNode(state: StateSchema) {
111  const locationAgent = new LocationAgent({
112    apifyClient,
113    modelName,
114    openaiApiKey: openaiApiKey ?? process.env.OPENAI_API_KEY,
115    log,
116  });
117  const { agentExecutor, costHandler } = locationAgent;
118  const response = await agentExecutor.invoke({ input: state.instructions });
119  log.debug(`locationAgent 🤖 : ${response.output}`);
120  await costHandler.logOrChargeForTokens(modelName, tokenCostActive);
121  return { bestLocations: response.output };
122}
123
124async function researcherNode(state: StateSchema) {
125  const researcherAgent = new ResearcherAgent({
126    apifyClient,
127    modelName,
128    openaiApiKey: openaiApiKey ?? process.env.OPENAI_API_KEY,
129    log,
130  });
131  const { agentExecutor, costHandler } = researcherAgent;
132  const input = 'The user asked sent this exact query:\n\n'
133    + `'${state.instructions}'\n\n`
134    + 'You asked someone for help to get the best locations in that city and country. '
135    + 'The answer you received was this:\n\n'
136    + `'${state.bestLocations}'\n\n`
137    + 'Please make some research to gather information to be able to answer the user accordingly.';
138  const response = await agentExecutor.invoke({ input });
139  log.debug(`researcherAgent 🤖 : ${response.output}`);
140  const { datasetId, totalItems, assumptions } = JSON.parse(response.output);
141  await costHandler.logOrChargeForTokens(modelName, tokenCostActive);
142  return { datasetId, totalItems, assumptions };
143}
144
145async function deciderNode(state: StateSchema) {
146  const deciderAgent = new DeciderAgent({
147    apifyClient,
148    modelName,
149    openaiApiKey: openaiApiKey ?? process.env.OPENAI_API_KEY,
150    log,
151  });
152  const { agentExecutor, costHandler } = deciderAgent;
153  const input = 'The user asked sent this exact query:\n\n'
154    + `'${state.instructions}'\n\n`
155    + 'You asked someone for help to get the best locations in that city and country. '
156    + 'The answer you received was this:\n\n'
157    + `'${state.bestLocations}'\n\n`
158    + 'You asked someone else for help to get the best places to stay in in those locations using Airbnb. '
159    + 'The answer you received was this:\n\n'
160    + `Airbnb Apify dataset ID: '${state.datasetId}'\n`
161    + `Total items in Airbnb dataset: '${state.totalItems}'\n`
162    + `Assumptions made when cretating the Airbnb dataset:: '${state.assumptions}'\n`
163    + `Total results already checked in Airbnb dataset: itemsChecked='${state.itemsChecked}'\n\n`
164    + 'Please explore theavailable datasets for the best results.';
165  const response = await agentExecutor.invoke({ input });
166  log.debug(`deciderAgent 🤖 : ${response.output}`);
167  const { itemsChecked, recommendations } = JSON.parse(response.output);
168  await costHandler.logOrChargeForTokens(modelName, tokenCostActive);
169  return {
170    itemsChecked: state.itemsChecked + itemsChecked,
171    recommendations: [...state.recommendations, ...recommendations]
172  };
173}
174
175const resultsCheckedRouter = (state: StateSchema) => {
176  const allResultsChecked = state.itemsChecked >= state.totalItems;
177  log.debug(`allResultsChecked: ${allResultsChecked}`);
178  const thousandResultsChecked = state.itemsChecked > 1000;
179  log.debug(`thousandResultsChecked: ${thousandResultsChecked}`);
180  const fifteenRecommendationsFound = state.recommendations.length > 15;
181  log.debug(`fifteenRecommendationsFound: ${fifteenRecommendationsFound}`);
182  if (
183    allResultsChecked
184    || thousandResultsChecked
185    || fifteenRecommendationsFound
186  ) {
187    // if any of the above criteria are met, it passes the ball to the successAgent
188    return 'success';
189  }
190  // if none of the above criteria are met, it runs the same node again
191  return 'decider';
192};
193
194async function successNode(state: StateSchema) {
195  const successAgent = new SuccessAgent({
196    apifyClient,
197    modelName,
198    openaiApiKey: openaiApiKey ?? process.env.OPENAI_API_KEY,
199    log,
200  });
201  const { agentExecutor, costHandler } = successAgent;
202  const input = 'The user asked sent this exact query:\n\n'
203    + `'${state.instructions}'\n\n`
204    + 'You asked someone for help to get the best locations in that city and state. '
205    + 'The answer you received was this:\n\n'
206    + `'${state.bestLocations}'\n\n`
207    + 'You asked someone else for help to get the best places to stay in those locations using Airbnb and their expert jugdgement. '
208    + 'The answer you received was this:\n\n'
209    + `Assumptions made when searching Airbnb: '${state.assumptions}'\n\n`
210    + `Total places to stay checked: '${state.itemsChecked}'\n`
211    + `Total places to stay recommended: '${state.recommendations.length}'\n`
212    + `Best places to stay in stringified JSON format: '${JSON.stringify(state.recommendations)}'\n`
213    + 'Please select the top 5 places to stay and answer the user explaining the whole process in markdown format.';
214  const response = await agentExecutor.invoke({ input });
215  log.debug(`successNode 🤖 : ${response.output}`);
216  await costHandler.logOrChargeForTokens(modelName, tokenCostActive);
217  return { output: response.output };
218}
219
220const graph = new StateGraph({ channels: graphState })
221  .addNode('location', locationNode)
222  .addNode('researcher', researcherNode)
223  .addNode('decider', deciderNode)
224  .addNode('success', successNode)
225  .addEdge(START, 'location')
226  .addEdge('location', 'researcher')
227  .addEdge('researcher', 'decider')
228  .addConditionalEdges('decider', resultsCheckedRouter)
229  .addEdge('success', END);
230
231const runnable = graph.compile();
232
233const response = await runnable.invoke(
234  { input: instructions },
235  { configurable: { thread_id: 42 } }, // this line shows that the agent can be thread-aware
236);
237
238log.debug(`Agent 🤖 : ${response.output}`);
239
240await Actor.pushData({
241  actorName: 'AI Travel Agent',
242  response: response.output,
243});
244
245await Actor.exit();

1import { Log, ApifyClient } from 'apify';
2import { ChatPromptTemplate } from '@langchain/core/prompts';
3import { createToolCallingAgent, AgentExecutor } from 'langchain/agents';
4import { ChatOpenAI } from '@langchain/openai';
5import { StructuredToolInterface } from '@langchain/core/tools';
6import DatasetExplorer from '../tools/dataset_explorer.js';
7import { CostHandler } from '../utils/cost_handler.js';
8
9/**
10 * Interface for parameters required by PropertyAgent class.
11 */
12export interface PropertyAgentParams {
13  apifyClient: ApifyClient,
14  modelName: string,
15  openaiApiKey: string,
16  log: Log | Console;
17}
18
19/**
20 * An AI Agent that explores an Apify dataset in search for the perfect results.
21 */
22export class PropertyAgent {
23  protected log: Log | Console;
24  protected apifyClient: ApifyClient;
25  public agentExecutor: AgentExecutor;
26  public costHandler: CostHandler;
27
28  constructor(fields?: PropertyAgentParams) {
29    this.log = fields?.log ?? console;
30    this.apifyClient = fields?.apifyClient ?? new ApifyClient();
31    this.costHandler = new CostHandler(fields?.modelName ?? 'gpt-4o-mini', this.log);
32    const llm = new ChatOpenAI({
33      model: fields?.modelName,
34      apiKey: fields?.openaiApiKey,
35      temperature: 0,
36      callbacks: [
37        this.costHandler,
38      ],
39    });
40    const tools = this.buildTools(this.apifyClient, this.log);
41    const prompt = this.buildPrompt();
42    const agent = createToolCallingAgent({
43      llm,
44      tools,
45      prompt,
46    });
47    this.agentExecutor = new AgentExecutor({
48      agent,
49      tools,
50      verbose: false,
51      maxIterations: 5,
52    });
53  }
54
55  protected buildTools(
56    apifyClient: ApifyClient, log: Log | Console
57  ): StructuredToolInterface[] {
58    // Tools are initialized to be passed to the agent
59    const datasetExplorer = new DatasetExplorer({ apifyClient, log });
60    return [
61      datasetExplorer,
62    ];
63  }
64
65  protected buildPrompt(): ChatPromptTemplate {
66    return ChatPromptTemplate.fromMessages([
67      ['system',
68        'You are a experienced travel agent that wants to help the user plan the perfect trip. '
69        + "You'll have a datasetId and the total amount of items available to explore. "
70        + 'Explore only one batch of 25 results (using limit=25). '
71        + 'Skip the first items based on the number of items that were already checked (using offset=itemsChecked). '
72        + "When exploring the dataset, include only these fields exactly as written here: ['id','name','title','rating','pricing','url','images']"
73        + 'Remember: do not call the DatasetExplorer tool more than once, or you will die. \n\n'
74        + 'The user may have specified other requests like pets, bedrooms, beds, baths, etc. '
75        + 'Filter the results based on this information or notify the user if you are unable to do so. '
76        + 'Use your expertise to recommend the best results that you can find that matches the user criteria. '
77        + 'If the total amount of items (totalItems) is over 100, select up to 2 results otherwise pick up to 3. Try to at least pick one. '
78        + "As your response, return only a JSON object (and nothing more! not even a ```json or ``` wrapper) with the key 'itemsChecked' as a number with the amount of results that you received from the dataset_explorer and the key 'recommendations' with your recommendations in JSON format, using the same fields that you specified when calling the dataset_explorer."
79      ],
80      ['placeholder', '{chat_history}'],
81      ['human', '{input}'],
82      ['placeholder', '{agent_scratchpad}'],
83    ]);
84  }
85}
86
87export default PropertyAgent;

1import { Log, ApifyClient } from 'apify';
2import { ChatPromptTemplate } from '@langchain/core/prompts';
3import { createToolCallingAgent, AgentExecutor } from 'langchain/agents';
4import { ChatOpenAI } from '@langchain/openai';
5import { StructuredToolInterface } from '@langchain/core/tools';
6import DuckDuckGo from '../tools/duck_duck_go.js';
7import WebsiteScraper from '../tools/website_scraper.js';
8import { CostHandler } from '../utils/cost_handler.js';
9
10/**
11 * Interface for parameters required by LocationAgent class.
12 */
13export interface LocationAgentParams {
14  apifyClient: ApifyClient,
15  modelName: string,
16  openaiApiKey: string,
17  log: Log | Console;
18}
19
20/**
21 * AI Agent that takes the user input and finds the best Zip Codes in a city to live in.
22 */
23export class LocationAgent {
24  protected log: Log | Console;
25  protected apifyClient: ApifyClient;
26  public agentExecutor: AgentExecutor;
27  public costHandler: CostHandler;
28
29  constructor(fields?: LocationAgentParams) {
30    this.log = fields?.log ?? console;
31    this.apifyClient = fields?.apifyClient ?? new ApifyClient();
32    this.costHandler = new CostHandler(fields?.modelName ?? 'gpt-4o-mini', this.log);
33    const llm = new ChatOpenAI({
34      model: fields?.modelName,
35      apiKey: fields?.openaiApiKey,
36      temperature: 0,
37      callbacks: [
38        this.costHandler,
39      ],
40    });
41    const tools = this.buildTools(this.apifyClient, this.log);
42    const prompt = this.buildPrompt();
43    const agent = createToolCallingAgent({
44      llm,
45      tools,
46      prompt,
47    });
48    this.agentExecutor = new AgentExecutor({
49      agent,
50      tools,
51      verbose: false,
52      maxIterations: 5,
53    });
54  }
55
56  protected buildTools(
57    apifyClient: ApifyClient, log: Log | Console
58  ): StructuredToolInterface[] {
59    // Tools are initialized to be passed to the agent
60    const duckDuckGo = new DuckDuckGo({ apifyClient, log });
61    const websiteScraper = new WebsiteScraper({ apifyClient, log });
62    return [
63      duckDuckGo,
64      websiteScraper,
65    ];
66  }
67
68  protected buildPrompt(): ChatPromptTemplate {
69    return ChatPromptTemplate.fromMessages([
70      ['system',
71        'You are a experienced travel agent that wants to help the user plan their trip. '
72        + "You will stick to the following steps, ignoring the specifics of the user's query and focusing only on finding the best locations. "
73        + 'Step 1. The user will ask you for advice regarding traveling to a specific city in the world or even a neighborhood in a city. '
74        + "You don't care where the user lives, since you are not in charge of flights. "
75        + 'If the user does not specify a budget, select mid range (and not low budget or luxury). '
76        + 'If the user does not provide a country, try to guess to which country the city belongs to. '
77        + 'If from the input you cannot get a city and a country or you think that the specified city should not be visited by tourists, '
78        + 'end the conversation and help the user with the input. '
79        // 2. Fetch best neighborhoods to stay at using DuckDuckGo
80        + 'Step 2. With the city and state in hand, use DuckDuckGo replacing the following query: '
81        + "'where to stay and where not to stay in [city], [country]'. "
82        + 'If there the results, use a website scraper on the URLs you think will show you this information. '
83        + 'Iterate until you find the best 3 locations or neighborhoods in the selected city. '
84        + "For best performance when using the website scraper, you can use method='getBestPlacesToStay' and output=null'. "
85        + 'Instead of answering the original question, just return the top 3 locations or neighborhoods and explain to the user why you selected those locations or neighborhoods. \n'
86      ],
87      ['placeholder', '{chat_history}'],
88      ['human', '{input}'],
89      ['placeholder', '{agent_scratchpad}'],
90    ]);
91  }
92}
93
94export default LocationAgent;

1import { Log, ApifyClient } from 'apify';
2import { ChatPromptTemplate } from '@langchain/core/prompts';
3import { createToolCallingAgent, AgentExecutor } from 'langchain/agents';
4import { ChatOpenAI } from '@langchain/openai';
5import { StructuredToolInterface } from '@langchain/core/tools';
6import AirbnbSearch from '../tools/airbnb_search.js';
7import { CostHandler } from '../utils/cost_handler.js';
8
9/**
10 * Interface for parameters required by ResearcherAgent class.
11 */
12export interface ResearcherAgentParams {
13  apifyClient: ApifyClient,
14  modelName: string,
15  openaiApiKey: string,
16  log: Log | Console;
17}
18
19/**
20 * An AI Agent that searches Researcher for specific locations and stores the results in a dataset.
21 */
22export class ResearcherAgent {
23  protected log: Log | Console;
24  protected apifyClient: ApifyClient;
25  public agentExecutor: AgentExecutor;
26  public costHandler: CostHandler;
27
28  constructor(fields?: ResearcherAgentParams) {
29    this.log = fields?.log ?? console;
30    this.apifyClient = fields?.apifyClient ?? new ApifyClient();
31    this.costHandler = new CostHandler(fields?.modelName ?? 'gpt-4o-mini', this.log);
32    const llm = new ChatOpenAI({
33      model: fields?.modelName,
34      apiKey: fields?.openaiApiKey,
35      temperature: 0,
36      callbacks: [
37        this.costHandler,
38      ],
39    });
40    const tools = this.buildTools(this.apifyClient, this.log);
41    const prompt = this.buildPrompt();
42    const agent = createToolCallingAgent({
43      llm,
44      tools,
45      prompt,
46    });
47    this.agentExecutor = new AgentExecutor({
48      agent,
49      tools,
50      verbose: false,
51      maxIterations: 3,
52    });
53  }
54
55  protected buildTools(
56    apifyClient: ApifyClient, log: Log | Console
57  ): StructuredToolInterface[] {
58    // Tools are initialized to be passed to the agent
59    const airbnbSearch = new AirbnbSearch({ apifyClient, log });
60    return [
61      airbnbSearch,
62    ];
63  }
64
65  protected buildPrompt(): ChatPromptTemplate {
66    const today = new Date().toISOString().slice(0, 10);
67    return ChatPromptTemplate.fromMessages([
68      ['system',
69        'You are a experienced travel agent that knows that Airbnb is a website where you can search for places to stay based on criteria like location, dates and price. '
70        + 'Using the recommended locations, search on Airbnb for places that match the user price, date and travelers (adults, children and pets) requirements. '
71        + 'The user must specify who is traveling (adults, children, infants, pets) (default to 2 adults if the information is not given). '
72        + `When managing dates, you always try to use the best format in the world, which is: yyy-mm-dd. For any calculation assume that today is ${today}.`
73        + 'The user can specify if the travel has a start date (default to a trip of one week if the information is not given and choose today if no start date is available). '
74        + 'The user can specify if the travel has an end date (default to a trip of one week if the information is not given and choose today if no start date is available). '
75        + 'The user can specify if the travel destination has a minimum value (default to 1 if the information is not given). '
76        + 'The user can specify if the travel destination has a maximum value (default to 250 if the information is not given). '
77        + 'The user can specify a minimum number of baths, beds or bedrooms (omit these search parameters if the information is not given). '
78        + 'Inform the user of the assumptions you made to make the Airbnb search.'
79        + 'Inform the user the datasetId and the amount of items you received from the airbnb_search tool in order to explore the results later. '
80        + "As your response, return only a JSON object (and nothing more! not even a ```json or ``` wrapper) with the keys 'datasetId' and 'assumptions', with their corresponding values in string format, along with the key 'totalItems' with the number of items in the dataset in number format."
81      ],
82      ['placeholder', '{chat_history}'],
83      ['human', '{input}'],
84      ['placeholder', '{agent_scratchpad}'],
85    ]);
86  }
87}
88
89export default ResearcherAgent;

1import { Log, ApifyClient } from 'apify';
2import { ChatPromptTemplate } from '@langchain/core/prompts';
3import { createToolCallingAgent, AgentExecutor } from 'langchain/agents';
4import { ChatOpenAI } from '@langchain/openai';
5import { StructuredToolInterface } from '@langchain/core/tools';
6import { CostHandler } from '../utils/cost_handler.js';
7
8/**
9 * Interface for parameters required by SuccessAgent class.
10 */
11export interface SuccessAgentParams {
12  apifyClient: ApifyClient,
13  modelName: string,
14  openaiApiKey: string,
15  log: Log | Console;
16}
17
18/**
19 * An AI Agent summarizes the efforts of all agents to answer the users's question.
20 */
21export class SuccessAgent {
22  protected log: Log | Console;
23  protected apifyClient: ApifyClient;
24  public agentExecutor: AgentExecutor;
25  public costHandler: CostHandler;
26
27  constructor(fields?: SuccessAgentParams) {
28    this.log = fields?.log ?? console;
29    this.apifyClient = fields?.apifyClient ?? new ApifyClient();
30    this.costHandler = new CostHandler(fields?.modelName ?? 'gpt-4o-mini', this.log);
31    const llm = new ChatOpenAI({
32      model: fields?.modelName,
33      apiKey: fields?.openaiApiKey,
34      temperature: 0,
35      callbacks: [
36        this.costHandler,
37      ],
38    });
39    const tools = this.buildTools();
40    const prompt = this.buildPrompt();
41    const agent = createToolCallingAgent({
42      llm,
43      tools,
44      prompt,
45    });
46    this.agentExecutor = new AgentExecutor({
47      agent,
48      tools,
49      verbose: false,
50      maxIterations: 3,
51    });
52  }
53
54  protected buildTools(): StructuredToolInterface[] {
55    // Tools are initialized to be passed to the agent
56    return [];
57  }
58
59  protected buildPrompt(): ChatPromptTemplate {
60    return ChatPromptTemplate.fromMessages([
61      ['system',
62        'You are a experienced travel agent that wants to help the user plan the perfect trip. '
63        + 'You asked some colleagues for help and they sent you a bunch of info to help the user.'
64        + 'The user may have specified other requests like pets, bedrooms, beds, baths, gym, etc so make sure to mention them. '
65        + 'Make sure that you show the rating, price, image, description, amenities (or other useful information) and a link to view more information about the chosen results. '
66        + 'If more than one location was specified in the search, try to make it so that your recommendations include results in every one of them. '
67        + 'Please explain why you chose those results and how many you explored before making your choice. '
68      ],
69      ['placeholder', '{chat_history}'],
70      ['human', '{input}'],
71      ['placeholder', '{agent_scratchpad}'],
72    ]);
73  }
74}
75
76export default SuccessAgent;