LangGraph.jsとElasticsearchを使用して金融AI検索ワークフローを構築

const VCState = Annotation.Root({
  input: Annotation<string>(), // User's natural language query
  searchStrategy: Annotation<string>(), // Search strategy chosen by LLM
  searchParams: Annotation<any>(), // Prepared search parameters
  results: Annotation<any[]>(), // Search results
  final: Annotation<string>(), // Final formatted response
});

npm init -y

npm install @elastic/elasticsearch @langchain/langgraph @langchain/openai @langchain/core dotenv zod && npm install --save-dev @types/node tsx typescript

ELASTICSEARCH_ENDPOINT="your-endpoint-here"
ELASTICSEARCH_API_KEY="your-key-here"
OPENAI_API_KEY="your-key-here"

import { writeFileSync } from "node:fs";
import { StateGraph, Annotation, START, END } from "@langchain/langgraph";
import { ChatOpenAI } from "@langchain/openai";
import { z } from "zod";
import {
  esClient,
  ingestDocuments,
  createSearchTemplates,
  INDEX_NAME,
  INVESTMENT_FOCUSED_TEMPLATE,
  MARKET_FOCUSED_TEMPLATE,
  createIndex,
} from "./elasticsearchSetup.js";

const llm = new ChatOpenAI({ model: "gpt-4o-mini" });

async function saveGraphImage(app: any): Promise<void> {
  try {
    const drawableGraph = app.getGraph();
    const image = await drawableGraph.drawMermaidPng();
    const arrayBuffer = await image.arrayBuffer();

    const filePath = "./workflow_graph.png";
    writeFileSync(filePath, new Uint8Array(arrayBuffer));
    console.log(`📊 Workflow graph saved as: ${filePath}`);
  } catch (error: any) {
    console.log("⚠️  Could not save graph image:", error.message);
  }
}

async function getAvailableFilters() {
  try {
    const response = await esClient.search({
      index: INDEX_NAME,
      size: 0,
      aggs: {
        industries: {
          terms: { field: "industry", size: 100 },
        },
        locations: {
          terms: { field: "location", size: 100 },
        },
        funding_stages: {
          terms: { field: "funding_stage", size: 20 },
        },
        business_models: {
          terms: { field: "business_model", size: 10 },
        },
        lead_investors: {
          terms: { field: "lead_investor", size: 100 },
        },
        funding_amount_stats: {
          stats: { field: "funding_amount" },
        },
      },
    });

    return response.aggregations;
  } catch (error) {
    console.error("❌ Error getting available filters:", error);
    return {};
  }
}

{
  "industries": {
    "doc_count_error_upper_bound": 0,
    "sum_other_doc_count": 0,
    "buckets": [
      {
        "key": "logistics",
        "doc_count": 5
      },
      ...
    ]
  },
  "locations": {
    "doc_count_error_upper_bound": 0,
    "sum_other_doc_count": 0,
    "buckets": [
      {
        "key": "San Francisco, CA",
        "doc_count": 4
      },
      {
        "key": "New York, NY",
        "doc_count": 3
      },
      ...
    ]
  },
  "funding_stages": {
    "doc_count_error_upper_bound": 0,
    "sum_other_doc_count": 0,
    "buckets": [
      {
        "key": "Series A",
        "doc_count": 8
      },
      ...
    ]
  },
  "business_models": {
    "doc_count_error_upper_bound": 0,
    "sum_other_doc_count": 0,
    "buckets": [
      {
        "key": "B2B",
        "doc_count": 13
      },
      ...
    ]
  },
  "lead_investors": {
    "doc_count_error_upper_bound": 0,
    "sum_other_doc_count": 0,
    "buckets": [
      {
        "key": "Battery Ventures",
        "doc_count": 1
      },
      {
        "key": "Benchmark Capital",
        "doc_count": 1
      },
      ...
    ]
  },
  "funding_amount_stats": {
    "count": 20,
    "min": 4500000,
    "max": 35000000,
    "avg": 14075000,
    "sum": 281500000
  }
}

await esClient.putScript({
      id: INVESTMENT_FOCUSED_TEMPLATE,
      script: {
        lang: "mustache",
        source: `{
          "size": 5,
          "retriever": {
            "rrf": {
              "retrievers": [
                {
                  "standard": {
                    "query": {
                      "semantic": {
                        "field": "semantic_field",
                        "query": "{{query_text}}"
                      }
                    }
                  }
                },
                {
                  "standard": {
                    "query": {
                      "bool": {
                        "filter": [
                          {"terms": {"funding_stage": {{#join}}{{#toJson}}funding_stage{{/toJson}}{{/join}}}},
                          {"range": {"funding_amount": {"gte": {{funding_amount_gte}}{{#funding_amount_lte}},"lte": {{funding_amount_lte}}{{/funding_amount_lte}}}}},
                          {"terms": {"lead_investor": {{#join}}{{#toJson}}lead_investor{{/toJson}}{{/join}}}},
                          {"range": {"monthly_revenue": {"gte": {{monthly_revenue_gte}}{{#monthly_revenue_lte}},"lte": {{monthly_revenue_lte}}{{/monthly_revenue_lte}}}}}
                        ]
                      }
                    }
                  }
                }
              ],
              "rank_window_size": 100,
              "rank_constant": 20
            }
          }
        }`,
      },
    });

// Node 1: Decide search strategy using LLM
async function decideSearchStrategy(state: typeof VCState.State) {
  // Zod schema for specialized search strategy decision
  const SearchDecisionSchema = z.object({
    search_type: z
      .enum(["investment_focused", "market_focused"])
      .describe("Type of specialized search strategy to use"),
    reasoning: z
      .string()
      .describe("Brief explanation of why this search strategy was chosen"),
  });

  const decisionLLM = llm.withStructuredOutput(SearchDecisionSchema);

  // Get dynamic filters from Elasticsearch
  const availableFilters = await getAvailableFilters();

  const prompt = `Query: "${state.input}"
    Available filters: ${JSON.stringify(availableFilters, null, 2)}

    Choose between two specialized search strategies:
    
    - investment_focused: For queries about funding stages, funding amounts, monthly revenue, lead investors, financial performance
    
    - market_focused: For queries about industries, locations, business models, market segments, geographic markets
    
    Analyze the query intent and choose the most appropriate strategy.
  `;

  try {
    const result = await decisionLLM.invoke(prompt);
    console.log(
      `🤔 Search strategy: ${result.search_type} - ${result.reasoning}`
    );

    return {
      searchStrategy: result.search_type,
    };
  } catch (error: any) {
    console.error("❌ Error in decideSearchStrategy:", error.message);
    return {
      searchStrategy: "investment_focused",
    };
  }
}

// Extract all possible filter values from user input
async function extractFilterValues(input: string) {
  const FilterValuesSchema = z.object({
    // Investment-focused filters
    funding_stage: z
      .array(z.string())
      .default([])
      .describe("Funding stage values mentioned in query"),
    funding_amount_gte: z
      .number()
      .default(0)
      .describe("Minimum funding amount in USD"),
    funding_amount_lte: z
      .number()
      .default(100000000)
      .describe("Maximum funding amount in USD"),
    lead_investor: z
      .array(z.string())
      .default([])
      .describe("Lead investor values mentioned in query"),
    monthly_revenue_gte: z
      .number()
      .default(0)
      .describe("Minimum monthly revenue in USD"),
    monthly_revenue_lte: z
      .number()
      .default(10000000)
      .describe("Maximum monthly revenue in USD"),
    industry: z
      .array(z.string())
      .default([])
      .describe("Industry values mentioned in query"),
    location: z
      .array(z.string())
      .default([])
      .describe("Location values mentioned in query"),
    business_model: z
      .array(z.string())
      .default([])
      .describe("Business model values mentioned in query"),
  });

  const extractorLLM = llm.withStructuredOutput(FilterValuesSchema);
  const availableFilters = await getAvailableFilters();

  const extractPrompt = `Extract ALL relevant filter values from: "${input}"
    Available options: ${JSON.stringify(availableFilters, null, 2)}
    Extract only values explicitly mentioned in the query. Leave fields empty if not mentioned.`;

  return await extractorLLM.invoke(extractPrompt);
}

// Node 2A: Prepare Investment-Focused Search Parameters 
async function prepareInvestmentSearch(state: typeof VCState.State) {
  console.log(
    "💰 Preparing INVESTMENT-FOCUSED search parameters with financial emphasis..."
  );

  try {
    // Extract all filter values from input
    const values = await extractFilterValues(state.input);

    let searchParams: any = {
      template_id: INVESTMENT_FOCUSED_TEMPLATE,
      query_text: state.input,
      ...values,
    };

    return { searchParams };
  } catch (error) {
    console.error("❌ Error preparing investment-focused params:", error);
    return {
      searchParams: {},
    };
  }
}

// Node 2B: Prepare Market-Focused Search Parameters
async function prepareMarketSearch(state: typeof VCState.State) {
  console.log(
    "🔍 Preparing MARKET-FOCUSED search parameters with market emphasis..."
  );

  try {
    // Extract all filter values from input
    const values = await extractFilterValues(state.input);

    let searchParams: any = {
      template_id: MARKET_FOCUSED_TEMPLATE,
      query_text: state.input,
      ...values,
    };

    return { searchParams };
  } catch (error) {
    console.error("❌ Error preparing market-focused params:", error);
    return {};
  }
}

// Node 3: Execute Search
async function executeSearch(state: typeof VCState.State) {
  const { searchParams } = state;

  try {
    // getting formed query from template for debugging
    const renderedTemplate = await esClient.renderSearchTemplate({
      id: searchParams.template_id,
      params: searchParams,
    });

    console.log(
      "📋 Complete query:",
      JSON.stringify(renderedTemplate.template_output, null, 2)
    );

    const results = await esClient.searchTemplate({
      index: INDEX_NAME,
      id: searchParams.template_id,
      params: searchParams,
    });

    return {
      results: results.hits.hits.map((hit: any) => hit._source),
    };
  } catch (error: any) {
    console.error(`❌ ${state.searchParams.search_type} search error:`, error);
    return { results: [] };
  }
}

// Node 4: Visualize results
async function visualizeResults(state: typeof VCState.State) {
  const results = state.results || [];

  let formattedResults = `🎯 Found ${results.length} startups matching your criteria:\n\n`;

  results.forEach((startup: any, index: number) => {
    formattedResults += `${index + 1}. **${startup.company_name}**\n`;
    formattedResults += `   📍 ${startup.location} | 🏢 ${startup.industry} | 💼 ${startup.business_model}\n`;
    formattedResults += `   💰 ${startup.funding_stage} - $${(
      startup.funding_amount / 1000000
    ).toFixed(1)}M\n`;
    formattedResults += `   👥 ${startup.employee_count} employees | 📈 $${(
      startup.monthly_revenue / 1000
    ).toFixed(0)}K MRR\n`;
    formattedResults += `   🏦 Lead: ${startup.lead_investor}\n`;
    formattedResults += `   📝 ${startup.description}\n\n`;
  });

  return {
    final: formattedResults,
  };
}

  const workflow = new StateGraph(VCState)
    // Register nodes - these are the processing functions
    .addNode("decideStrategy", decideSearchStrategy)
    .addNode("prepareInvestment", prepareInvestmentSearch)
    .addNode("prepareMarket", prepareMarketSearch)
    .addNode("executeSearch", executeSearch)
    .addNode("visualizeResults", visualizeResults)
    // Define execution flow with conditional branching
    .addEdge(START, "decideStrategy") // Start with strategy decision
    .addConditionalEdges(
      "decideStrategy",
      (state: typeof VCState.State) => state.searchStrategy, // Conditional function
      {
        investment_focused: "prepareInvestment", // If investment focused -> RRF template preparation
        market_focused: "prepareMarket", // If market focused -> dynamic query preparation
      }
    )
    .addEdge("prepareInvestment", "executeSearch") // Investment prep -> execute
    .addEdge("prepareMarket", "executeSearch") // Market prep -> execute
    .addEdge("executeSearch", "visualizeResults") // Execute -> visualize
    .addEdge("visualizeResults", END); // End workflow

async function main() {
  await createIndex();
  await createSearchTemplates();
  await ingestDocuments();

  // Create the workflow graph with shared state
  const workflow = new StateGraph(VCState)
    // Register nodes - these are the processing functions
    .addNode("decideStrategy", decideSearchStrategy)
    .addNode("prepareInvestment", prepareInvestmentSearch)
    .addNode("prepareMarket", prepareMarketSearch)
    .addNode("executeSearch", executeSearch)
    .addNode("visualizeResults", visualizeResults)
    // Define execution flow with conditional branching
    .addEdge(START, "decideStrategy") // Start with strategy decision
    .addConditionalEdges(
      "decideStrategy",
      (state: typeof VCState.State) => state.searchStrategy, // Conditional function
      {
        investment_focused: "prepareInvestment", // If investment focused -> RRF template preparation
        market_focused: "prepareMarket", // If market focused -> dynamic query preparation
      }
    )
    .addEdge("prepareInvestment", "executeSearch") // Investment prep -> execute
    .addEdge("prepareMarket", "executeSearch") // Market prep -> execute
    .addEdge("executeSearch", "visualizeResults") // Execute -> visualize
    .addEdge("visualizeResults", END); // End workflow


  const app = workflow.compile();

  await saveGraphImage(app);

  const query =
    "Find startups with Series A or Series B funding between $8M-$25M and monthly revenue above $500K";

  const marketResult = await app.invoke({ input: query });
  console.log(marketResult.final);
}

main().catch(console.error);

🔍 Checking if index exists...
🏗️ Creating index...
✅ Index created successfully!
Ingesting documents...
✅ Documents ingested successfully!
✅ Investment-focused template created successfully!
✅ Market-focused template created successfully!

📊 Workflow graph saved as: ./workflow_graph.png

🔍 Query: "Find startups with Series A or Series B funding between $8M-$25M and monthly revenue above $500K"

🤔 Search strategy: investment_focused - The query specifically seeks profitable fintech startups with defined funding amounts and high monthly revenue, which aligns closely with financial performance metrics and investment-related criteria.

💰 Preparing INVESTMENT-FOCUSED search parameters with financial emphasis...

📋 Complete query: {
  "size": 5,
  "retriever": {
    "rrf": {
      "retrievers": [
        {
          "standard": {
            "query": {
              "semantic": {
                "field": "semantic_field",
                "query": "Find startups with Series A or Series B funding between $8M-$25M and monthly revenue above $500K"
              }
            }
          }
        },
        {
          "standard": {
            "query": {
              "bool": {
                "filter": [
                  {
                    "terms": {
                      "funding_stage": [
                        "Series A",
                        "Series B"
                      ]
                    }
                  },
                  {
                    "range": {
                      "funding_amount": {
                        "gte": 8000000,
                        "lte": 25000000
                      }
                    }
                  },
                  {
                    "terms": {
                      "lead_investor": []
                    }
                  },
                  {
                    "range": {
                      "monthly_revenue": {
                        "gte": 500000,
                        "lte": 0
                      }
                    }
                  }
                ]
              }
            }
          }
        }
      ],
      "rank_window_size": 100,
      "rank_constant": 20
    }
  }
}
🎯 Found 5 startups matching your criteria:

1. **TechFlow**
   📍 San Francisco, CA | 🏢 logistics | 💼 B2B
   💰 Series A - $8.0M
   👥 45 employees | 📈 $500K MRR
   🏦 Lead: Sequoia Capital
   📝 TechFlow optimizes supply chain operations using AI-powered route optimization and real-time tracking. Founded in 2023, shows remarkable growth with $500K monthly revenue.

2. **DataViz**
   📍 New York, NY | 🏢 enterprise software | 💼 B2B
   💰 Series A - $10.0M
   👥 42 employees | 📈 $450K MRR
   🏦 Lead: Battery Ventures
   📝 DataViz creates intuitive data visualization tools for enterprise customers. No-code platform allows business users to create dashboards without technical expertise.

3. **FinanceAI**
   📍 San Francisco, CA | 🏢 fintech | 💼 B2C
   💰 Series C - $25.0M
   👥 120 employees | 📈 $1200K MRR
   🏦 Lead: Tiger Global Management
   📝 FinanceAI provides AI-powered investment advisory services to retail investors. Uses machine learning to analyze market trends with over 100,000 active users.

4. **UrbanMobility**
   📍 New York, NY | 🏢 logistics | 💼 B2B2C
   💰 Series B - $15.0M
   👥 78 employees | 📈 $750K MRR
   🏦 Lead: Kleiner Perkins
   📝 UrbanMobility revolutionizes urban transportation through autonomous delivery drones and smart logistics hubs. Partners with major retailers for same-day delivery across Manhattan and Brooklyn.

5. **HealthTech Solutions**
   📍 Boston, MA | 🏢 healthcare | 💼 B2B
   💰 Series B - $18.0M
   👥 95 employees | 📈 $900K MRR
   🏦 Lead: General Catalyst
   📝 HealthTech Solutions develops medical devices and software for remote patient monitoring. Comprehensive telehealth platform reducing hospital readmissions by 30%.

✨  Done in 18.80s.

...

🔍 Query: Find fintech and healthcare startups in San Francisco, New York, or Boston

🤔 Search strategy: market_focused - The query is focused on finding fintech startups in San Francisco that are disrupting traditional banking and payment systems, which pertains to specific industries (fintech) and locations (San Francisco). Thus, a market-focused strategy is more appropriate.

🔍 Preparing MARKET-FOCUSED search parameters with market emphasis...

📋 Complete query: {
  "size": 5,
  "retriever": {
    "rrf": {
      "retrievers": [
        {
          "standard": {
            "query": {
              "semantic": {
                "field": "semantic_field",
                "query": "Find fintech and healthcare startups in San Francisco, New York, or Boston"
              }
            }
          }
        },
        {
          "standard": {
            "query": {
              "bool": {
                "filter": [
                  {
                    "terms": {
                      "industry": [
                        "fintech",
                        "healthcare"
                      ]
                    }
                  },
                  {
                    "terms": {
                      "location": [
                        "San Francisco, CA",
                        "New York, NY",
                        "Boston, MA"
                      ]
                    }
                  },
                  {
                    "terms": {
                      "business_model": []
                    }
                  }
                ]
              }
            }
          }
        }
      ],
      "rank_window_size": 50,
      "rank_constant": 10
    }
  }
}
🎯 Found 5 startups matching your criteria:

1. **FinanceAI**
   📍 San Francisco, CA | 🏢 fintech | 💼 B2C
   💰 Series C - $25.0M
   👥 120 employees | 📈 $1200K MRR
   🏦 Lead: Tiger Global Management
   📝 FinanceAI provides AI-powered investment advisory services to retail investors. Uses machine learning to analyze market trends with over 100,000 active users.

2. **CryptoWallet**
   📍 Miami, FL | 🏢 fintech | 💼 B2C
   💰 Series B - $16.0M
   👥 73 employees | 📈 $820K MRR
   🏦 Lead: Coinbase Ventures
   📝 CryptoWallet provides secure digital wallet solutions for cryptocurrency trading and storage. Multi-chain support with enterprise-grade security features.

...

✨  Done in 7.41s.