Integration Patterns for Agentic Systems: Playing Nice with Legacy Infrastructure

How Fortune 500 companies seamlessly integrate autonomous agents with decades-old systems, creating hybrid architectures that unlock $47M in operational value while preserving $2.3B in existing infrastructure investments

The enterprise integration challenge for agentic systems isn’t just technical—it’s existential. Organizations face a $847 billion legacy infrastructure investment that can’t be abandoned, yet competitive pressure demands autonomous capabilities that traditional systems can’t provide. The solution isn’t replacement—it’s intelligent integration.

Analysis of 3,247 enterprise integration projects reveals that organizations using proven agentic integration patterns achieve 73% lower integration costs, 340% faster deployment timelines, and 267% higher ROI compared to those attempting wholesale replacement. These patterns don’t just preserve legacy investments—they amplify them through autonomous enhancement.

The $847B Legacy Integration Opportunity

Modern enterprises operate an average of 347 different software systems, with 67% predating the cloud era and 23% predating the internet. These systems collectively represent $847 billion in global enterprise investment, contain decades of business logic, and process 89% of critical business operations.

The traditional approach—wholesale replacement—has a 78% failure rate and averages $23M per major system replacement. The agentic approach—intelligent integration—has an 89% success rate and averages $2.1M per system enhancement while delivering comparable business value.

Consider two Fortune 100 retailers modernizing their inventory management:

Company A (Replacement Strategy): $47M investment to replace 30-year-old mainframe inventory system. Result: 34-month project timeline, 67% functionality loss during transition, $8.9M annual maintenance increase, 23% customer service degradation during migration.

Company B (Integration Strategy): $3.2M investment to integrate agentic layer with existing mainframe. Result: 6-month project timeline, zero functionality loss, 89% improvement in predictive capabilities, 156% improvement in inventory optimization, $4.7M annual cost savings through enhanced automation.

The difference: Company B preserved their battle-tested business logic while enhancing it with autonomous intelligence. Company A lost decades of accumulated business intelligence while building new systems from scratch.

Core Integration Architecture Patterns

The Agentic Proxy Pattern

interface AgenticProxy {
  legacySystem: LegacySystemAdapter;
  agentLayer: AgentOrchestrator;
  translationEngine: DataTranslationEngine;
  monitoringSystem: IntegrationMonitoring;
}

class AgenticProxyOrchestrator {
  private legacyAdapters: Map<string, LegacySystemAdapter>;
  private agentNetwork: AgentNetwork;
  private translationEngine: DataTranslationEngine;
  private monitoringSystem: IntegrationMonitoring;

  constructor(config: IntegrationConfig) {
    this.legacyAdapters = this.initializeLegacyAdapters(config.legacySystems);
    this.agentNetwork = new AgentNetwork(config.agents);
    this.translationEngine = new DataTranslationEngine(config.translations);
    this.monitoringSystem = new IntegrationMonitoring(config.monitoring);
  }

  async processBusinessRequest(
    request: BusinessRequest,
    context: BusinessContext
  ): Promise<BusinessResponse> {
    const executionPlan = await this.planExecution(request, context);
    const optimizedPlan = await this.optimizeExecutionPlan(executionPlan);
    
    const results = await this.executeHybridWorkflow(optimizedPlan);
    const consolidatedResponse = await this.consolidateResults(results);
    
    await this.monitoringSystem.recordExecution({
      request,
      executionPlan: optimizedPlan,
      results,
      response: consolidatedResponse,
      performance: await this.calculatePerformanceMetrics(results)
    });

    return consolidatedResponse;
  }

  private async planExecution(
    request: BusinessRequest,
    context: BusinessContext
  ): Promise<ExecutionPlan> {
    const capabilities = await this.assessCapabilities(request);
    const systemRequirements = await this.analyzeSystemRequirements(request);
    
    const agentCapabilities = await this.agentNetwork.assessCapabilities(
      request,
      context
    );
    const legacyCapabilities = await this.assessLegacyCapabilities(
      request,
      systemRequirements
    );

    return {
      agentTasks: this.identifyAgentTasks(request, agentCapabilities),
      legacyTasks: this.identifyLegacyTasks(request, legacyCapabilities),
      coordinationPoints: this.identifyCoordinationPoints(
        agentCapabilities,
        legacyCapabilities
      ),
      dataFlows: await this.planDataFlows(request, capabilities),
      fallbackStrategies: await this.planFallbackStrategies(request)
    };
  }

  private async executeHybridWorkflow(
    plan: ExecutionPlan
  ): Promise<ExecutionResults> {
    const parallelExecutions = await this.identifyParallelExecutions(plan);
    const sequentialDependencies = await this.identifySequentialDependencies(
      plan
    );

    const results = new Map<string, TaskResult>();
    
    // Execute parallel tasks
    for (const parallelGroup of parallelExecutions) {
      const groupResults = await Promise.all(
        parallelGroup.map(task => this.executeTask(task, results))
      );
      
      groupResults.forEach((result, index) => {
        results.set(parallelGroup[index].id, result);
      });
    }

    // Execute sequential dependencies
    for (const dependencyChain of sequentialDependencies) {
      for (const task of dependencyChain) {
        const result = await this.executeTask(task, results);
        results.set(task.id, result);
      }
    }

    return {
      taskResults: results,
      executionMetrics: await this.calculateExecutionMetrics(results),
      integrationHealth: await this.assessIntegrationHealth(results),
      businessValue: await this.calculateBusinessValue(results)
    };
  }

  private async executeTask(
    task: ExecutionTask,
    previousResults: Map<string, TaskResult>
  ): Promise<TaskResult> {
    const startTime = Date.now();
    
    try {
      let result: TaskResult;
      
      if (task.type === TaskType.AGENT_TASK) {
        result = await this.executeAgentTask(task, previousResults);
      } else if (task.type === TaskType.LEGACY_TASK) {
        result = await this.executeLegacyTask(task, previousResults);
      } else if (task.type === TaskType.COORDINATION_TASK) {
        result = await this.executeCoordinationTask(task, previousResults);
      } else {
        throw new Error(`Unknown task type: ${task.type}`);
      }

      await this.monitoringSystem.recordTaskExecution({
        task,
        result,
        executionTime: Date.now() - startTime,
        status: 'success'
      });

      return result;
    } catch (error) {
      await this.monitoringSystem.recordTaskExecution({
        task,
        error,
        executionTime: Date.now() - startTime,
        status: 'error'
      });

      const fallbackResult = await this.executeFallbackStrategy(task, error);
      return fallbackResult;
    }
  }
}

Legacy System Adaptation Layer

interface LegacySystemAdapter {
  systemId: string;
  systemType: LegacySystemType;
  capabilities: SystemCapability[];
  dataFormat: DataFormatSpecification;
  communicationProtocol: CommunicationProtocol;
  
  connect(): Promise<ConnectionResult>;
  executeOperation(operation: LegacyOperation): Promise<OperationResult>;
  translateData(data: any, targetFormat: DataFormat): Promise<any>;
  monitorHealth(): Promise<HealthStatus>;
}

class MainframeLegacyAdapter implements LegacySystemAdapter {
  systemId = "mainframe-core";
  systemType = LegacySystemType.MAINFRAME;
  
  private connectionPool: ConnectionPool;
  private transactionManager: TransactionManager;
  private dataTranslator: MainframeDataTranslator;

  constructor(config: MainframeConfig) {
    this.connectionPool = new ConnectionPool(config.connection);
    this.transactionManager = new TransactionManager(config.transactions);
    this.dataTranslator = new MainframeDataTranslator(config.dataFormats);
  }

  async executeOperation(
    operation: LegacyOperation
  ): Promise<OperationResult> {
    const connection = await this.connectionPool.acquire();
    const transaction = await this.transactionManager.begin(connection);
    
    try {
      const translatedInput = await this.dataTranslator.toMainframeFormat(
        operation.input
      );
      
      const mainframeResult = await this.executeMainframeTransaction(
        translatedInput,
        operation.procedure,
        transaction
      );
      
      const translatedOutput = await this.dataTranslator.fromMainframeFormat(
        mainframeResult
      );
      
      await this.transactionManager.commit(transaction);
      
      return {
        success: true,
        data: translatedOutput,
        metadata: {
          executionTime: mainframeResult.executionTime,
          resourceUsage: mainframeResult.resourceUsage,
          transactionId: transaction.id
        }
      };
    } catch (error) {
      await this.transactionManager.rollback(transaction);
      throw new LegacySystemError(
        `Mainframe operation failed: ${error.message}`,
        operation,
        error
      );
    } finally {
      await this.connectionPool.release(connection);
    }
  }

  private async executeMainframeTransaction(
    input: MainframeData,
    procedure: string,
    transaction: Transaction
  ): Promise<MainframeResult> {
    const cobolProgram = await this.loadCobolProgram(procedure);
    const executionContext = await this.createExecutionContext(
      input,
      transaction
    );
    
    const result = await cobolProgram.execute(executionContext);
    
    return {
      data: result.output,
      executionTime: result.executionTime,
      resourceUsage: result.resourceUsage,
      logs: result.logs
    };
  }

  async monitorHealth(): Promise<HealthStatus> {
    const connectionHealth = await this.connectionPool.checkHealth();
    const systemLoad = await this.checkSystemLoad();
    const transactionBacklog = await this.transactionManager.getBacklogSize();
    
    return {
      status: this.determineOverallHealth([
        connectionHealth,
        systemLoad,
        transactionBacklog
      ]),
      metrics: {
        connectionPoolUtilization: connectionHealth.utilization,
        averageResponseTime: systemLoad.averageResponseTime,
        transactionThroughput: systemLoad.transactionThroughput,
        errorRate: systemLoad.errorRate,
        backlogSize: transactionBacklog
      },
      alerts: this.generateHealthAlerts([
        connectionHealth,
        systemLoad,
        transactionBacklog
      ])
    };
  }
}

class RestApiLegacyAdapter implements LegacySystemAdapter {
  systemId: string;
  systemType = LegacySystemType.REST_API;
  
  private httpClient: HttpClient;
  private rateLimiter: RateLimiter;
  private cacheLayer: CacheLayer;
  private circuitBreaker: CircuitBreaker;

  constructor(config: RestApiConfig) {
    this.systemId = config.systemId;
    this.httpClient = new HttpClient(config.http);
    this.rateLimiter = new RateLimiter(config.rateLimit);
    this.cacheLayer = new CacheLayer(config.cache);
    this.circuitBreaker = new CircuitBreaker(config.circuitBreaker);
  }

  async executeOperation(
    operation: LegacyOperation
  ): Promise<OperationResult> {
    await this.rateLimiter.waitForToken();
    
    const cacheKey = this.generateCacheKey(operation);
    const cachedResult = await this.cacheLayer.get(cacheKey);
    
    if (cachedResult && this.isCacheValid(cachedResult, operation)) {
      return cachedResult;
    }

    return await this.circuitBreaker.execute(async () => {
      const request = this.buildHttpRequest(operation);
      const response = await this.httpClient.execute(request);
      
      const result = {
        success: response.status < 400,
        data: response.data,
        metadata: {
          statusCode: response.status,
          headers: response.headers,
          executionTime: response.executionTime
        }
      };

      if (result.success && this.isCacheable(operation)) {
        await this.cacheLayer.set(cacheKey, result, operation.cacheTtl);
      }

      return result;
    });
  }

  private buildHttpRequest(operation: LegacyOperation): HttpRequest {
    return {
      method: operation.method || 'POST',
      url: this.buildUrl(operation.endpoint, operation.parameters),
      headers: {
        ...this.getAuthHeaders(),
        ...operation.headers,
        'Content-Type': 'application/json'
      },
      body: operation.input ? JSON.stringify(operation.input) : undefined,
      timeout: operation.timeout || 30000
    };
  }

  async monitorHealth(): Promise<HealthStatus> {
    const circuitBreakerStatus = this.circuitBreaker.getStatus();
    const rateLimiterStatus = this.rateLimiter.getStatus();
    const cacheStatus = await this.cacheLayer.getStatus();
    
    const healthCheck = await this.performHealthCheck();
    
    return {
      status: this.determineOverallHealth([
        circuitBreakerStatus,
        rateLimiterStatus,
        cacheStatus,
        healthCheck
      ]),
      metrics: {
        circuitBreakerState: circuitBreakerStatus.state,
        rateLimitUtilization: rateLimiterStatus.utilization,
        cacheHitRate: cacheStatus.hitRate,
        averageResponseTime: healthCheck.averageResponseTime,
        errorRate: healthCheck.errorRate
      },
      alerts: this.generateHealthAlerts([
        circuitBreakerStatus,
        rateLimiterStatus,
        cacheStatus,
        healthCheck
      ])
    };
  }
}

Data Translation and Transformation Engine

class DataTranslationEngine {
  private translators: Map<string, DataTranslator>;
  private schemaRegistry: SchemaRegistry;
  private transformationCache: TransformationCache;
  private validationEngine: DataValidationEngine;

  constructor(config: TranslationEngineConfig) {
    this.translators = this.initializeTranslators(config.translators);
    this.schemaRegistry = new SchemaRegistry(config.schemas);
    this.transformationCache = new TransformationCache(config.cache);
    this.validationEngine = new DataValidationEngine(config.validation);
  }

  async translateData(
    data: any,
    sourceFormat: DataFormat,
    targetFormat: DataFormat,
    context: TranslationContext
  ): Promise<TranslationResult> {
    const cacheKey = this.generateTranslationCacheKey(
      data,
      sourceFormat,
      targetFormat
    );
    
    const cachedTranslation = await this.transformationCache.get(cacheKey);
    if (cachedTranslation && this.isCacheValid(cachedTranslation, context)) {
      return cachedTranslation;
    }

    const sourceSchema = await this.schemaRegistry.getSchema(sourceFormat.id);
    const targetSchema = await this.schemaRegistry.getSchema(targetFormat.id);
    
    const validationResult = await this.validationEngine.validate(
      data,
      sourceSchema
    );
    
    if (!validationResult.isValid) {
      throw new DataValidationError(
        `Source data validation failed: ${validationResult.errors.join(', ')}`,
        data,
        sourceSchema,
        validationResult.errors
      );
    }

    const translator = this.getTranslator(sourceFormat, targetFormat);
    const transformationResult = await translator.transform(
      data,
      sourceSchema,
      targetSchema,
      context
    );

    const targetValidationResult = await this.validationEngine.validate(
      transformationResult.data,
      targetSchema
    );

    if (!targetValidationResult.isValid) {
      throw new DataTransformationError(
        `Target data validation failed: ${targetValidationResult.errors.join(', ')}`,
        transformationResult.data,
        targetSchema,
        targetValidationResult.errors
      );
    }

    const finalResult = {
      data: transformationResult.data,
      metadata: {
        sourceFormat,
        targetFormat,
        transformationPath: transformationResult.transformationPath,
        dataQuality: this.assessDataQuality(
          data,
          transformationResult.data,
          context
        ),
        performance: transformationResult.performance
      }
    };

    await this.transformationCache.set(cacheKey, finalResult);
    
    return finalResult;
  }

  private getTranslator(
    sourceFormat: DataFormat,
    targetFormat: DataFormat
  ): DataTranslator {
    const directTranslatorKey = `${sourceFormat.id}->${targetFormat.id}`;
    const directTranslator = this.translators.get(directTranslatorKey);
    
    if (directTranslator) {
      return directTranslator;
    }

    // Find transformation path through intermediate formats
    const transformationPath = this.findTransformationPath(
      sourceFormat,
      targetFormat
    );
    
    if (!transformationPath) {
      throw new TranslationError(
        `No transformation path found from ${sourceFormat.id} to ${targetFormat.id}`
      );
    }

    return new ChainedDataTranslator(transformationPath, this.translators);
  }

  private findTransformationPath(
    sourceFormat: DataFormat,
    targetFormat: DataFormat
  ): TransformationPath | null {
    const visited = new Set<string>();
    const queue = [{ format: sourceFormat, path: [sourceFormat] }];
    
    while (queue.length > 0) {
      const current = queue.shift()!;
      
      if (current.format.id === targetFormat.id) {
        return new TransformationPath(current.path);
      }
      
      if (visited.has(current.format.id)) {
        continue;
      }
      
      visited.add(current.format.id);
      
      const availableTranslations = this.getAvailableTranslations(
        current.format
      );
      
      for (const translation of availableTranslations) {
        if (!visited.has(translation.target.id)) {
          queue.push({
            format: translation.target,
            path: [...current.path, translation.target]
          });
        }
      }
    }
    
    return null;
  }
}

class AgentLegacyDataTranslator implements DataTranslator {
  async transform(
    data: any,
    sourceSchema: DataSchema,
    targetSchema: DataSchema,
    context: TranslationContext
  ): Promise<TransformationResult> {
    const mappingStrategy = await this.determineMappingStrategy(
      sourceSchema,
      targetSchema,
      context
    );

    const transformationSteps = await this.generateTransformationSteps(
      mappingStrategy
    );

    let currentData = data;
    const appliedTransformations = [];

    for (const step of transformationSteps) {
      const stepResult = await this.applyTransformationStep(
        currentData,
        step,
        context
      );
      
      currentData = stepResult.data;
      appliedTransformations.push(stepResult.transformation);
    }

    const dataQualityAssessment = await this.assessDataQuality(
      data,
      currentData,
      sourceSchema,
      targetSchema
    );

    return {
      data: currentData,
      transformationPath: appliedTransformations,
      dataQuality: dataQualityAssessment,
      performance: {
        transformationTime: Date.now() - context.startTime,
        memoryUsage: process.memoryUsage(),
        stepCount: transformationSteps.length
      }
    };
  }

  private async determineMappingStrategy(
    sourceSchema: DataSchema,
    targetSchema: DataSchema,
    context: TranslationContext
  ): Promise<MappingStrategy> {
    const structuralAnalysis = this.analyzeStructuralDifferences(
      sourceSchema,
      targetSchema
    );
    
    const semanticAnalysis = await this.analyzeSemanticRelationships(
      sourceSchema,
      targetSchema,
      context
    );

    const complexityAnalysis = this.analyzeTransformationComplexity(
      structuralAnalysis,
      semanticAnalysis
    );

    return {
      approach: this.selectMappingApproach(complexityAnalysis),
      fieldMappings: this.generateFieldMappings(
        sourceSchema,
        targetSchema,
        semanticAnalysis
      ),
      valueTransformations: this.generateValueTransformations(
        structuralAnalysis,
        semanticAnalysis
      ),
      dataValidations: this.generateDataValidations(targetSchema),
      fallbackStrategies: this.generateFallbackStrategies(complexityAnalysis)
    };
  }
}

Gradual Migration Patterns

The Strangler Fig Pattern for Legacy Replacement

class StranglerFigMigrationOrchestrator {
  private migrationState: MigrationState;
  private trafficRouter: TrafficRouter;
  private dataSync: DataSynchronizer;
  private rollbackManager: RollbackManager;

  constructor(config: MigrationConfig) {
    this.migrationState = new MigrationState(config.initialState);
    this.trafficRouter = new TrafficRouter(config.routing);
    this.dataSync = new DataSynchronizer(config.dataSync);
    this.rollbackManager = new RollbackManager(config.rollback);
  }

  async planMigration(
    legacySystem: LegacySystem,
    targetSystem: AgenticSystem
  ): Promise<MigrationPlan> {
    const systemAnalysis = await this.analyzeLegacySystem(legacySystem);
    const capabilityMapping = await this.mapCapabilities(
      legacySystem,
      targetSystem
    );
    
    const migrationPhases = await this.generateMigrationPhases(
      systemAnalysis,
      capabilityMapping
    );

    const riskAssessment = await this.assessMigrationRisks(migrationPhases);
    const rollbackStrategies = await this.planRollbackStrategies(
      migrationPhases
    );

    return {
      phases: migrationPhases,
      riskAssessment,
      rollbackStrategies,
      timeline: this.calculateMigrationTimeline(migrationPhases),
      costs: await this.estimateMigrationCosts(migrationPhases),
      benefits: await this.estimateMigrationBenefits(migrationPhases)
    };
  }

  async executeMigrationPhase(
    phase: MigrationPhase,
    options: MigrationExecutionOptions
  ): Promise<MigrationPhaseResult> {
    const preExecutionCheck = await this.performPreExecutionChecks(phase);
    if (!preExecutionCheck.passed) {
      throw new MigrationError(
        `Pre-execution checks failed: ${preExecutionCheck.failures.join(', ')}`
      );
    }

    const checkpoint = await this.createMigrationCheckpoint(phase);
    
    try {
      const deploymentResult = await this.deployAgenticCapabilities(
        phase.targetCapabilities
      );
      
      const dataSyncResult = await this.synchronizeData(
        phase.dataMigration,
        options.dataSyncMode
      );
      
      const trafficMigrationResult = await this.migrateTraffic(
        phase.trafficMigration,
        options.trafficMigrationStrategy
      );
      
      const validationResult = await this.validateMigrationPhase(phase);
      
      if (validationResult.passed) {
        await this.commitMigrationPhase(phase);
        await this.updateMigrationState(phase);
        
        return {
          success: true,
          phase,
          deploymentResult,
          dataSyncResult,
          trafficMigrationResult,
          validationResult,
          performance: await this.measureMigrationPerformance(phase)
        };
      } else {
        await this.rollbackManager.rollbackPhase(phase, checkpoint);
        throw new MigrationValidationError(
          `Migration phase validation failed: ${validationResult.failures.join(', ')}`
        );
      }
    } catch (error) {
      await this.rollbackManager.rollbackPhase(phase, checkpoint);
      throw error;
    }
  }

  private async migrateTraffic(
    trafficMigration: TrafficMigration,
    strategy: TrafficMigrationStrategy
  ): Promise<TrafficMigrationResult> {
    const baselineMetrics = await this.captureBaselineMetrics();
    
    switch (strategy.type) {
      case TrafficMigrationStrategy.CANARY:
        return await this.executeCanaryMigration(
          trafficMigration,
          strategy,
          baselineMetrics
        );
      
      case TrafficMigrationStrategy.BLUE_GREEN:
        return await this.executeBlueGreenMigration(
          trafficMigration,
          strategy,
          baselineMetrics
        );
      
      case TrafficMigrationStrategy.FEATURE_FLAG:
        return await this.executeFeatureFlagMigration(
          trafficMigration,
          strategy,
          baselineMetrics
        );
      
      default:
        throw new Error(`Unsupported traffic migration strategy: ${strategy.type}`);
    }
  }

  private async executeCanaryMigration(
    trafficMigration: TrafficMigration,
    strategy: CanaryMigrationStrategy,
    baselineMetrics: MetricsSnapshot
  ): Promise<TrafficMigrationResult> {
    const canarySteps = strategy.steps.sort((a, b) => a.trafficPercentage - b.trafficPercentage);
    const migrationResults = [];

    for (const step of canarySteps) {
      const stepStartTime = Date.now();
      
      await this.trafficRouter.updateRouting({
        legacyPercentage: 100 - step.trafficPercentage,
        agenticPercentage: step.trafficPercentage,
        routingCriteria: step.routingCriteria
      });

      await this.waitForStabilization(strategy.stabilizationTime);
      
      const stepMetrics = await this.captureStepMetrics(step);
      const healthCheck = await this.performHealthCheck();
      
      const stepResult = {
        step,
        metrics: stepMetrics,
        healthCheck,
        duration: Date.now() - stepStartTime
      };

      migrationResults.push(stepResult);

      if (!this.isStepSuccessful(stepResult, baselineMetrics, strategy.successCriteria)) {
        await this.trafficRouter.rollbackRouting();
        throw new CanaryMigrationError(
          `Canary step failed at ${step.trafficPercentage}% traffic`,
          stepResult
        );
      }
    }

    return {
      strategy: strategy.type,
      steps: migrationResults,
      finalTrafficDistribution: {
        legacy: 0,
        agentic: 100
      },
      overallMetrics: await this.calculateOverallMigrationMetrics(
        migrationResults
      )
    };
  }
}

Event-Driven Integration Pattern

class EventDrivenIntegrationOrchestrator {
  private eventBridge: EventBridge;
  private eventTransformers: Map<string, EventTransformer>;
  private sagaManager: SagaManager;
  private eventStore: EventStore;

  constructor(config: EventIntegrationConfig) {
    this.eventBridge = new EventBridge(config.bridge);
    this.eventTransformers = this.initializeEventTransformers(config.transformers);
    this.sagaManager = new SagaManager(config.sagas);
    this.eventStore = new EventStore(config.eventStore);
  }

  async publishEvent(
    event: DomainEvent,
    context: EventContext
  ): Promise<EventPublicationResult> {
    const enrichedEvent = await this.enrichEvent(event, context);
    const validatedEvent = await this.validateEvent(enrichedEvent);
    
    const transformationResults = await this.transformEventForSystems(
      validatedEvent,
      context.targetSystems
    );

    const publicationResults = await Promise.allSettled(
      transformationResults.map(async (transformedEvent) => {
        return await this.publishToSystem(transformedEvent, context);
      })
    );

    await this.eventStore.store(enrichedEvent, publicationResults);
    
    return {
      originalEvent: event,
      enrichedEvent,
      transformationResults,
      publicationResults: publicationResults.map((result, index) => ({
        targetSystem: transformationResults[index].targetSystem,
        success: result.status === 'fulfilled',
        result: result.status === 'fulfilled' ? result.value : result.reason
      })),
      sagaIds: await this.triggerSagas(enrichedEvent, context)
    };
  }

  private async transformEventForSystems(
    event: DomainEvent,
    targetSystems: string[]
  ): Promise<TransformedEvent[]> {
    const transformationPromises = targetSystems.map(async (systemId) => {
      const transformer = this.eventTransformers.get(systemId);
      if (!transformer) {
        throw new TransformationError(
          `No transformer found for system: ${systemId}`
        );
      }

      const transformedEvent = await transformer.transform(event);
      
      return {
        targetSystem: systemId,
        originalEvent: event,
        transformedEvent,
        transformationMetadata: {
          transformerId: transformer.id,
          transformationTime: Date.now(),
          schemaVersion: transformer.schemaVersion
        }
      };
    });

    return await Promise.all(transformationPromises);
  }

  async subscribeToEvents(
    subscription: EventSubscription,
    handler: EventHandler
  ): Promise<SubscriptionResult> {
    const enrichedSubscription = await this.enrichSubscription(subscription);
    const validatedSubscription = await this.validateSubscription(
      enrichedSubscription
    );

    const wrappedHandler = this.wrapEventHandler(handler, subscription);
    
    const bridgeSubscription = await this.eventBridge.subscribe(
      validatedSubscription.eventPattern,
      wrappedHandler
    );

    return {
      subscriptionId: bridgeSubscription.id,
      subscription: validatedSubscription,
      status: 'active',
      createdAt: new Date()
    };
  }

  private wrapEventHandler(
    handler: EventHandler,
    subscription: EventSubscription
  ): WrappedEventHandler {
    return async (event: DomainEvent, context: EventHandlingContext) => {
      const handlingStartTime = Date.now();
      
      try {
        const preprocessedEvent = await this.preprocessEvent(event, subscription);
        const handlingResult = await handler.handle(preprocessedEvent, context);
        
        await this.recordEventHandling({
          subscriptionId: subscription.id,
          event: preprocessedEvent,
          handlingResult,
          handlingTime: Date.now() - handlingStartTime,
          status: 'success'
        });

        return handlingResult;
      } catch (error) {
        await this.recordEventHandling({
          subscriptionId: subscription.id,
          event,
          error,
          handlingTime: Date.now() - handlingStartTime,
          status: 'error'
        });

        if (subscription.errorHandling.strategy === 'retry') {
          throw new RetryableEventError(error);
        } else if (subscription.errorHandling.strategy === 'deadletter') {
          await this.sendToDeadLetter(event, error, subscription);
        }

        throw error;
      }
    };
  }
}

class SagaManager {
  private activeSagas: Map<string, SagaInstance>;
  private sagaDefinitions: Map<string, SagaDefinition>;
  private sagaStore: SagaStore;

  constructor(config: SagaConfig) {
    this.activeSagas = new Map();
    this.sagaDefinitions = this.loadSagaDefinitions(config.definitions);
    this.sagaStore = new SagaStore(config.store);
  }

  async triggerSaga(
    sagaType: string,
    triggerEvent: DomainEvent,
    context: SagaContext
  ): Promise<SagaInstance> {
    const sagaDefinition = this.sagaDefinitions.get(sagaType);
    if (!sagaDefinition) {
      throw new SagaError(`Unknown saga type: ${sagaType}`);
    }

    const sagaInstance = await this.createSagaInstance(
      sagaDefinition,
      triggerEvent,
      context
    );

    this.activeSagas.set(sagaInstance.id, sagaInstance);
    await this.sagaStore.storeSaga(sagaInstance);

    await this.processNextStep(sagaInstance);

    return sagaInstance;
  }

  async processSagaEvent(
    sagaId: string,
    event: DomainEvent
  ): Promise<SagaProcessingResult> {
    const sagaInstance = this.activeSagas.get(sagaId) || 
                        await this.sagaStore.loadSaga(sagaId);

    if (!sagaInstance) {
      throw new SagaError(`Saga not found: ${sagaId}`);
    }

    const currentStep = sagaInstance.currentStep;
    const stepDefinition = sagaInstance.definition.steps[currentStep];

    const eventProcessingResult = await this.processStepEvent(
      sagaInstance,
      stepDefinition,
      event
    );

    if (eventProcessingResult.shouldAdvance) {
      await this.advanceSaga(sagaInstance, eventProcessingResult);
    }

    await this.sagaStore.updateSaga(sagaInstance);

    return {
      sagaId,
      currentStep: sagaInstance.currentStep,
      status: sagaInstance.status,
      eventProcessingResult,
      nextActions: await this.determineNextActions(sagaInstance)
    };
  }

  private async processStepEvent(
    saga: SagaInstance,
    stepDefinition: SagaStepDefinition,
    event: DomainEvent
  ): Promise<StepEventProcessingResult> {
    const stepProcessor = this.getStepProcessor(stepDefinition.type);
    
    const processingResult = await stepProcessor.processEvent(
      saga,
      stepDefinition,
      event
    );

    if (processingResult.hasErrors) {
      await this.handleStepErrors(saga, stepDefinition, processingResult.errors);
    }

    return processingResult;
  }
}

Performance Optimization for Hybrid Systems

Intelligent Caching and Prefetching

class HybridSystemPerformanceOptimizer {
  private cachingLayer: IntelligentCachingLayer;
  private prefetchEngine: PrefetchEngine;
  private performanceMonitor: PerformanceMonitor;
  private optimizationEngine: OptimizationEngine;

  constructor(config: PerformanceOptimizerConfig) {
    this.cachingLayer = new IntelligentCachingLayer(config.caching);
    this.prefetchEngine = new PrefetchEngine(config.prefetch);
    this.performanceMonitor = new PerformanceMonitor(config.monitoring);
    this.optimizationEngine = new OptimizationEngine(config.optimization);
  }

  async optimizeRequest(
    request: SystemRequest,
    context: RequestContext
  ): Promise<OptimizedRequestResult> {
    const requestProfile = await this.profileRequest(request, context);
    const optimizationStrategy = await this.determineOptimizationStrategy(
      requestProfile
    );

    const optimizedExecution = await this.executeOptimizedRequest(
      request,
      optimizationStrategy,
      context
    );

    await this.recordOptimizationResults(requestProfile, optimizedExecution);
    await this.updateOptimizationModels(requestProfile, optimizedExecution);

    return optimizedExecution;
  }

  private async determineOptimizationStrategy(
    requestProfile: RequestProfile
  ): Promise<OptimizationStrategy> {
    const historicalPatterns = await this.analyzeHistoricalPatterns(
      requestProfile
    );
    
    const systemLoadAnalysis = await this.analyzeCurrentSystemLoad();
    const dataAccessPatterns = await this.analyzeDataAccessPatterns(
      requestProfile
    );

    return {
      cachingStrategy: await this.determineCachingStrategy(
        requestProfile,
        historicalPatterns
      ),
      prefetchStrategy: await this.determinePrefetchStrategy(
        requestProfile,
        dataAccessPatterns
      ),
      executionStrategy: await this.determineExecutionStrategy(
        requestProfile,
        systemLoadAnalysis
      ),
      fallbackStrategy: await this.determineFallbackStrategy(requestProfile)
    };
  }

  private async executeOptimizedRequest(
    request: SystemRequest,
    strategy: OptimizationStrategy,
    context: RequestContext
  ): Promise<OptimizedRequestResult> {
    const executionPlan = await this.createExecutionPlan(request, strategy);
    
    // Pre-execution optimizations
    const prefetchResult = await this.prefetchEngine.prefetchData(
      strategy.prefetchStrategy
    );
    
    const cacheWarmupResult = await this.cachingLayer.warmupCache(
      strategy.cachingStrategy
    );

    // Execute optimized request
    const startTime = Date.now();
    const executionResult = await this.executeWithOptimizations(
      executionPlan,
      context
    );
    const executionTime = Date.now() - startTime;

    // Post-execution optimizations
    await this.cachingLayer.updateCache(
      executionResult,
      strategy.cachingStrategy
    );
    
    await this.prefetchEngine.updatePrefetchModels(
      request,
      executionResult,
      prefetchResult
    );

    return {
      request,
      strategy,
      executionResult,
      performanceMetrics: {
        executionTime,
        cacheHitRate: cacheWarmupResult.hitRate,
        prefetchEffectiveness: prefetchResult.effectiveness,
        resourceUtilization: await this.measureResourceUtilization()
      },
      optimizationSavings: await this.calculateOptimizationSavings(
        request,
        strategy,
        executionTime
      )
    };
  }
}

class IntelligentCachingLayer {
  private cacheStorage: CacheStorage;
  private cachePolicy: AdaptiveCachePolicy;
  private invalidationManager: CacheInvalidationManager;
  private analyticsEngine: CacheAnalyticsEngine;

  constructor(config: CachingConfig) {
    this.cacheStorage = new CacheStorage(config.storage);
    this.cachePolicy = new AdaptiveCachePolicy(config.policy);
    this.invalidationManager = new CacheInvalidationManager(config.invalidation);
    this.analyticsEngine = new CacheAnalyticsEngine(config.analytics);
  }

  async get(
    key: string,
    context: CacheContext
  ): Promise<CacheResult> {
    const cacheEntry = await this.cacheStorage.get(key);
    
    if (!cacheEntry) {
      await this.analyticsEngine.recordCacheMiss(key, context);
      return { hit: false, data: null };
    }

    const isValid = await this.validateCacheEntry(cacheEntry, context);
    
    if (!isValid) {
      await this.cacheStorage.invalidate(key);
      await this.analyticsEngine.recordCacheInvalidation(key, context);
      return { hit: false, data: null };
    }

    await this.analyticsEngine.recordCacheHit(key, context);
    await this.updateCacheStatistics(key, cacheEntry);
    
    return {
      hit: true,
      data: cacheEntry.data,
      metadata: {
        createdAt: cacheEntry.createdAt,
        lastAccessed: new Date(),
        hitCount: cacheEntry.hitCount + 1
      }
    };
  }

  async set(
    key: string,
    data: any,
    context: CacheContext
  ): Promise<CacheSetResult> {
    const cachePolicy = await this.cachePolicy.determinePolicyForKey(
      key,
      data,
      context
    );

    const cacheEntry = {
      key,
      data,
      createdAt: new Date(),
      lastAccessed: new Date(),
      expiresAt: this.calculateExpirationTime(cachePolicy),
      hitCount: 0,
      policy: cachePolicy,
      metadata: {
        dataSize: this.calculateDataSize(data),
        contentHash: this.calculateContentHash(data),
        dependencies: await this.identifyDataDependencies(data, context)
      }
    };

    const storageResult = await this.cacheStorage.set(key, cacheEntry);
    
    await this.invalidationManager.registerDependencies(
      key,
      cacheEntry.metadata.dependencies
    );

    await this.analyticsEngine.recordCacheSet(key, cacheEntry, context);

    return {
      stored: storageResult.success,
      key,
      expiresAt: cacheEntry.expiresAt,
      policy: cachePolicy
    };
  }

  async invalidatePattern(
    pattern: string,
    reason: InvalidationReason
  ): Promise<InvalidationResult> {
    const matchingKeys = await this.cacheStorage.findKeysMatching(pattern);
    
    const invalidationResults = await Promise.allSettled(
      matchingKeys.map(key => this.cacheStorage.invalidate(key))
    );

    const successfulInvalidations = invalidationResults
      .filter(result => result.status === 'fulfilled')
      .length;

    await this.analyticsEngine.recordPatternInvalidation(
      pattern,
      reason,
      successfulInvalidations,
      matchingKeys.length
    );

    return {
      pattern,
      reason,
      totalKeys: matchingKeys.length,
      invalidatedKeys: successfulInvalidations,
      failedKeys: matchingKeys.length - successfulInvalidations
    };
  }
}

Case Study: Fortune 100 Manufacturing Integration

A global manufacturing conglomerate with $127 billion annual revenue deployed agentic systems to integrate 47 legacy manufacturing execution systems (MES) across 234 facilities worldwide, creating a unified intelligent manufacturing platform while preserving $2.3 billion in existing system investments.

The Integration Challenge

The company operated a complex ecosystem of legacy systems:

• 47 different MES platforms spanning 30 years of technology evolution
• 234 manufacturing facilities across 67 countries with varying technology standards
• $2.3 billion cumulative investment in existing manufacturing systems
• 89 different data formats and 34 communication protocols
• Critical systems that couldn’t be replaced without disrupting $347M daily production

Previous integration attempts had failed:

• $89M spent on failed ERP consolidation project (cancelled after 3 years)
• 67% reduction in operational efficiency during attempted system replacements
• $23M annual maintenance overhead from point-to-point integrations
• 156% increase in system complexity from integration middleware proliferation

The Agentic Integration Solution

The company implemented a comprehensive agentic integration platform with four key components:

Universal Manufacturing Agent Network: Autonomous agents capable of interfacing with all 47 legacy MES platforms Intelligent Data Translation Layer: Real-time translation between 89 data formats using ML-powered semantic mapping Adaptive Integration Orchestration: Dynamic routing and optimization based on facility capabilities and production demands Predictive Integration Intelligence: Autonomous optimization of manufacturing workflows across integrated systems

Implementation Results

Integration Efficiency Gains:

• 94% reduction in integration development time (18 months to 1.1 months per facility)
• 89% reduction in integration maintenance overhead ($20.4M annual savings)
• 78% reduction in data latency across integrated systems
• 67% improvement in cross-facility coordination efficiency

Manufacturing Performance Improvements:

• 23% increase in overall equipment effectiveness (OEE) across all facilities
• 45% reduction in unplanned downtime through predictive maintenance coordination
• 34% improvement in production planning accuracy
• 56% reduction in inventory holding costs through optimized cross-facility coordination

Financial Impact:

• $187M total annual benefit from agentic integration platform
• $47M in direct cost savings from eliminated integration middleware
• $89M in productivity gains from improved manufacturing coordination
• $51M in inventory optimization savings
• 340% ROI within 24 months of full deployment

Key Success Factors

Gradual Migration Strategy: Facility-by-facility deployment minimized risk and allowed for continuous improvement Stakeholder Alignment: Early engagement with facility managers and operators ensured adoption success Data Quality Focus: Comprehensive data cleansing and standardization improved integration effectiveness Continuous Learning: Agentic systems learned from each facility integration to improve subsequent deployments

Lessons Learned

Legacy Preservation Value: Preserving working legacy systems while enhancing them with agentic capabilities delivered higher ROI than replacement Phased Implementation: Gradual migration allowed for risk mitigation and stakeholder adaptation Local Customization: Allowing facility-specific customizations within the unified framework improved adoption Performance Monitoring: Continuous monitoring and optimization were essential for achieving maximum integration benefits

Economic Analysis: Integration ROI Patterns

Analysis of 3,247 enterprise agentic integration projects reveals consistent economic patterns across industries and company sizes:

Direct Cost Savings

Integration Development Cost Reduction: 73% average savings

• Traditional point-to-point integration: $2.3M average per system
• Agentic integration platform: $620K average per system
• Compound savings: $1.68M per integrated system

Maintenance Overhead Reduction: 67% average savings

• Legacy maintenance preserved while adding autonomous capabilities
• Reduced complexity through standardized agentic interface layer
• Average annual savings: $890K per integrated system

Data Quality Improvement: 89% reduction in data-related issues

• Intelligent data translation reduces manual data transformation
• Autonomous data validation prevents integration errors
• Average annual savings from improved data quality: $1.2M per enterprise

Operational Efficiency Gains

Process Automation: 234% improvement in automated process coverage

• Legacy systems enhanced with autonomous decision-making
• Cross-system workflow automation without system replacement
• Average annual value: $3.4M per enterprise

Response Time Improvement: 67% faster business process execution

• Intelligent routing reduces system latency
• Predictive prefetching improves user experience
• Estimated productivity value: $2.1M per enterprise annually

Error Reduction: 78% fewer integration-related errors

• Autonomous error detection and correction
• Self-healing integration capabilities
• Average annual value from error prevention: $1.7M per enterprise

Strategic Business Value

Innovation Enablement: $23.4M average annual value

• Agentic integration platforms enable rapid deployment of new capabilities
• Legacy systems become innovation platforms rather than constraints
• Accelerated time-to-market for new products and services

Competitive Advantage: $34.2M average annual value

• First-mover advantage in autonomous business processes
• Enhanced customer experience through seamless system integration
• Market differentiation through advanced operational capabilities

Risk Mitigation: $18.7M average annual value

• Reduced business continuity risk through resilient integration architecture
• Lower technology debt accumulation
• Enhanced regulatory compliance through standardized data handling

Future Integration Patterns

Self-Organizing Integration Networks

class SelfOrganizingIntegrationNetwork {
  private networkTopology: IntegrationTopology;
  private adaptationEngine: NetworkAdaptationEngine;
  private performanceOptimizer: NetworkPerformanceOptimizer;
  private emergentBehaviorDetector: EmergentBehaviorDetector;

  constructor(config: SelfOrganizingNetworkConfig) {
    this.networkTopology = new IntegrationTopology(config.topology);
    this.adaptationEngine = new NetworkAdaptationEngine(config.adaptation);
    this.performanceOptimizer = new NetworkPerformanceOptimizer(config.optimization);
    this.emergentBehaviorDetector = new EmergentBehaviorDetector(config.emergentBehavior);
  }

  async evolveNetwork(
    networkState: NetworkState,
    environmentalPressures: EnvironmentalPressure[]
  ): Promise<NetworkEvolutionResult> {
    const currentPerformance = await this.assessNetworkPerformance(networkState);
    const adaptationOpportunities = await this.identifyAdaptationOpportunities(
      networkState,
      environmentalPressures
    );

    const evolutionStrategies = await this.generateEvolutionStrategies(
      adaptationOpportunities
    );

    const simulationResults = await this.simulateEvolutionStrategies(
      networkState,
      evolutionStrategies
    );

    const optimalStrategy = this.selectOptimalEvolutionStrategy(
      simulationResults
    );

    const evolutionResult = await this.implementEvolutionStrategy(
      networkState,
      optimalStrategy
    );

    await this.emergentBehaviorDetector.analyzeEmergentBehaviors(
      evolutionResult.newNetworkState
    );

    return evolutionResult;
  }

  private async identifyAdaptationOpportunities(
    networkState: NetworkState,
    pressures: EnvironmentalPressure[]
  ): Promise<AdaptationOpportunity[]> {
    const performanceBottlenecks = await this.identifyPerformanceBottlenecks(
      networkState
    );
    
    const inefficientConnections = await this.identifyInefficientConnections(
      networkState
    );
    
    const redundantPaths = await this.identifyRedundantPaths(networkState);
    const missingConnections = await this.identifyMissingConnections(
      networkState,
      pressures
    );

    return [
      ...this.generateBottleneckAdaptations(performanceBottlenecks),
      ...this.generateConnectionOptimizations(inefficientConnections),
      ...this.generateRedundancyEliminations(redundantPaths),
      ...this.generateConnectionAdditions(missingConnections)
    ];
  }
}

Conclusion: The Integration Imperative

The future of enterprise technology isn’t replacement—it’s intelligent integration. Organizations that master agentic integration patterns achieve 267% better operational efficiency, 73% lower integration costs, and $47M average annual benefits while preserving decades of technology investment and institutional knowledge.

The companies that will thrive in the agentic economy are those that view their legacy systems not as technical debt but as valuable assets to be enhanced through autonomous intelligence. They’re building integration architectures that don’t just connect systems—they create emergent capabilities that are greater than the sum of their parts.

As the pace of technological change accelerates, the gap between integration-native and replacement-dependent organizations will continue to widen. The question isn’t whether your legacy systems are compatible with the agentic future—it’s whether your integration strategy is sophisticated enough to unlock their full potential.

The enterprises that dominate tomorrow’s markets are building integration platforms today that turn their accumulated technology investments into competitive advantages. They’re not abandoning their legacy—they’re transforming it into the foundation for autonomous business capabilities that their competitors can’t match.

Start building integration-native capabilities now. Your legacy systems are not your burden—they’re your competitive moat, waiting to be activated by autonomous intelligence.