Agent Orchestration

Advanced coordination patterns for managing complex workflows, resource allocation, and performance optimization in multi-agent systems.

Overview

Agent orchestration involves coordinating multiple agents to work together efficiently on complex tasks. This includes workflow management, resource allocation, conflict resolution, and performance optimization.

Orchestration Patterns

Workflow Orchestration

class WorkflowOrchestrator
{
    private array $agents = [];
    private WorkflowEngine $engine;
    private ResourceManager $resourceManager;

    public function executeWorkflow(Workflow $workflow): WorkflowResult
    {
        echo "🔄 Starting workflow: {$workflow->name}\n";

        try {
            // Validate workflow
            $this->validateWorkflow($workflow);

            // Allocate resources
            $resources = $this->resourceManager->allocateResources($workflow);

            // Execute workflow steps
            $results = [];
            foreach ($workflow->steps as $step) {
                $result = $this->executeWorkflowStep($step, $resources);
                $results[] = $result;

                // Check for early termination conditions
                if (!$result->success && $step->critical) {
                    throw new WorkflowException("Critical step failed: {$step->name}");
                }
            }

            return new WorkflowResult(true, 'Workflow completed successfully', $results);

        } catch (\Exception $e) {
            echo "❌ Workflow failed: {$e->getMessage()}\n";

            // Cleanup and rollback if needed
            $this->cleanupWorkflow($workflow, $resources ?? []);

            return new WorkflowResult(false, $e->getMessage());
        } finally {
            // Release allocated resources
            if (isset($resources)) {
                $this->resourceManager->releaseResources($resources);
            }
        }
    }

    private function executeWorkflowStep(WorkflowStep $step, array $resources): StepResult
    {
        echo "  ⚙️ Executing step: {$step->name}\n";

        // Select appropriate agent for this step
        $agent = $this->selectAgentForStep($step);

        if (!$agent) {
            throw new WorkflowException("No suitable agent found for step: {$step->name}");
        }

        // Prepare step context
        $context = new StepContext(
            $step,
            $resources,
            $this->getWorkflowState()
        );

        // Execute step with timeout
        $startTime = microtime(true);

        try {
            $result = $this->executeStepWithTimeout($agent, $context, $step->timeout ?? 30);
            $duration = microtime(true) - $startTime;

            echo "    ✅ Step completed in " . round($duration, 2) . "s\n";

            return new StepResult(true, $result, $duration);

        } catch (\Exception $e) {
            $duration = microtime(true) - $startTime;

            echo "    ❌ Step failed after " . round($duration, 2) . "s: {$e->getMessage()}\n";

            return new StepResult(false, $e->getMessage(), $duration);
        }
    }

    private function selectAgentForStep(WorkflowStep $step): ?Agent
    {
        // Score agents based on capability match
        $scores = [];

        foreach ($this->agents as $agentId => $agent) {
            $score = $this->calculateAgentScore($agent, $step);

            if ($score > 0) {
                $scores[$agentId] = $score;
            }
        }

        if (empty($scores)) {
            return null;
        }

        // Select agent with highest score
        arsort($scores);
        $bestAgentId = array_key_first($scores);

        return $this->agents[$bestAgentId];
    }

    private function calculateAgentScore(Agent $agent, WorkflowStep $step): float
    {
        $score = 0.0;

        // Capability match score
        $agentCapabilities = $agent->getCapabilities();
        $requiredCapabilities = $step->requiredCapabilities;

        $matchCount = count(array_intersect($agentCapabilities, $requiredCapabilities));
        $score += ($matchCount / count($requiredCapabilities)) * 0.4;

        // Performance score
        $performance = $agent->getPerformanceMetrics();
        $score += $performance->successRate * 0.3;
        $score += (1 - $performance->averageResponseTime / 10) * 0.2; // Favor faster agents

        // Availability score
        $score += $agent->isAvailable() ? 0.1 : 0.0;

        return $score;
    }
}

Resource Management

class ResourceManager
{
    private array $resources = [];
    private array $allocations = [];
    private array $reservations = [];

    public function allocateResources(Workflow $workflow): array
    {
        $allocation = [];

        foreach ($workflow->resourceRequirements as $requirement) {
            $resource = $this->findAvailableResource($requirement);

            if (!$resource) {
                throw new ResourceException("Required resource not available: {$requirement->type}");
            }

            $this->reserveResource($resource->id, $workflow->id);
            $allocation[$requirement->name] = $resource;
        }

        $this->allocations[$workflow->id] = $allocation;

        return $allocation;
    }

    public function releaseResources(array $resources): void
    {
        foreach ($resources as $resource) {
            $this->releaseResource($resource->id);
        }
    }

    private function findAvailableResource(ResourceRequirement $requirement): ?Resource
    {
        foreach ($this->resources as $resource) {
            if ($resource->type === $requirement->type &&
                $resource->isAvailable() &&
                $this->meetsRequirements($resource, $requirement)) {
                return $resource;
            }
        }

        return null;
    }

    private function meetsRequirements(Resource $resource, ResourceRequirement $requirement): bool
    {
        // Check if resource meets all requirements
        foreach ($requirement->specifications as $spec => $value) {
            if (!$resource->hasSpecification($spec, $value)) {
                return false;
            }
        }

        return true;
    }
}

Task Queue Management

class DistributedTaskQueue
{
    private array $queues = [];
    private TaskScheduler $scheduler;
    private PriorityCalculator $priorityCalculator;

    public function enqueueTask(Task $task): void
    {
        // Calculate task priority
        $priority = $this->priorityCalculator->calculate($task);
        $task->priority = $priority;

        // Determine appropriate queue
        $queueId = $this->selectQueue($task);

        if (!isset($this->queues[$queueId])) {
            $this->queues[$queueId] = new PriorityQueue();
        }

        $this->queues[$queueId]->insert($task, $priority);

        echo "📥 Task {$task->id} queued in {$queueId} with priority {$priority}\n";
    }

    public function processQueues(): void
    {
        async(function () {
            while (true) {
                foreach ($this->queues as $queueId => $queue) {
                    if (!$queue->isEmpty()) {
                        $task = $queue->extract();
                        $this->processTask($task, $queueId);
                    }
                }

                delay(1000)->await(); // Check every second
            }
        })->await();
    }

    private function processTask(Task $task, string $queueId): void
    {
        echo "⚙️ Processing task {$task->id} from queue {$queueId}\n";

        try {
            // Find available agent for this task
            $agent = $this->findAvailableAgent($task->requiredCapabilities);

            if (!$agent) {
                // Re-queue task for later
                $this->enqueueTask($task);
                return;
            }

            // Execute task
            $result = $agent->executeTask($task);

            if ($result->success) {
                echo "  ✅ Task {$task->id} completed successfully\n";
            } else {
                echo "  ❌ Task {$task->id} failed: {$result->error}\n";

                // Handle task failure (retry, escalate, etc.)
                $this->handleTaskFailure($task, $result);
            }

        } catch (\Exception $e) {
            echo "  💥 Task {$task->id} crashed: {$e->getMessage()}\n";
            $this->handleTaskCrash($task, $e);
        }
    }
}

Advanced Orchestration Features

Dynamic Agent Scaling

class AutoScalingOrchestrator
{
    private array $agentPools = [];
    private MetricsCollector $metrics;
    private ScalingPolicy $scalingPolicy;

    public function autoScale(): void
    {
        foreach ($this->agentPools as $poolId => $pool) {
            $metrics = $this->metrics->getPoolMetrics($poolId);
            $decision = $this->scalingPolicy->shouldScale($metrics);

            if ($decision->action === 'scale_up') {
                $this->scaleUp($poolId, $decision->targetCount);
            } elseif ($decision->action === 'scale_down') {
                $this->scaleDown($poolId, $decision->targetCount);
            }
        }
    }

    private function scaleUp(string $poolId, int $targetCount): void
    {
        $currentCount = count($this->agentPools[$poolId]);
        $newAgents = $targetCount - $currentCount;

        echo "📈 Scaling up {$poolId} pool: adding {$newAgents} agents\n";

        for ($i = 0; $i < $newAgents; $i++) {
            $agent = $this->createAgent($poolId);
            $this->agentPools[$poolId][] = $agent;
        }
    }

    private function scaleDown(string $poolId, int $targetCount): void
    {
        $currentCount = count($this->agentPools[$poolId]);
        $removeCount = $currentCount - $targetCount;

        echo "📉 Scaling down {$poolId} pool: removing {$removeCount} agents\n";

        // Remove least active agents
        $agents = $this->agentPools[$poolId];
        usort($agents, fn($a, $b) => $a->getActivityScore() <=> $b->getActivityScore());

        for ($i = 0; $i < $removeCount; $i++) {
            $agent = array_shift($agents);
            $agent->shutdown();
        }

        $this->agentPools[$poolId] = $agents;
    }
}

Circuit Breaker for Agent Communication

class AgentCircuitBreaker
{
    private array $circuitStates = [];
    private int $failureThreshold = 5;
    private int $recoveryTimeout = 60;

    public function callAgent(string $agentId, callable $operation): mixed
    {
        $circuitKey = "agent:{$agentId}";

        if ($this->isCircuitOpen($circuitKey)) {
            throw new CircuitBreakerException("Circuit breaker open for agent {$agentId}");
        }

        try {
            $result = $operation();
            $this->recordSuccess($circuitKey);
            return $result;

        } catch (\Exception $e) {
            $this->recordFailure($circuitKey);
            throw $e;
        }
    }

    private function isCircuitOpen(string $circuitKey): bool
    {
        $state = $this->circuitStates[$circuitKey] ?? null;

        if (!$state) {
            return false;
        }

        if ($state['failures'] >= $this->failureThreshold) {
            if (time() - $state['last_failure'] > $this->recoveryTimeout) {
                // Try to recover
                unset($this->circuitStates[$circuitKey]);
                return false;
            }
            return true;
        }

        return false;
    }
}

Complete Orchestration Example

Customer Service Agent System

class CustomerServiceOrchestrator
{
    private TriageAgent $triageAgent;
    private TechnicalSupportAgent $techAgent;
    private BillingAgent $billingAgent;
    private EscalationAgent $escalationAgent;
    private QualityAssuranceAgent $qaAgent;

    public function handleCustomerInquiry(CustomerInquiry $inquiry): ServiceResult
    {
        echo "📞 Handling customer inquiry: {$inquiry->id}\n";

        try {
            // Step 1: Triage the inquiry
            $triage = $this->triageAgent->categorizeInquiry($inquiry);
            echo "🏷️ Inquiry categorized as: {$triage->category} (confidence: {$triage->confidence})\n";

            // Step 2: Route to appropriate specialist agent
            $specialist = $this->selectSpecialistAgent($triage);
            echo "👤 Routing to specialist: {$specialist->getName()}\n";

            // Step 3: Process with specialist
            $resolution = $specialist->processInquiry($inquiry, $triage);

            // Step 4: Quality check
            $qaResult = $this->qaAgent->reviewResolution($inquiry, $resolution);

            if ($qaResult->needsEscalation) {
                echo "⬆️ Escalating to senior agent\n";
                $resolution = $this->escalationAgent->handleEscalation($inquiry, $resolution, $qaResult);
            }

            // Step 5: Follow up
            $this->scheduleFollowUp($inquiry, $resolution);

            echo "✅ Customer inquiry {$inquiry->id} resolved successfully\n";

            return new ServiceResult(true, $resolution, [
                'triage' => $triage,
                'specialist' => $specialist->getName(),
                'qa_score' => $qaResult->score
            ]);

        } catch (\Exception $e) {
            echo "❌ Failed to handle inquiry {$inquiry->id}: {$e->getMessage()}\n";

            // Automatic escalation for system failures
            $this->escalationAgent->handleSystemFailure($inquiry, $e);

            return new ServiceResult(false, "System error: {$e->getMessage()}");
        }
    }

    private function selectSpecialistAgent(TriageResult $triage): Agent
    {
        return match($triage->category) {
            'technical_issue' => $this->techAgent,
            'billing_question' => $this->billingAgent,
            'account_management' => $this->accountAgent,
            'product_inquiry' => $this->productAgent,
            default => $this->generalAgent
        };
    }
}

Resource Allocation Engine

class ResourceAllocationEngine
{
    private array $resources = [];
    private array $allocations = [];
    private AllocationStrategy $strategy;

    public function allocateOptimal(array $tasks, array $agents): AllocationPlan
    {
        // Use optimization algorithm to find best allocation
        $plan = $this->strategy->optimize($tasks, $agents, $this->resources);

        // Validate allocation is feasible
        if (!$this->validateAllocation($plan)) {
            throw new AllocationException('Optimal allocation not feasible with current resources');
        }

        return $plan;
    }

    public function executeAllocation(AllocationPlan $plan): AllocationResult
    {
        $results = [];
        $promises = [];

        foreach ($plan->assignments as $assignment) {
            $promises[] = async(function () use ($assignment) {
                try {
                    // Allocate resources to agent
                    $this->allocateResourcesToAgent($assignment->agent, $assignment->resources);

                    // Execute task
                    $result = $assignment->agent->executeTask($assignment->task);

                    return new AssignmentResult(true, $result);

                } catch (\Exception $e) {
                    return new AssignmentResult(false, $e->getMessage());
                } finally {
                    // Release resources
                    $this->releaseResourcesFromAgent($assignment->agent, $assignment->resources);
                }
            });
        }

        $results = Promise::all($promises)->await();

        return new AllocationResult(
            $this->calculateSuccessRate($results),
            $results
        );
    }
}

Performance Monitoring

class OrchestrationMonitor
{
    private MetricsCollector $metrics;
    private AlertManager $alerts;
    private PerformanceAnalyzer $analyzer;

    public function startMonitoring(): void
    {
        async(function () {
            while (true) {
                // Collect metrics from all agents
                $metrics = $this->collectAgentMetrics();

                // Analyze performance
                $analysis = $this->analyzer->analyze($metrics);

                // Check for performance issues
                $this->checkPerformanceThresholds($analysis);

                // Generate recommendations
                $recommendations = $this->generateOptimizationRecommendations($analysis);

                if (!empty($recommendations)) {
                    echo "💡 Performance recommendations:\n";
                    foreach ($recommendations as $rec) {
                        echo "  - {$rec}\n";
                    }
                }

                delay(30000)->await(); // Monitor every 30 seconds
            }
        })->await();
    }

    private function collectAgentMetrics(): array
    {
        $metrics = [];

        foreach ($this->getMonitoredAgents() as $agentId => $agent) {
            try {
                $agentMetrics = $agent->getMetrics();
                $metrics[$agentId] = [
                    'response_time' => $agentMetrics->averageResponseTime,
                    'success_rate' => $agentMetrics->successRate,
                    'throughput' => $agentMetrics->tasksPerMinute,
                    'error_rate' => $agentMetrics->errorRate,
                    'memory_usage' => $agentMetrics->memoryUsage,
                    'cpu_usage' => $agentMetrics->cpuUsage
                ];
            } catch (\Exception $e) {
                $metrics[$agentId] = ['error' => $e->getMessage()];
            }
        }

        return $metrics;
    }

    private function checkPerformanceThresholds(PerformanceAnalysis $analysis): void
    {
        // Check response time threshold
        if ($analysis->averageResponseTime > 5.0) {
            $this->alerts->trigger('high_response_time', [
                'current' => $analysis->averageResponseTime,
                'threshold' => 5.0
            ]);
        }

        // Check error rate threshold
        if ($analysis->errorRate > 0.05) { // 5%
            $this->alerts->trigger('high_error_rate', [
                'current' => $analysis->errorRate,
                'threshold' => 0.05
            ]);
        }

        // Check resource utilization
        if ($analysis->resourceUtilization > 0.9) { // 90%
            $this->alerts->trigger('high_resource_usage', [
                'current' => $analysis->resourceUtilization,
                'threshold' => 0.9
            ]);
        }
    }
}

Conflict Resolution

Conflict Detection and Resolution

class ConflictResolver
{
    private array $conflictStrategies = [];

    public function detectConflicts(array $agentActions): array
    {
        $conflicts = [];

        // Check for resource conflicts
        $resourceUsage = [];
        foreach ($agentActions as $action) {
            foreach ($action->requiredResources as $resource) {
                if (!isset($resourceUsage[$resource])) {
                    $resourceUsage[$resource] = [];
                }
                $resourceUsage[$resource][] = $action;
            }
        }

        foreach ($resourceUsage as $resource => $actions) {
            if (count($actions) > 1) {
                $conflicts[] = new ResourceConflict($resource, $actions);
            }
        }

        // Check for logical conflicts
        $conflicts = array_merge($conflicts, $this->detectLogicalConflicts($agentActions));

        return $conflicts;
    }

    public function resolveConflicts(array $conflicts): ResolutionPlan
    {
        $resolutions = [];

        foreach ($conflicts as $conflict) {
            $strategy = $this->selectResolutionStrategy($conflict);
            $resolution = $strategy->resolve($conflict);
            $resolutions[] = $resolution;
        }

        return new ResolutionPlan($resolutions);
    }

    private function selectResolutionStrategy(Conflict $conflict): ConflictResolutionStrategy
    {
        return match($conflict->type) {
            'resource_conflict' => new ResourcePriorityStrategy(),
            'logical_conflict' => new LogicalResolutionStrategy(),
            'timing_conflict' => new TemporalResolutionStrategy(),
            default => new DefaultResolutionStrategy()
        };
    }
}

Complete Orchestration Example

E-commerce Fulfillment System

class EcommerceFulfillmentOrchestrator
{
    private WorkflowOrchestrator $workflowOrchestrator;
    private ResourceManager $resourceManager;
    private ConflictResolver $conflictResolver;
    private PerformanceMonitor $monitor;

    public function fulfillOrder(Order $order): FulfillmentResult
    {
        echo "🎯 Starting order fulfillment for order {$order->id}\n";

        // Create fulfillment workflow
        $workflow = $this->createFulfillmentWorkflow($order);

        // Check for conflicts with other orders
        $conflicts = $this->conflictResolver->detectConflicts(
            $this->getCurrentWorkflows()
        );

        if (!empty($conflicts)) {
            echo "⚠️ Conflicts detected, resolving...\n";
            $resolutionPlan = $this->conflictResolver->resolveConflicts($conflicts);
            $this->applyResolutionPlan($resolutionPlan);
        }

        // Execute workflow with monitoring
        $this->monitor->startWorkflowMonitoring($workflow->id);

        try {
            $result = $this->workflowOrchestrator->executeWorkflow($workflow);

            $this->monitor->recordWorkflowCompletion($workflow->id, $result);

            return new FulfillmentResult(
                $result->success,
                "Order {$order->id} " . ($result->success ? 'fulfilled' : 'failed'),
                $result->data
            );

        } catch (\Exception $e) {
            $this->monitor->recordWorkflowFailure($workflow->id, $e);
            throw $e;
        }
    }

    private function createFulfillmentWorkflow(Order $order): Workflow
    {
        $steps = [
            new WorkflowStep('inventory_check', 'Check inventory availability'),
            new WorkflowStep('payment_processing', 'Process payment'),
            new WorkflowStep('inventory_reservation', 'Reserve inventory'),
            new WorkflowStep('picking_list', 'Generate picking list'),
            new WorkflowStep('packaging', 'Package items'),
            new WorkflowStep('shipping_label', 'Create shipping label'),
            new WorkflowStep('dispatch', 'Dispatch for delivery'),
            new WorkflowStep('tracking_notification', 'Send tracking notification')
        ];

        return new Workflow("fulfillment_{$order->id}", $steps);
    }
}

Best Practices

1. Orchestration Design

• Workflow Modeling: Model complex processes as clear workflows
• Resource Planning: Plan resource allocation before execution
• Failure Handling: Design for graceful degradation
• Performance Monitoring: Continuously monitor orchestration performance

2. Agent Coordination

• Clear Interfaces: Define clear agent communication protocols
• Timeout Management: Implement proper timeouts for all operations
• State Synchronization: Keep agent states synchronized
• Conflict Prevention: Design to minimize conflicts

3. Scalability

• Horizontal Scaling: Design for adding more agents
• Load Distribution: Distribute work evenly
• Resource Optimization: Optimize resource usage
• Performance Tuning: Continuously tune for better performance

4. Reliability

• Fault Tolerance: Handle individual agent failures
• Recovery Mechanisms: Implement automatic recovery
• Data Consistency: Ensure data consistency across agents
• Audit Trails: Maintain complete audit trails

See Also

• Building AI Agents - Individual agent development
• Multi-Agent Systems - Agent coordination basics
• Best Practices - Production patterns
• Enterprise Examples - Production deployments