diff --git a/workflow/executor/ts/error-handling/error-recovery.ts b/workflow/executor/ts/error-handling/error-recovery.ts
new file mode 100644
index 000000000..dca461ac4
--- /dev/null
+++ b/workflow/executor/ts/error-handling/error-recovery.ts
@@ -0,0 +1,791 @@
+/**
+ * Error Recovery Manager - Comprehensive Error Handling and Recovery Strategies
+ * Implements error recovery strategies (fallback, skip, retry, fail) with
+ * exponential backoff, metrics tracking, and error state management.
+ * @packageDocumentation
+ */
+
+import {
+  INodeExecutor,
+  WorkflowNode,
+  WorkflowContext,
+  ExecutionState,
+  NodeResult
+} from '../types';
+
+/**
+ * Recovery strategy type
+ */
+export type RecoveryStrategyType = 'fallback' | 'skip' | 'retry' | 'fail';
+
+/**
+ * Error recovery strategy configuration
+ */
+export interface ErrorRecoveryStrategy {
+  strategy: RecoveryStrategyType;
+  fallbackNodeType?: string;
+  maxRetries?: number;
+  retryDelay?: number;
+  retryBackoffMultiplier?: number;
+  maxRetryDelay?: number;
+  retryableErrors?: string[];
+  retryableStatusCodes?: number[];
+  allowPartialOutput?: boolean;
+  notifyOnError?: boolean;
+  notificationChannels?: string[];
+}
+
+/**
+ * Individual error recovery attempt record
+ */
+export interface RecoveryAttempt {
+  timestamp: number;
+  strategy: RecoveryStrategyType;
+  nodeType: string;
+  nodeId: string;
+  attempt: number;
+  maxAttempts: number;
+  error: string;
+  errorType: string;
+  duration: number;
+  status: 'pending' | 'success' | 'failed';
+  output?: any;
+}
+
+/**
+ * Error metrics for tracking and analysis
+ */
+export interface ErrorMetrics {
+  totalErrors: number;
+  recoveryAttempts: number;
+  recoverySuccess: number;
+  recoveryFailed: number;
+  errorsByType: Map<string, number>;
+  errorsByNodeType: Map<string, number>;
+  errorsByStrategy: Map<RecoveryStrategyType, number>;
+  averageRecoveryTime: number;
+  lastErrorTime: number;
+}
+
+/**
+ * Error state for tracking recovery progress
+ */
+export interface ErrorState {
+  nodeId: string;
+  nodeType: string;
+  originalError: Error;
+  errorTime: number;
+  attempts: RecoveryAttempt[];
+  lastAttempt?: RecoveryAttempt;
+  recovered: boolean;
+  finalError?: Error;
+  context?: Record<string, any>;
+}
+
+/**
+ * Recovery result from an attempt
+ */
+export interface RecoveryResult {
+  success: boolean;
+  strategy: RecoveryStrategyType;
+  attempts: number;
+  totalDuration: number;
+  output?: any;
+  error?: string;
+  recoveryAttempts?: RecoveryAttempt[];
+}
+
+/**
+ * Error Recovery Manager Class
+ */
+export class ErrorRecoveryManager {
+  private metrics: ErrorMetrics = {
+    totalErrors: 0,
+    recoveryAttempts: 0,
+    recoverySuccess: 0,
+    recoveryFailed: 0,
+    errorsByType: new Map(),
+    errorsByNodeType: new Map(),
+    errorsByStrategy: new Map(),
+    averageRecoveryTime: 0,
+    lastErrorTime: 0
+  };
+
+  private errorStates: Map<string, ErrorState> = new Map();
+  private recoveryTimes: number[] = [];
+  private readonly MAX_RECOVERY_HISTORY = 1000;
+  private readonly MAX_ERROR_STATES = 500;
+
+  /**
+   * Handle error with recovery strategy
+   */
+  async handleError(
+    nodeType: string,
+    nodeId: string,
+    error: Error,
+    strategy: ErrorRecoveryStrategy,
+    node: WorkflowNode,
+    context: WorkflowContext,
+    state: ExecutionState,
+    registryExecute?: (
+      nodeType: string,
+      node: any,
+      ctx: any,
+      state: any
+    ) => Promise<NodeResult>
+  ): Promise<RecoveryResult> {
+    const startTime = performance.now();
+    this.metrics.totalErrors++;
+    this.metrics.recoveryAttempts++;
+    this.metrics.lastErrorTime = Date.now();
+
+    const errorState = this._createErrorState(nodeType, nodeId, error, context);
+    this._trackError(error, nodeType, strategy.strategy);
+
+    try {
+      switch (strategy.strategy) {
+        case 'fallback':
+          return await this._applyFallback(
+            strategy,
+            node,
+            context,
+            state,
+            registryExecute,
+            errorState,
+            startTime
+          );
+
+        case 'skip':
+          return this._applySkip(errorState, startTime);
+
+        case 'retry':
+          return await this._applyRetry(
+            nodeType,
+            nodeId,
+            node,
+            context,
+            state,
+            strategy,
+            registryExecute,
+            errorState,
+            startTime
+          );
+
+        case 'fail':
+        default:
+          return this._applyFail(error, errorState, startTime);
+      }
+    } catch (recoveryError) {
+      this.metrics.recoveryFailed++;
+      errorState.recovered = false;
+      errorState.finalError = recoveryError as Error;
+      this._storeErrorState(errorState);
+
+      return {
+        success: false,
+        strategy: strategy.strategy,
+        attempts: errorState.attempts.length,
+        totalDuration: performance.now() - startTime,
+        error: `Recovery failed: ${
+          recoveryError instanceof Error
+            ? recoveryError.message
+            : String(recoveryError)
+        }`
+      };
+    }
+  }
+
+  /**
+   * Apply fallback strategy
+   */
+  private async _applyFallback(
+    strategy: ErrorRecoveryStrategy,
+    node: WorkflowNode,
+    context: WorkflowContext,
+    state: ExecutionState,
+    registryExecute: ((
+      nodeType: string,
+      node: any,
+      ctx: any,
+      state: any
+    ) => Promise<NodeResult>) | undefined,
+    errorState: ErrorState,
+    startTime: number
+  ): Promise<RecoveryResult> {
+    if (!strategy.fallbackNodeType || !registryExecute) {
+      return {
+        success: false,
+        strategy: 'fallback',
+        attempts: 0,
+        totalDuration: performance.now() - startTime,
+        error: 'Fallback node type not configured or registry unavailable'
+      };
+    }
+
+    const fallbackStartTime = performance.now();
+
+    try {
+      // Record the attempt
+      const attempt: RecoveryAttempt = {
+        timestamp: Date.now(),
+        strategy: 'fallback',
+        nodeType: strategy.fallbackNodeType,
+        nodeId: node.id,
+        attempt: 1,
+        maxAttempts: 1,
+        error: errorState.originalError.message,
+        errorType: errorState.originalError.constructor.name,
+        duration: 0,
+        status: 'pending'
+      };
+
+      const result = await registryExecute(
+        strategy.fallbackNodeType,
+        node,
+        context,
+        state
+      );
+
+      const duration = performance.now() - fallbackStartTime;
+      attempt.duration = duration;
+      attempt.status = result.status === 'success' ? 'success' : 'failed';
+      attempt.output = result.output;
+
+      errorState.attempts.push(attempt);
+      errorState.lastAttempt = attempt;
+
+      if (result.status === 'success') {
+        this.metrics.recoverySuccess++;
+        errorState.recovered = true;
+        this._storeErrorState(errorState);
+        this._recordRecoveryTime(performance.now() - startTime);
+
+        return {
+          success: true,
+          strategy: 'fallback',
+          attempts: 1,
+          totalDuration: performance.now() - startTime,
+          output: result.output,
+          recoveryAttempts: errorState.attempts
+        };
+      }
+
+      return {
+        success: false,
+        strategy: 'fallback',
+        attempts: 1,
+        totalDuration: performance.now() - startTime,
+        error: `Fallback execution failed: ${result.error}`,
+        recoveryAttempts: errorState.attempts
+      };
+    } catch (fallbackError) {
+      const duration = performance.now() - fallbackStartTime;
+
+      const attempt: RecoveryAttempt = {
+        timestamp: Date.now(),
+        strategy: 'fallback',
+        nodeType: strategy.fallbackNodeType,
+        nodeId: node.id,
+        attempt: 1,
+        maxAttempts: 1,
+        error: fallbackError instanceof Error
+          ? fallbackError.message
+          : String(fallbackError),
+        errorType: fallbackError instanceof Error
+          ? fallbackError.constructor.name
+          : 'UnknownError',
+        duration,
+        status: 'failed'
+      };
+
+      errorState.attempts.push(attempt);
+      errorState.lastAttempt = attempt;
+      errorState.recovered = false;
+      errorState.finalError = fallbackError as Error;
+      this._storeErrorState(errorState);
+
+      return {
+        success: false,
+        strategy: 'fallback',
+        attempts: 1,
+        totalDuration: performance.now() - startTime,
+        error: `Fallback failed: ${
+          fallbackError instanceof Error
+            ? fallbackError.message
+            : String(fallbackError)
+        }`,
+        recoveryAttempts: errorState.attempts
+      };
+    }
+  }
+
+  /**
+   * Apply skip strategy
+   */
+  private _applySkip(
+    errorState: ErrorState,
+    startTime: number
+  ): RecoveryResult {
+    this.metrics.recoverySuccess++;
+
+    const attempt: RecoveryAttempt = {
+      timestamp: Date.now(),
+      strategy: 'skip',
+      nodeType: errorState.nodeType,
+      nodeId: errorState.nodeId,
+      attempt: 1,
+      maxAttempts: 1,
+      error: errorState.originalError.message,
+      errorType: errorState.originalError.constructor.name,
+      duration: 0,
+      status: 'success'
+    };
+
+    errorState.attempts.push(attempt);
+    errorState.lastAttempt = attempt;
+    errorState.recovered = true;
+    this._storeErrorState(errorState);
+    this._recordRecoveryTime(performance.now() - startTime);
+
+    return {
+      success: true,
+      strategy: 'skip',
+      attempts: 1,
+      totalDuration: performance.now() - startTime,
+      output: {},
+      recoveryAttempts: errorState.attempts
+    };
+  }
+
+  /**
+   * Apply retry strategy with exponential backoff
+   */
+  private async _applyRetry(
+    nodeType: string,
+    nodeId: string,
+    node: WorkflowNode,
+    context: WorkflowContext,
+    state: ExecutionState,
+    strategy: ErrorRecoveryStrategy,
+    registryExecute: ((
+      nodeType: string,
+      node: any,
+      ctx: any,
+      state: any
+    ) => Promise<NodeResult>) | undefined,
+    errorState: ErrorState,
+    startTime: number
+  ): Promise<RecoveryResult> {
+    if (!registryExecute) {
+      return {
+        success: false,
+        strategy: 'retry',
+        attempts: 0,
+        totalDuration: performance.now() - startTime,
+        error: 'Registry execute function not available'
+      };
+    }
+
+    const maxRetries = strategy.maxRetries || 3;
+    const initialDelay = strategy.retryDelay || 1000;
+    const backoffMultiplier = strategy.retryBackoffMultiplier || 2;
+    const maxRetryDelay = strategy.maxRetryDelay || 30000;
+
+    let lastError: Error = errorState.originalError;
+    let lastResult: NodeResult | null = null;
+
+    for (let attempt = 1; attempt <= maxRetries; attempt++) {
+      try {
+        // Calculate delay with exponential backoff
+        const delay = this._calculateBackoff(
+          initialDelay,
+          attempt - 1,
+          backoffMultiplier,
+          maxRetryDelay
+        );
+
+        // Wait before retrying
+        await this._delay(delay);
+
+        // Attempt execution
+        const retryStartTime = performance.now();
+        const result = await registryExecute(nodeType, node, context, state);
+        const duration = performance.now() - retryStartTime;
+
+        // Record the attempt
+        const recoveryAttempt: RecoveryAttempt = {
+          timestamp: Date.now(),
+          strategy: 'retry',
+          nodeType: nodeType,
+          nodeId: nodeId,
+          attempt: attempt,
+          maxAttempts: maxRetries,
+          error: lastError.message,
+          errorType: lastError.constructor.name,
+          duration: duration,
+          status: result.status === 'success' ? 'success' : 'failed',
+          output: result.output
+        };
+
+        errorState.attempts.push(recoveryAttempt);
+        errorState.lastAttempt = recoveryAttempt;
+
+        if (result.status === 'success') {
+          this.metrics.recoverySuccess++;
+          errorState.recovered = true;
+          this._storeErrorState(errorState);
+          this._recordRecoveryTime(performance.now() - startTime);
+
+          return {
+            success: true,
+            strategy: 'retry',
+            attempts: attempt,
+            totalDuration: performance.now() - startTime,
+            output: result.output,
+            recoveryAttempts: errorState.attempts
+          };
+        }
+
+        lastResult = result;
+      } catch (retryError) {
+        const duration = performance.now() - startTime;
+
+        // Record failed attempt
+        const recoveryAttempt: RecoveryAttempt = {
+          timestamp: Date.now(),
+          strategy: 'retry',
+          nodeType: nodeType,
+          nodeId: nodeId,
+          attempt: attempt,
+          maxAttempts: maxRetries,
+          error: retryError instanceof Error
+            ? retryError.message
+            : String(retryError),
+          errorType: retryError instanceof Error
+            ? retryError.constructor.name
+            : 'UnknownError',
+          duration: duration,
+          status: 'failed'
+        };
+
+        errorState.attempts.push(recoveryAttempt);
+        errorState.lastAttempt = recoveryAttempt;
+        lastError = retryError as Error;
+
+        // If this is the last attempt, don't continue
+        if (attempt === maxRetries) {
+          errorState.recovered = false;
+          errorState.finalError = retryError as Error;
+          this._storeErrorState(errorState);
+
+          return {
+            success: false,
+            strategy: 'retry',
+            attempts: attempt,
+            totalDuration: performance.now() - startTime,
+            error: `All ${maxRetries} retry attempts failed: ${
+              retryError instanceof Error
+                ? retryError.message
+                : String(retryError)
+            }`,
+            recoveryAttempts: errorState.attempts
+          };
+        }
+      }
+    }
+
+    // Max retries exceeded with no success
+    errorState.recovered = false;
+    errorState.finalError = lastError;
+    this._storeErrorState(errorState);
+
+    return {
+      success: false,
+      strategy: 'retry',
+      attempts: maxRetries,
+      totalDuration: performance.now() - startTime,
+      error: `Max retries (${maxRetries}) exceeded`,
+      recoveryAttempts: errorState.attempts
+    };
+  }
+
+  /**
+   * Apply fail strategy (no recovery attempt)
+   */
+  private _applyFail(
+    error: Error,
+    errorState: ErrorState,
+    startTime: number
+  ): RecoveryResult {
+    errorState.recovered = false;
+    errorState.finalError = error;
+    this._storeErrorState(errorState);
+
+    return {
+      success: false,
+      strategy: 'fail',
+      attempts: 0,
+      totalDuration: performance.now() - startTime,
+      error: error.message
+    };
+  }
+
+  /**
+   * Calculate exponential backoff delay
+   */
+  private _calculateBackoff(
+    initialDelay: number,
+    attemptNumber: number,
+    multiplier: number,
+    maxDelay: number
+  ): number {
+    let delay = initialDelay * Math.pow(multiplier, attemptNumber);
+
+    // Add jitter to prevent thundering herd
+    const jitter = Math.random() * delay * 0.1;
+    delay = Math.min(delay + jitter, maxDelay);
+
+    return Math.round(delay);
+  }
+
+  /**
+   * Delay execution (sleep)
+   */
+  private async _delay(ms: number): Promise<void> {
+    return new Promise((resolve) => setTimeout(resolve, ms));
+  }
+
+  /**
+   * Create error state for tracking
+   */
+  private _createErrorState(
+    nodeType: string,
+    nodeId: string,
+    error: Error,
+    context: WorkflowContext
+  ): ErrorState {
+    return {
+      nodeId,
+      nodeType,
+      originalError: error,
+      errorTime: Date.now(),
+      attempts: [],
+      recovered: false,
+      context: {
+        tenantId: context.tenantId,
+        userId: context.userId,
+        executionId: context.executionId
+      }
+    };
+  }
+
+  /**
+   * Store error state for later analysis
+   */
+  private _storeErrorState(errorState: ErrorState): void {
+    const key = `${errorState.nodeId}-${errorState.errorTime}`;
+    this.errorStates.set(key, errorState);
+
+    // Trim old states if exceeding max
+    if (this.errorStates.size > this.MAX_ERROR_STATES) {
+      const firstKey = this.errorStates.keys().next().value;
+      if (firstKey) {
+        this.errorStates.delete(firstKey);
+      }
+    }
+  }
+
+  /**
+   * Track error occurrence
+   */
+  private _trackError(
+    error: Error,
+    nodeType: string,
+    strategy: RecoveryStrategyType
+  ): void {
+    const errorType = error.constructor.name;
+
+    // Track by error type
+    this.metrics.errorsByType.set(
+      errorType,
+      (this.metrics.errorsByType.get(errorType) || 0) + 1
+    );
+
+    // Track by node type
+    this.metrics.errorsByNodeType.set(
+      nodeType,
+      (this.metrics.errorsByNodeType.get(nodeType) || 0) + 1
+    );
+
+    // Track by recovery strategy
+    this.metrics.errorsByStrategy.set(
+      strategy,
+      (this.metrics.errorsByStrategy.get(strategy) || 0) + 1
+    );
+  }
+
+  /**
+   * Record recovery time
+   */
+  private _recordRecoveryTime(duration: number): void {
+    this.recoveryTimes.push(duration);
+
+    if (this.recoveryTimes.length > this.MAX_RECOVERY_HISTORY) {
+      this.recoveryTimes.shift();
+    }
+
+    // Update average
+    const sum = this.recoveryTimes.reduce((a, b) => a + b, 0);
+    this.metrics.averageRecoveryTime = sum / this.recoveryTimes.length;
+  }
+
+  /**
+   * Get error metrics
+   */
+  getMetrics(): ErrorMetrics {
+    return {
+      ...this.metrics,
+      errorsByType: new Map(this.metrics.errorsByType),
+      errorsByNodeType: new Map(this.metrics.errorsByNodeType),
+      errorsByStrategy: new Map(this.metrics.errorsByStrategy)
+    };
+  }
+
+  /**
+   * Get specific error state by key
+   */
+  getErrorState(nodeId: string, timestamp: number): ErrorState | undefined {
+    const key = `${nodeId}-${timestamp}`;
+    return this.errorStates.get(key);
+  }
+
+  /**
+   * Get all error states for a node
+   */
+  getErrorStatesForNode(nodeId: string): ErrorState[] {
+    return Array.from(this.errorStates.values()).filter(
+      (state) => state.nodeId === nodeId
+    );
+  }
+
+  /**
+   * Get error statistics by type
+   */
+  getErrorStatistics(): {
+    byType: Array<{ type: string; count: number }>;
+    byNodeType: Array<{ nodeType: string; count: number }>;
+    byStrategy: Array<{ strategy: RecoveryStrategyType; count: number }>;
+  } {
+    return {
+      byType: Array.from(this.metrics.errorsByType.entries()).map(
+        ([type, count]) => ({
+          type,
+          count
+        })
+      ),
+      byNodeType: Array.from(this.metrics.errorsByNodeType.entries()).map(
+        ([nodeType, count]) => ({
+          nodeType,
+          count
+        })
+      ),
+      byStrategy: Array.from(this.metrics.errorsByStrategy.entries()).map(
+        ([strategy, count]) => ({
+          strategy,
+          count
+        })
+      )
+    };
+  }
+
+  /**
+   * Clear metrics and state (useful for testing)
+   */
+  clearMetrics(): void {
+    this.metrics = {
+      totalErrors: 0,
+      recoveryAttempts: 0,
+      recoverySuccess: 0,
+      recoveryFailed: 0,
+      errorsByType: new Map(),
+      errorsByNodeType: new Map(),
+      errorsByStrategy: new Map(),
+      averageRecoveryTime: 0,
+      lastErrorTime: 0
+    };
+    this.recoveryTimes = [];
+  }
+
+  /**
+   * Clear error states (useful for memory management)
+   */
+  clearErrorStates(): void {
+    this.errorStates.clear();
+  }
+
+  /**
+   * Get recovery success rate
+   */
+  getRecoverySuccessRate(): number {
+    if (this.metrics.recoveryAttempts === 0) {
+      return 0;
+    }
+
+    return (
+      (this.metrics.recoverySuccess / this.metrics.recoveryAttempts) * 100
+    );
+  }
+
+  /**
+   * Export all metrics for monitoring/logging
+   */
+  exportMetrics(): Record<string, any> {
+    const stats = this.getErrorStatistics();
+
+    return {
+      summary: {
+        totalErrors: this.metrics.totalErrors,
+        recoveryAttempts: this.metrics.recoveryAttempts,
+        recoverySuccess: this.metrics.recoverySuccess,
+        recoveryFailed: this.metrics.recoveryFailed,
+        successRate: this.getRecoverySuccessRate(),
+        averageRecoveryTime: this.metrics.averageRecoveryTime,
+        lastErrorTime: this.metrics.lastErrorTime
+      },
+      statistics: stats,
+      recentErrors: Array.from(this.errorStates.values())
+        .slice(-10)
+        .map((state) => ({
+          nodeId: state.nodeId,
+          nodeType: state.nodeType,
+          error: state.originalError.message,
+          errorType: state.originalError.constructor.name,
+          timestamp: state.errorTime,
+          recovered: state.recovered,
+          attemptCount: state.attempts.length
+        }))
+    };
+  }
+}
+
+/**
+ * Create a singleton instance for global use
+ */
+let globalRecoveryManager: ErrorRecoveryManager | null = null;
+
+/**
+ * Get or create the global error recovery manager
+ */
+export function getErrorRecoveryManager(): ErrorRecoveryManager {
+  if (!globalRecoveryManager) {
+    globalRecoveryManager = new ErrorRecoveryManager();
+  }
+  return globalRecoveryManager;
+}
+
+/**
+ * Reset the global error recovery manager (useful for testing)
+ */
+export function resetErrorRecoveryManager(): void {
+  globalRecoveryManager = null;
+}
diff --git a/workflow/executor/ts/validation/plugin-validator.ts b/workflow/executor/ts/validation/plugin-validator.ts
new file mode 100644
index 000000000..f466fd0a0
--- /dev/null
+++ b/workflow/executor/ts/validation/plugin-validator.ts
@@ -0,0 +1,1023 @@
+/**
+ * Plugin Validator - Schema Validation and Compatibility Checking
+ * Comprehensive validation against plugin metadata, pre-execution checks,
+ * and error type mapping for the workflow executor.
+ * @packageDocumentation
+ */
+
+import {
+  INodeExecutor,
+  WorkflowNode,
+  WorkflowContext,
+  ValidationResult,
+  WorkflowDefinition,
+  RetryPolicy,
+  RateLimitPolicy
+} from '../types';
+
+/**
+ * Plugin metadata schema for validation
+ */
+export interface PluginMetadata {
+  nodeType: string;
+  version: string;
+  category: string;
+  description?: string;
+  requiredFields?: string[];
+  schema?: Record<string, any>;
+  dependencies?: string[];
+  supportedVersions?: string[];
+  tags?: string[];
+  author?: string;
+  icon?: string;
+  experimental?: boolean;
+}
+
+/**
+ * Compatibility check result
+ */
+export interface CompatibilityCheckResult {
+  compatible: boolean;
+  issues: CompatibilityIssue[];
+  warnings: string[];
+}
+
+/**
+ * Individual compatibility issue
+ */
+export interface CompatibilityIssue {
+  type:
+    | 'version-mismatch'
+    | 'missing-dependency'
+    | 'unsupported-feature'
+    | 'schema-violation'
+    | 'credential-mismatch'
+    | 'tenant-restriction';
+  severity: 'error' | 'warning';
+  message: string;
+  details?: Record<string, any>;
+}
+
+/**
+ * Pre-execution validation result
+ */
+export interface PreExecutionValidation {
+  valid: boolean;
+  errors: string[];
+  warnings: string[];
+  parameterValidation: ParameterValidationResult;
+  credentialValidation: CredentialValidationResult;
+  contextValidation: ContextValidationResult;
+}
+
+/**
+ * Parameter validation result
+ */
+export interface ParameterValidationResult {
+  valid: boolean;
+  missingRequired: string[];
+  invalidTypes: ParameterTypeError[];
+  schemaViolations: string[];
+}
+
+/**
+ * Parameter type error
+ */
+export interface ParameterTypeError {
+  field: string;
+  expected: string;
+  received: string;
+  value: any;
+}
+
+/**
+ * Credential validation result
+ */
+export interface CredentialValidationResult {
+  valid: boolean;
+  missingCredentials: string[];
+  invalidCredentials: string[];
+  expiredCredentials: string[];
+}
+
+/**
+ * Context validation result
+ */
+export interface ContextValidationResult {
+  valid: boolean;
+  errors: string[];
+  missingContext: string[];
+}
+
+/**
+ * Error type classification
+ */
+export enum ErrorType {
+  VALIDATION_ERROR = 'VALIDATION_ERROR',
+  SCHEMA_VIOLATION = 'SCHEMA_VIOLATION',
+  TYPE_MISMATCH = 'TYPE_MISMATCH',
+  MISSING_REQUIRED = 'MISSING_REQUIRED',
+  INCOMPATIBLE_VERSION = 'INCOMPATIBLE_VERSION',
+  CREDENTIAL_ERROR = 'CREDENTIAL_ERROR',
+  CONTEXT_ERROR = 'CONTEXT_ERROR',
+  DEPENDENCY_ERROR = 'DEPENDENCY_ERROR',
+  TIMEOUT_ERROR = 'TIMEOUT_ERROR',
+  EXECUTION_ERROR = 'EXECUTION_ERROR',
+  UNKNOWN_ERROR = 'UNKNOWN_ERROR'
+}
+
+/**
+ * Mapped error for structured error handling
+ */
+export interface MappedError {
+  type: ErrorType;
+  message: string;
+  originalError: Error;
+  isRecoverable: boolean;
+  suggestedAction?: string;
+  context?: Record<string, any>;
+}
+
+/**
+ * Plugin Validator Class
+ * Provides comprehensive validation for plugins before execution
+ */
+export class PluginValidator {
+  private metadataCache: Map<string, PluginMetadata> = new Map();
+  private schemaCache: Map<string, any> = new Map();
+  private readonly MAX_PARAMETER_SIZE = 10 * 1024 * 1024; // 10MB
+  private readonly MAX_OUTPUT_SIZE = 50 * 1024 * 1024; // 50MB
+
+  /**
+   * Register plugin metadata for validation
+   */
+  registerMetadata(metadata: PluginMetadata): void {
+    if (!this._validateMetadataFormat(metadata)) {
+      throw new Error(`Invalid metadata for plugin: ${metadata.nodeType}`);
+    }
+
+    this.metadataCache.set(metadata.nodeType, metadata);
+  }
+
+  /**
+   * Get registered metadata for a plugin
+   */
+  getMetadata(nodeType: string): PluginMetadata | undefined {
+    return this.metadataCache.get(nodeType);
+  }
+
+  /**
+   * Full schema validation against plugin metadata
+   */
+  validateSchema(nodeType: string, node: WorkflowNode): ValidationResult {
+    const errors: string[] = [];
+    const warnings: string[] = [];
+
+    const metadata = this.metadataCache.get(nodeType);
+    if (!metadata) {
+      return {
+        valid: false,
+        errors: [`No metadata registered for node type: ${nodeType}`],
+        warnings: []
+      };
+    }
+
+    // Check required fields
+    if (metadata.requiredFields) {
+      const missingFields = metadata.requiredFields.filter(
+        (field) => !(field in node.parameters)
+      );
+
+      if (missingFields.length > 0) {
+        errors.push(`Missing required fields: ${missingFields.join(', ')}`);
+      }
+    }
+
+    // Validate against JSON schema if present
+    if (metadata.schema) {
+      const schemaErrors = this._validateAgainstJsonSchema(
+        node.parameters,
+        metadata.schema
+      );
+      errors.push(...schemaErrors);
+    }
+
+    // Validate parameter types
+    const typeErrors = this._validateParameterTypes(node.parameters, metadata);
+    if (typeErrors.length > 0) {
+      errors.push(...typeErrors);
+    }
+
+    // Check for deprecated parameters
+    const deprecationWarnings = this._checkDeprecatedParameters(
+      node.parameters,
+      metadata
+    );
+    warnings.push(...deprecationWarnings);
+
+    // Validate parameter sizes
+    const sizeErrors = this._validateParameterSizes(node.parameters);
+    errors.push(...sizeErrors);
+
+    return {
+      valid: errors.length === 0,
+      errors,
+      warnings
+    };
+  }
+
+  /**
+   * Check plugin compatibility with workflow environment
+   */
+  checkCompatibility(
+    nodeType: string,
+    node: WorkflowNode,
+    context: WorkflowContext,
+    workflow: WorkflowDefinition
+  ): CompatibilityCheckResult {
+    const issues: CompatibilityIssue[] = [];
+    const warnings: string[] = [];
+
+    const metadata = this.metadataCache.get(nodeType);
+    if (!metadata) {
+      return {
+        compatible: false,
+        issues: [
+          {
+            type: 'schema-violation',
+            severity: 'error',
+            message: `No metadata registered for node type: ${nodeType}`
+          }
+        ],
+        warnings: []
+      };
+    }
+
+    // Check version compatibility
+    const versionIssue = this._checkVersionCompatibility(
+      metadata,
+      workflow.version
+    );
+    if (versionIssue) {
+      issues.push(versionIssue);
+    }
+
+    // Check dependencies
+    const depIssues = this._checkDependencies(metadata);
+    issues.push(...depIssues);
+
+    // Check tenant restrictions
+    const tenantIssue = this._checkTenantRestrictions(
+      metadata,
+      context.tenantId
+    );
+    if (tenantIssue) {
+      issues.push(tenantIssue);
+    }
+
+    // Check credential requirements
+    const credentialIssues = this._checkCredentialRequirements(
+      metadata,
+      node,
+      context
+    );
+    issues.push(...credentialIssues);
+
+    // Check feature support
+    const featureIssues = this._checkFeatureSupport(metadata, node);
+    issues.push(...featureIssues);
+
+    const compatible = issues.filter((i) => i.severity === 'error').length === 0;
+
+    return {
+      compatible,
+      issues,
+      warnings
+    };
+  }
+
+  /**
+   * Comprehensive pre-execution validation
+   */
+  validatePreExecution(
+    nodeType: string,
+    node: WorkflowNode,
+    context: WorkflowContext,
+    executor?: INodeExecutor
+  ): PreExecutionValidation {
+    const errors: string[] = [];
+    const warnings: string[] = [];
+
+    // 1. Validate executor interface
+    if (executor) {
+      const executorValidation = this._validateExecutorInterface(executor);
+      if (!executorValidation.valid) {
+        errors.push(...executorValidation.errors);
+      }
+    }
+
+    // 2. Validate parameters
+    const paramValidation = this._validateNodeParameters(
+      node,
+      this.metadataCache.get(nodeType)
+    );
+    if (!paramValidation.valid) {
+      errors.push(...paramValidation.schemaViolations);
+      warnings.push(
+        ...paramValidation.missingRequired.map(
+          (f) => `Missing recommended field: ${f}`
+        )
+      );
+    }
+
+    // 3. Validate credentials
+    const credentialValidation = this._validateCredentials(node, context);
+    if (!credentialValidation.valid) {
+      errors.push(...credentialValidation.missingCredentials);
+      warnings.push(...credentialValidation.expiredCredentials);
+    }
+
+    // 4. Validate context
+    const contextValidation = this._validateExecutionContext(node, context);
+    if (!contextValidation.valid) {
+      errors.push(...contextValidation.errors);
+    }
+
+    // 5. Validate timeout settings
+    const timeoutWarnings = this._validateTimeout(node);
+    warnings.push(...timeoutWarnings);
+
+    // 6. Validate retry policy
+    if (node.retryPolicy) {
+      const retryWarnings = this._validateRetryPolicy(node.retryPolicy);
+      warnings.push(...retryWarnings);
+    }
+
+    return {
+      valid: errors.length === 0,
+      errors,
+      warnings,
+      parameterValidation: paramValidation,
+      credentialValidation: credentialValidation,
+      contextValidation: contextValidation
+    };
+  }
+
+  /**
+   * Map error types to structured error objects
+   */
+  mapErrorType(error: Error, context?: Record<string, any>): MappedError {
+    const errorMessage = error.message.toLowerCase();
+
+    // Type mismatches
+    if (
+      errorMessage.includes('type') ||
+      errorMessage.includes('expected') ||
+      errorMessage.includes('received')
+    ) {
+      return {
+        type: ErrorType.TYPE_MISMATCH,
+        message: error.message,
+        originalError: error,
+        isRecoverable: false,
+        suggestedAction: 'Check parameter types in node configuration',
+        context
+      };
+    }
+
+    // Validation errors
+    if (
+      errorMessage.includes('validation') ||
+      errorMessage.includes('invalid') ||
+      errorMessage.includes('schema')
+    ) {
+      return {
+        type: ErrorType.VALIDATION_ERROR,
+        message: error.message,
+        originalError: error,
+        isRecoverable: false,
+        suggestedAction: 'Fix node parameters to match schema',
+        context
+      };
+    }
+
+    // Missing required fields
+    if (
+      errorMessage.includes('required') ||
+      errorMessage.includes('missing')
+    ) {
+      return {
+        type: ErrorType.MISSING_REQUIRED,
+        message: error.message,
+        originalError: error,
+        isRecoverable: false,
+        suggestedAction: 'Add missing required parameters',
+        context
+      };
+    }
+
+    // Credential errors
+    if (
+      errorMessage.includes('credential') ||
+      errorMessage.includes('unauthorized') ||
+      errorMessage.includes('authentication')
+    ) {
+      return {
+        type: ErrorType.CREDENTIAL_ERROR,
+        message: error.message,
+        originalError: error,
+        isRecoverable: true,
+        suggestedAction: 'Check credential configuration and permissions',
+        context
+      };
+    }
+
+    // Version compatibility
+    if (
+      errorMessage.includes('version') ||
+      errorMessage.includes('compatible')
+    ) {
+      return {
+        type: ErrorType.INCOMPATIBLE_VERSION,
+        message: error.message,
+        originalError: error,
+        isRecoverable: true,
+        suggestedAction: 'Update plugin or workflow to compatible version',
+        context
+      };
+    }
+
+    // Dependency errors
+    if (
+      errorMessage.includes('dependency') ||
+      errorMessage.includes('not found') ||
+      errorMessage.includes('require')
+    ) {
+      return {
+        type: ErrorType.DEPENDENCY_ERROR,
+        message: error.message,
+        originalError: error,
+        isRecoverable: true,
+        suggestedAction: 'Install missing dependencies',
+        context
+      };
+    }
+
+    // Timeout errors
+    if (
+      errorMessage.includes('timeout') ||
+      errorMessage.includes('timed out')
+    ) {
+      return {
+        type: ErrorType.TIMEOUT_ERROR,
+        message: error.message,
+        originalError: error,
+        isRecoverable: true,
+        suggestedAction: 'Increase timeout or optimize node execution',
+        context
+      };
+    }
+
+    // Context errors
+    if (
+      errorMessage.includes('context') ||
+      errorMessage.includes('tenantid') ||
+      errorMessage.includes('userid')
+    ) {
+      return {
+        type: ErrorType.CONTEXT_ERROR,
+        message: error.message,
+        originalError: error,
+        isRecoverable: false,
+        suggestedAction: 'Check execution context configuration',
+        context
+      };
+    }
+
+    // Default to execution error
+    return {
+      type: ErrorType.EXECUTION_ERROR,
+      message: error.message,
+      originalError: error,
+      isRecoverable: true,
+      suggestedAction: 'Review execution logs and node configuration',
+      context
+    };
+  }
+
+  /**
+   * Validate all plugins in batch
+   */
+  validateAllRegisteredMetadata(): Array<{ nodeType: string; valid: boolean; errors: string[] }> {
+    const results: Array<{ nodeType: string; valid: boolean; errors: string[] }> = [];
+
+    for (const [nodeType, metadata] of this.metadataCache) {
+      const errors: string[] = [];
+
+      if (!metadata.version) {
+        errors.push('Missing version');
+      }
+
+      if (!metadata.category) {
+        errors.push('Missing category');
+      }
+
+      if (!metadata.nodeType) {
+        errors.push('Missing nodeType');
+      }
+
+      results.push({
+        nodeType,
+        valid: errors.length === 0,
+        errors
+      });
+    }
+
+    return results;
+  }
+
+  /**
+   * Clear all cached metadata
+   */
+  clearCache(): void {
+    this.metadataCache.clear();
+    this.schemaCache.clear();
+  }
+
+  // ===== Private Methods =====
+
+  /**
+   * Validate metadata format
+   */
+  private _validateMetadataFormat(metadata: any): boolean {
+    if (!metadata || typeof metadata !== 'object') {
+      return false;
+    }
+
+    // Check required fields
+    if (!metadata.nodeType || typeof metadata.nodeType !== 'string') {
+      return false;
+    }
+
+    if (!metadata.version || typeof metadata.version !== 'string') {
+      return false;
+    }
+
+    if (!metadata.category || typeof metadata.category !== 'string') {
+      return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Validate against JSON schema
+   */
+  private _validateAgainstJsonSchema(data: any, schema: any): string[] {
+    const errors: string[] = [];
+
+    // Simple JSON schema validation (subset)
+    if (schema.type) {
+      if (schema.type === 'object' && typeof data !== 'object') {
+        errors.push(`Expected object, received ${typeof data}`);
+      }
+      if (schema.type === 'array' && !Array.isArray(data)) {
+        errors.push(`Expected array, received ${typeof data}`);
+      }
+    }
+
+    // Check required properties
+    if (schema.required && Array.isArray(schema.required)) {
+      for (const prop of schema.required) {
+        if (!(prop in data)) {
+          errors.push(`Missing required property: ${prop}`);
+        }
+      }
+    }
+
+    // Validate properties against schema
+    if (schema.properties && typeof schema.properties === 'object') {
+      for (const [key, propSchema] of Object.entries(schema.properties)) {
+        if (key in data) {
+          const propErrors = this._validateProperty(
+            data[key],
+            propSchema as any
+          );
+          errors.push(...propErrors);
+        }
+      }
+    }
+
+    return errors;
+  }
+
+  /**
+   * Validate individual property
+   */
+  private _validateProperty(value: any, schema: any): string[] {
+    const errors: string[] = [];
+
+    if (schema.type) {
+      if (schema.type === 'string' && typeof value !== 'string') {
+        errors.push(`Expected string, received ${typeof value}`);
+      }
+      if (schema.type === 'number' && typeof value !== 'number') {
+        errors.push(`Expected number, received ${typeof value}`);
+      }
+      if (schema.type === 'boolean' && typeof value !== 'boolean') {
+        errors.push(`Expected boolean, received ${typeof value}`);
+      }
+    }
+
+    if (schema.minimum !== undefined && value < schema.minimum) {
+      errors.push(`Value ${value} is below minimum ${schema.minimum}`);
+    }
+
+    if (schema.maximum !== undefined && value > schema.maximum) {
+      errors.push(`Value ${value} exceeds maximum ${schema.maximum}`);
+    }
+
+    if (schema.enum && !schema.enum.includes(value)) {
+      errors.push(`Value must be one of: ${schema.enum.join(', ')}`);
+    }
+
+    return errors;
+  }
+
+  /**
+   * Validate parameter types
+   */
+  private _validateParameterTypes(
+    parameters: Record<string, any>,
+    metadata: PluginMetadata
+  ): string[] {
+    const errors: string[] = [];
+
+    if (!metadata.schema || !metadata.schema.properties) {
+      return errors;
+    }
+
+    for (const [key, value] of Object.entries(parameters)) {
+      const propSchema = metadata.schema.properties[key];
+      if (!propSchema) continue;
+
+      if (propSchema.type) {
+        const actualType = Array.isArray(value) ? 'array' : typeof value;
+        if (propSchema.type !== actualType) {
+          errors.push(
+            `Parameter '${key}': expected ${propSchema.type}, got ${actualType}`
+          );
+        }
+      }
+    }
+
+    return errors;
+  }
+
+  /**
+   * Check for deprecated parameters
+   */
+  private _checkDeprecatedParameters(
+    parameters: Record<string, any>,
+    metadata: PluginMetadata
+  ): string[] {
+    const warnings: string[] = [];
+
+    if (!metadata.schema || !metadata.schema.deprecated) {
+      return warnings;
+    }
+
+    const deprecated = metadata.schema.deprecated as string[];
+    for (const key of deprecated) {
+      if (key in parameters) {
+        warnings.push(`Parameter '${key}' is deprecated`);
+      }
+    }
+
+    return warnings;
+  }
+
+  /**
+   * Validate parameter sizes
+   */
+  private _validateParameterSizes(parameters: Record<string, any>): string[] {
+    const errors: string[] = [];
+
+    for (const [key, value] of Object.entries(parameters)) {
+      if (typeof value === 'string' && value.length > this.MAX_PARAMETER_SIZE) {
+        errors.push(
+          `Parameter '${key}' exceeds maximum size of ${this.MAX_PARAMETER_SIZE} bytes`
+        );
+      }
+    }
+
+    return errors;
+  }
+
+  /**
+   * Check version compatibility
+   */
+  private _checkVersionCompatibility(
+    metadata: PluginMetadata,
+    workflowVersion: string
+  ): CompatibilityIssue | null {
+    if (!metadata.supportedVersions || metadata.supportedVersions.length === 0) {
+      return null;
+    }
+
+    if (!metadata.supportedVersions.includes(workflowVersion)) {
+      return {
+        type: 'version-mismatch',
+        severity: 'warning',
+        message: `Plugin ${metadata.nodeType} v${metadata.version} may not be compatible with workflow v${workflowVersion}`,
+        details: {
+          pluginVersion: metadata.version,
+          supportedWorkflowVersions: metadata.supportedVersions,
+          workflowVersion
+        }
+      };
+    }
+
+    return null;
+  }
+
+  /**
+   * Check dependencies
+   */
+  private _checkDependencies(metadata: PluginMetadata): CompatibilityIssue[] {
+    const issues: CompatibilityIssue[] = [];
+
+    if (!metadata.dependencies || metadata.dependencies.length === 0) {
+      return issues;
+    }
+
+    for (const dep of metadata.dependencies) {
+      // This would check if dependencies are installed
+      // For now, we mark as potential issues
+      issues.push({
+        type: 'missing-dependency',
+        severity: 'warning',
+        message: `Dependency '${dep}' required by ${metadata.nodeType}`,
+        details: { dependency: dep }
+      });
+    }
+
+    return issues;
+  }
+
+  /**
+   * Check tenant restrictions
+   */
+  private _checkTenantRestrictions(
+    metadata: PluginMetadata,
+    tenantId: string
+  ): CompatibilityIssue | null {
+    // Check if plugin has tenant restrictions
+    // This would be defined in metadata or elsewhere
+    if (metadata.experimental) {
+      return {
+        type: 'tenant-restriction',
+        severity: 'warning',
+        message: `Plugin ${metadata.nodeType} is experimental and may have limited support`,
+        details: { experimental: true }
+      };
+    }
+
+    return null;
+  }
+
+  /**
+   * Check credential requirements
+   */
+  private _checkCredentialRequirements(
+    metadata: PluginMetadata,
+    node: WorkflowNode,
+    context: WorkflowContext
+  ): CompatibilityIssue[] {
+    const issues: CompatibilityIssue[] = [];
+
+    // Check if node requires credentials but doesn't have them
+    if (
+      Object.keys(node.credentials).length === 0 &&
+      metadata.schema?.required?.some((r: string) => r.includes('credential'))
+    ) {
+      issues.push({
+        type: 'credential-mismatch',
+        severity: 'error',
+        message: `Plugin ${metadata.nodeType} requires credentials but none are configured`,
+        details: { nodeId: node.id }
+      });
+    }
+
+    return issues;
+  }
+
+  /**
+   * Check feature support
+   */
+  private _checkFeatureSupport(
+    metadata: PluginMetadata,
+    node: WorkflowNode
+  ): CompatibilityIssue[] {
+    const issues: CompatibilityIssue[] = [];
+
+    // Check if node uses unsupported features
+    if (node.disabled) {
+      // Disabled nodes are fine, just noted
+    }
+
+    return issues;
+  }
+
+  /**
+   * Validate executor interface
+   */
+  private _validateExecutorInterface(executor: INodeExecutor): ValidationResult {
+    const errors: string[] = [];
+
+    if (typeof executor.execute !== 'function') {
+      errors.push('Executor missing execute method');
+    }
+
+    if (typeof executor.validate !== 'function') {
+      errors.push('Executor missing validate method');
+    }
+
+    if (!executor.nodeType) {
+      errors.push('Executor missing nodeType');
+    }
+
+    return {
+      valid: errors.length === 0,
+      errors,
+      warnings: []
+    };
+  }
+
+  /**
+   * Validate node parameters
+   */
+  private _validateNodeParameters(
+    node: WorkflowNode,
+    metadata?: PluginMetadata
+  ): ParameterValidationResult {
+    const missingRequired: string[] = [];
+    const invalidTypes: ParameterTypeError[] = [];
+    const schemaViolations: string[] = [];
+
+    if (!metadata) {
+      return { valid: true, missingRequired, invalidTypes, schemaViolations };
+    }
+
+    if (metadata.requiredFields) {
+      for (const field of metadata.requiredFields) {
+        if (!(field in node.parameters)) {
+          missingRequired.push(field);
+        }
+      }
+    }
+
+    return {
+      valid: missingRequired.length === 0 && invalidTypes.length === 0,
+      missingRequired,
+      invalidTypes,
+      schemaViolations
+    };
+  }
+
+  /**
+   * Validate credentials
+   */
+  private _validateCredentials(
+    node: WorkflowNode,
+    context: WorkflowContext
+  ): CredentialValidationResult {
+    const missingCredentials: string[] = [];
+    const invalidCredentials: string[] = [];
+    const expiredCredentials: string[] = [];
+
+    for (const [credKey, credRef] of Object.entries(node.credentials)) {
+      if (!credRef.id) {
+        missingCredentials.push(credKey);
+      }
+
+      // Check if credential is in context
+      if (!context.secrets || !(credKey in context.secrets)) {
+        invalidCredentials.push(credKey);
+      }
+    }
+
+    return {
+      valid:
+        missingCredentials.length === 0 &&
+        invalidCredentials.length === 0 &&
+        expiredCredentials.length === 0,
+      missingCredentials,
+      invalidCredentials,
+      expiredCredentials
+    };
+  }
+
+  /**
+   * Validate execution context
+   */
+  private _validateExecutionContext(
+    node: WorkflowNode,
+    context: WorkflowContext
+  ): ContextValidationResult {
+    const errors: string[] = [];
+    const missingContext: string[] = [];
+
+    if (!context.executionId) {
+      missingContext.push('executionId');
+    }
+
+    if (!context.tenantId) {
+      missingContext.push('tenantId');
+    }
+
+    if (!context.userId) {
+      missingContext.push('userId');
+    }
+
+    if (!context.trigger) {
+      missingContext.push('trigger');
+    }
+
+    if (missingContext.length > 0) {
+      errors.push(`Missing context: ${missingContext.join(', ')}`);
+    }
+
+    return {
+      valid: errors.length === 0,
+      errors,
+      missingContext
+    };
+  }
+
+  /**
+   * Validate timeout settings
+   */
+  private _validateTimeout(node: WorkflowNode): string[] {
+    const warnings: string[] = [];
+
+    if (!node.timeout && node.timeout !== 0) {
+      warnings.push('Node has no timeout configured (will use default)');
+    }
+
+    if (node.timeout && node.timeout < 1000) {
+      warnings.push(
+        `Node timeout ${node.timeout}ms is very short, may cause failures`
+      );
+    }
+
+    return warnings;
+  }
+
+  /**
+   * Validate retry policy
+   */
+  private _validateRetryPolicy(policy: RetryPolicy): string[] {
+    const warnings: string[] = [];
+
+    if (!policy.enabled) {
+      return warnings;
+    }
+
+    if (policy.maxAttempts < 1) {
+      warnings.push('Retry policy has invalid maxAttempts < 1');
+    }
+
+    if (policy.initialDelay < 0) {
+      warnings.push('Retry policy has negative initialDelay');
+    }
+
+    if (policy.maxDelay < policy.initialDelay) {
+      warnings.push('Retry policy maxDelay is less than initialDelay');
+    }
+
+    return warnings;
+  }
+}
+
+/**
+ * Create a singleton instance for global use
+ */
+let globalValidator: PluginValidator | null = null;
+
+/**
+ * Get or create the global plugin validator
+ */
+export function getPluginValidator(): PluginValidator {
+  if (!globalValidator) {
+    globalValidator = new PluginValidator();
+  }
+  return globalValidator;
+}
+
+/**
+ * Reset the global validator (useful for testing)
+ */
+export function resetPluginValidator(): void {
+  globalValidator = null;
+}