diff --git a/src/lib/entitySubmissionHelpers.ts b/src/lib/entitySubmissionHelpers.ts
index 9cb1c597..8989393c 100644
--- a/src/lib/entitySubmissionHelpers.ts
+++ b/src/lib/entitySubmissionHelpers.ts
@@ -8,6 +8,7 @@ import type { CompanyDatabaseRecord, TimelineEventDatabaseRecord } from '@/types
 import { logger } from './logger';
 import { handleError } from './errorHandler';
 import type { TimelineEventFormData, EntityType } from '@/types/timeline';
+import { breadcrumb } from './errorBreadcrumbs';
 import { 
   validateParkCreateFields, 
   validateRideCreateFields, 
@@ -202,57 +203,106 @@ async function submitCompositeCreation(
   dependencies: CompositeSubmissionDependency[],
   userId: string
 ): Promise<{ submitted: boolean; submissionId: string }> {
-  // Check if user is banned
-  const { data: profile } = await supabase
-    .from('profiles')
-    .select('banned')
-    .eq('user_id', userId)
-    .single();
+  try {
+    breadcrumb.userAction('Start composite submission', 'submitCompositeCreation', {
+      primaryType: primaryEntity.type,
+      dependencyCount: dependencies.length,
+      userId
+    });
 
-  if (profile?.banned) {
-    throw new Error('Account suspended. Contact support for assistance.');
-  }
+    // Check if user is banned
+    breadcrumb.apiCall('profiles', 'SELECT');
+    try {
+      const { data: profile, error } = await supabase
+        .from('profiles')
+        .select('banned')
+        .eq('user_id', userId)
+        .single();
 
-  // Upload all pending images for all entities
-  const uploadedEntities = await Promise.all([
-    ...dependencies.map(async (dep) => {
-      if (dep.data.images?.uploaded && dep.data.images.uploaded.length > 0) {
-        const uploadedImages = await uploadPendingImages(dep.data.images.uploaded);
-        return {
-          ...dep,
-          data: {
-            ...dep.data,
-            images: { ...dep.data.images, uploaded: uploadedImages }
-          }
-        };
+      if (error) {
+        throw new Error(`Failed to check user status: ${error.message}`);
       }
-      return dep;
-    }),
-    (async () => {
-      if (primaryEntity.data.images?.uploaded && primaryEntity.data.images.uploaded.length > 0) {
-        const uploadedImages = await uploadPendingImages(primaryEntity.data.images.uploaded);
-        return {
-          ...primaryEntity,
-          data: {
-            ...primaryEntity.data,
-            images: { ...primaryEntity.data.images, uploaded: uploadedImages }
-          }
-        };
+
+      if (profile?.banned) {
+        throw new Error('Account suspended. Contact support for assistance.');
       }
-      return primaryEntity;
-    })()
-  ]);
+    } catch (error) {
+      throw error instanceof Error ? error : new Error(`User check failed: ${String(error)}`);
+    }
 
-  const uploadedDependencies = uploadedEntities.slice(0, -1) as CompositeSubmissionDependency[];
-  const uploadedPrimary = uploadedEntities[uploadedEntities.length - 1] as typeof primaryEntity;
+    // Upload all pending images for all entities
+    breadcrumb.userAction('Upload images', 'submitCompositeCreation', {
+      totalImages: dependencies.reduce((sum, dep) => sum + (dep.data.images?.uploaded?.length || 0), 0) + 
+                   (primaryEntity.data.images?.uploaded?.length || 0)
+    });
 
-  // Build submission items array with dependencies first
-  const submissionItems: any[] = [];
-  const tempIdMap = new Map<string, number>(); // Maps tempId to order_index
+    const uploadedEntities = await Promise.all([
+      ...dependencies.map(async (dep, index) => {
+        try {
+          if (dep.data.images?.uploaded && dep.data.images.uploaded.length > 0) {
+            const uploadedImages = await uploadPendingImages(dep.data.images.uploaded);
+            return {
+              ...dep,
+              data: {
+                ...dep.data,
+                images: { ...dep.data.images, uploaded: uploadedImages }
+              }
+            };
+          }
+          return dep;
+        } catch (error) {
+          const errorMsg = error instanceof Error ? error.message : String(error);
+          throw new Error(
+            `Failed to upload images for ${dep.type} "${dep.data.name || 'unnamed'}": ${errorMsg}`
+          );
+        }
+      }),
+      (async () => {
+        try {
+          if (primaryEntity.data.images?.uploaded && primaryEntity.data.images.uploaded.length > 0) {
+            const uploadedImages = await uploadPendingImages(primaryEntity.data.images.uploaded);
+            return {
+              ...primaryEntity,
+              data: {
+                ...primaryEntity.data,
+                images: { ...primaryEntity.data.images, uploaded: uploadedImages }
+              }
+            };
+          }
+          return primaryEntity;
+        } catch (error) {
+          const errorMsg = error instanceof Error ? error.message : String(error);
+          throw new Error(
+            `Failed to upload images for ${primaryEntity.type} "${primaryEntity.data.name || 'unnamed'}": ${errorMsg}`
+          );
+        }
+      })()
+    ]);
 
-  // Add dependency items (companies, models) first
-  let orderIndex = 0;
-  for (const dep of uploadedDependencies) {
+    const uploadedDependencies = uploadedEntities.slice(0, -1) as CompositeSubmissionDependency[];
+    const uploadedPrimary = uploadedEntities[uploadedEntities.length - 1] as typeof primaryEntity;
+
+    // Validate dependencies structure
+    breadcrumb.stateChange('Validating dependencies', {
+      dependencyCount: uploadedDependencies.length
+    });
+
+    for (const dep of uploadedDependencies) {
+      if (!dep.type) throw new Error('Dependency missing type');
+      if (!dep.tempId) throw new Error('Dependency missing tempId');
+      if (!dep.data) throw new Error('Dependency missing data');
+      if (dep.type === 'company' && !dep.companyType) {
+        throw new Error(`Company dependency "${dep.data.name || 'unnamed'}" missing companyType`);
+      }
+    }
+
+    // Build submission items array with dependencies first
+    const submissionItems: any[] = [];
+    const tempIdMap = new Map<string, number>(); // Maps tempId to order_index
+
+    // Add dependency items (companies, models) first
+    let orderIndex = 0;
+    for (const dep of uploadedDependencies) {
     const itemType = dep.type === 'company' ? dep.companyType : dep.type;
     tempIdMap.set(dep.tempId, orderIndex);
     
@@ -370,11 +420,12 @@ async function submitCompositeCreation(
     }
   }
 
-  // Use RPC to create submission with items atomically with retry logic
-  const { withRetry } = await import('./retryHelpers');
-  const { toast } = await import('@/hooks/use-toast');
-  
-  const result = await withRetry(
+    // Use RPC to create submission with items atomically with retry logic
+    breadcrumb.apiCall('create_submission_with_items', 'RPC');
+    const { withRetry } = await import('./retryHelpers');
+    const { toast } = await import('@/hooks/use-toast');
+    
+    const result = await withRetry(
     async () => {
       const { data, error } = await supabase.rpc('create_submission_with_items', {
         p_user_id: userId,
@@ -446,24 +497,41 @@ async function submitCompositeCreation(
         return isRetryableError(error);
       }
     }
-  ).catch((error) => {
-    // Final failure - log and throw
-    handleError(error, {
-      action: 'Composite submission',
-      metadata: { 
-        primaryType: uploadedPrimary.type, 
-        dependencyCount: dependencies.length,
-        supabaseCode: (error as any).supabaseCode,
-        supabaseDetails: (error as any).supabaseDetails,
-        supabaseHint: (error as any).supabaseHint,
-        retriesExhausted: true
-      },
+    ).catch((error) => {
+      // Final failure - log and throw
+      handleError(error, {
+        action: 'Composite submission',
+        metadata: { 
+          primaryType: uploadedPrimary.type, 
+          dependencyCount: dependencies.length,
+          supabaseCode: (error as any).supabaseCode,
+          supabaseDetails: (error as any).supabaseDetails,
+          supabaseHint: (error as any).supabaseHint,
+          retriesExhausted: true
+        },
+      });
+      
+      throw error;
     });
-    
-    throw error;
-  });
 
-  return { submitted: true, submissionId: result };
+    breadcrumb.stateChange('Composite submission successful', {
+      submissionId: result
+    });
+
+    return { submitted: true, submissionId: result };
+  } catch (error) {
+    // Ensure error is always an Error instance with context
+    const enrichedError = error instanceof Error 
+      ? error 
+      : new Error(`Composite submission failed: ${String(error)}`);
+    
+    // Attach metadata for better debugging
+    (enrichedError as any).originalError = error;
+    (enrichedError as any).primaryType = primaryEntity?.type;
+    (enrichedError as any).dependencyCount = dependencies?.length;
+    
+    throw enrichedError;
+  }
 }
 
 /**
diff --git a/src/lib/errorHandler.ts b/src/lib/errorHandler.ts
index 8154c46a..d24f1d51 100644
--- a/src/lib/errorHandler.ts
+++ b/src/lib/errorHandler.ts
@@ -34,6 +34,7 @@ export const handleError = (
   let errorMessage: string;
   let stack: string | undefined;
   let errorName = 'UnknownError';
+  let supabaseErrorDetails: Record<string, any> | undefined;
   
   if (error instanceof Error) {
     errorMessage = error instanceof AppError 
@@ -41,6 +42,15 @@ export const handleError = (
       : error.message;
     stack = error.stack;
     errorName = error.name;
+    
+    // Check if Error instance has attached Supabase metadata
+    if ((error as any).supabaseCode) {
+      supabaseErrorDetails = {
+        code: (error as any).supabaseCode,
+        details: (error as any).supabaseDetails,
+        hint: (error as any).supabaseHint
+      };
+    }
   } else if (error && typeof error === 'object') {
     // Handle Supabase errors (plain objects with message/code/details)
     const supabaseError = error as { 
@@ -48,13 +58,24 @@ export const handleError = (
       code?: string; 
       details?: string; 
       hint?: string;
+      stack?: string;
     };
     
     errorMessage = supabaseError.message || 'An unexpected error occurred';
     errorName = 'SupabaseError';
     
-    // Create synthetic stack trace for Supabase errors to aid debugging
-    if (supabaseError.code || supabaseError.details || supabaseError.hint) {
+    // Capture Supabase error details for metadata
+    supabaseErrorDetails = {
+      code: supabaseError.code,
+      details: supabaseError.details,
+      hint: supabaseError.hint
+    };
+    
+    // Try to extract stack from object
+    if (supabaseError.stack && typeof supabaseError.stack === 'string') {
+      stack = supabaseError.stack;
+    } else if (supabaseError.code || supabaseError.details || supabaseError.hint) {
+      // Create synthetic stack trace for Supabase errors to aid debugging
       const stackParts = [
         `SupabaseError: ${errorMessage}`,
         supabaseError.code ? `  Code: ${supabaseError.code}` : null,
@@ -68,8 +89,12 @@ export const handleError = (
     }
   } else if (typeof error === 'string') {
     errorMessage = error;
+    // Generate synthetic stack trace for string errors
+    stack = new Error().stack?.replace(/^Error\n/, `StringError: ${error}\n`);
   } else {
     errorMessage = 'An unexpected error occurred';
+    // Generate synthetic stack trace for unknown error types
+    stack = new Error().stack?.replace(/^Error\n/, `UnknownError: ${String(error)}\n`);
   }
 
   // Log to console/monitoring with enhanced debugging
@@ -84,6 +109,7 @@ export const handleError = (
     errorConstructor: error?.constructor?.name,
     hasStack: !!stack,
     isSyntheticStack: !!(error && typeof error === 'object' && !(error instanceof Error) && stack),
+    supabaseError: supabaseErrorDetails,
   });
   
   // Additional debug logging when stack is missing
@@ -114,11 +140,13 @@ export const handleError = (
       p_error_stack: stack,
       p_user_agent: navigator.userAgent,
       p_breadcrumbs: JSON.stringify({
-        ...breadcrumbs,
+        breadcrumbs,
         isRetry: context.metadata?.isRetry || false,
         attempt: context.metadata?.attempt,
         retriesExhausted: context.metadata?.retriesExhausted || false,
         circuitBreakerState: context.metadata?.circuitState,
+        supabaseError: supabaseErrorDetails,
+        metadata: context.metadata
       }),
       p_timezone: envContext.timezone,
       p_referrer: document.referrer || undefined,