final tweak

packages/ai/src/utils/message-conversion.ts

@@ -67,10 +67,24 @@ export function convertCoreMessageToModelMessage(message: unknown): ModelMessage
     case 'tool':
       // Tool messages are always arrays of ToolResultPart
       if (Array.isArray(content)) {
+        // Convert and flatten nested results
+        const convertedContent = [];
+        for (const part of content) {
+          const converted = convertToolResultPart(part);
+          if (converted !== null) {
+            if (Array.isArray(converted)) {
+              // Flatten nested arrays (from wrapper tool results)
+              convertedContent.push(...converted);
+            } else {
+              convertedContent.push(converted);
+            }
+          }
+        }
+
         return {
           role: 'tool',
           // biome-ignore lint/suspicious/noExplicitAny: necessary for v4 to v5 conversion
-          content: content.map(convertToolResultPart) as any,
+          content: convertedContent as any,
         };
       }
 
@@ -134,7 +148,7 @@ function convertContentPart(part: unknown): unknown {
 /**
  * Convert tool result parts from v4 to v5 format
  */
-function convertToolResultPart(part: unknown): unknown {
+function convertToolResultPart(part: unknown): unknown | unknown[] | null {
   if (!part || typeof part !== 'object') {
     return part;
   }
@@ -145,10 +159,54 @@ function convertToolResultPart(part: unknown): unknown {
     return part;
   }
 
+  // Check if this is a wrapper with empty toolCallId/toolName and nested results
+  if (
+    'toolCallId' in p &&
+    (p.toolCallId === '' || !p.toolCallId) &&
+    'toolName' in p &&
+    (p.toolName === '' || !p.toolName) &&
+    'result' in p &&
+    Array.isArray(p.result)
+  ) {
+    // This is a wrapper - extract and convert the nested tool results
+    const nestedResults = [];
+    for (const nestedItem of p.result) {
+      if (
+        nestedItem &&
+        typeof nestedItem === 'object' &&
+        'type' in nestedItem &&
+        nestedItem.type === 'tool-result'
+      ) {
+        const converted = convertToolResultPart(nestedItem);
+        if (converted !== null) {
+          if (Array.isArray(converted)) {
+            nestedResults.push(...converted);
+          } else {
+            nestedResults.push(converted);
+          }
+        }
+      }
+    }
+    // Return the array of nested results to be flattened
+    return nestedResults.length > 0 ? nestedResults : null;
+  }
+
   // Convert result → output with proper structure
   if ('result' in p && !('output' in p)) {
     const { result, experimental_content, isError, ...rest } = p;
 
+    // Ensure toolCallId exists and is valid
+    // If it's missing or invalid, skip this result
+    if (!rest.toolCallId || typeof rest.toolCallId !== 'string' || rest.toolCallId.trim() === '') {
+      return null;
+    }
+
+    // Check if toolCallId matches the required pattern
+    const validPattern = /^[a-zA-Z0-9_-]+$/;
+    if (!validPattern.test(rest.toolCallId as string)) {
+      return null;
+    }
+
     // Convert result to structured output format
     let output: { type: string; value: unknown };
     if (isError) {
@@ -167,12 +225,6 @@ function convertToolResultPart(part: unknown): unknown {
       }
     }
 
-    // Ensure toolCallId exists and is valid
-    // If it's missing or invalid, preserve the original part
-    if (!rest.toolCallId || typeof rest.toolCallId !== 'string') {
-      return part;
-    }
-
     return {
       ...rest,
       output,

packages/database/src/queries/messages/chatConversationHistory.ts

@@ -67,9 +67,23 @@ export function convertCoreToModel(messages: unknown): ModelMessage[] {
       case 'tool':
         // Tool messages: convert result to structured output
         if (Array.isArray(content)) {
+          // Convert and flatten nested results
+          const convertedContent = [];
+          for (const part of content) {
+            const converted = convertToolResultPart(part);
+            if (converted !== null) {
+              if (Array.isArray(converted)) {
+                // Flatten nested arrays (from wrapper tool results)
+                convertedContent.push(...converted);
+              } else {
+                convertedContent.push(converted);
+              }
+            }
+          }
+
           return {
             ...msg,
-            content: content.map(convertToolResultPart),
+            content: convertedContent,
           } as ModelMessage;
         }
         return { role: 'tool', content: [] } as ModelMessage;
@@ -133,7 +147,7 @@ function convertContentPart(part: unknown): unknown {
 /**
  * Convert tool result parts from v4 to v5 format
  */
-function convertToolResultPart(part: unknown): unknown {
+function convertToolResultPart(part: unknown): unknown | unknown[] | null {
   if (!part || typeof part !== 'object') {
     return part;
   }
@@ -144,10 +158,64 @@ function convertToolResultPart(part: unknown): unknown {
     return part;
   }
 
-  // Convert result → structured output
+  // Check if this is a wrapper with empty toolCallId/toolName and nested results
+  if (
+    'toolCallId' in p &&
+    (p.toolCallId === '' || !p.toolCallId) &&
+    'toolName' in p &&
+    (p.toolName === '' || !p.toolName) &&
+    'result' in p &&
+    Array.isArray(p.result)
+  ) {
+    // This is a wrapper - extract and convert the nested tool results
+    const nestedResults = [];
+    for (const nestedItem of p.result) {
+      if (
+        nestedItem &&
+        typeof nestedItem === 'object' &&
+        'type' in nestedItem &&
+        nestedItem.type === 'tool-result'
+      ) {
+        const converted = convertToolResultPart(nestedItem);
+        if (converted !== null) {
+          if (Array.isArray(converted)) {
+            nestedResults.push(...converted);
+          } else {
+            nestedResults.push(converted);
+          }
+        }
+      }
+    }
+    // Return the array of nested results to be flattened
+    return nestedResults.length > 0 ? nestedResults : null;
+  }
+
+  // Only convert if we have 'result' field but not 'output' (v4 format)
   if ('result' in p && !('output' in p)) {
     const { result, experimental_content, isError, ...rest } = p;
 
+    // Validate toolCallId exists and matches Anthropic's pattern
+    const toolCallId = rest.toolCallId;
+    if (!toolCallId || typeof toolCallId !== 'string' || toolCallId.trim() === '') {
+      console.warn('[chatConversationHistory] Skipping tool-result with invalid toolCallId:', {
+        toolCallId,
+        toolName: rest.toolName,
+      });
+      // Skip this tool result entirely if toolCallId is invalid
+      return null;
+    }
+
+    // Check if toolCallId matches the required pattern
+    const validPattern = /^[a-zA-Z0-9_-]+$/;
+    if (!validPattern.test(toolCallId)) {
+      console.warn('[chatConversationHistory] Tool-result has invalid toolCallId format:', {
+        toolCallId,
+        toolName: rest.toolName,
+      });
+      // Skip this tool result if the ID doesn't match the pattern
+      return null;
+    }
+
     // Convert to v5's structured output format
     let output: { type: string; value: unknown };
     if (isError) {
@@ -166,18 +234,13 @@ function convertToolResultPart(part: unknown): unknown {
       }
     }
 
-    // Ensure toolCallId exists and is valid
-    // If it's missing or invalid, preserve the original part
-    if (!rest.toolCallId || typeof rest.toolCallId !== 'string') {
-      return part;
-    }
-
     return {
       ...rest,
       output,
     };
   }
 
+  // Already in v5 format or doesn't need conversion
   return part;
 }