diff --git a/app/api/proxy/route.ts b/app/api/proxy/route.ts
index 05704c7d5b..388d695cf9 100644
--- a/app/api/proxy/route.ts
+++ b/app/api/proxy/route.ts
@@ -16,13 +16,42 @@ export async function POST(request: Request) {
         throw new Error(`Tool not found: ${toolId}`)
       }
 
-      // Use executeTool with skipProxy=true to prevent recursive proxy calls
-      const result = await executeTool(toolId, params, true)
+      // Use executeTool with skipProxy=true to prevent recursive proxy calls, and skipPostProcess=true to prevent duplicate post-processing
+      const result = await executeTool(toolId, params, true, true)
 
       if (!result.success) {
-        throw new Error(
-          tool.transformError ? tool.transformError(result) : 'Tool returned an error'
-        )
+        if (tool.transformError) {
+          try {
+            const errorResult = tool.transformError(result)
+
+            // Handle both string and Promise return types
+            if (typeof errorResult === 'string') {
+              throw new Error(errorResult)
+            } else {
+              // It's a Promise, await it
+              const transformedError = await errorResult
+              // If it's a string or has an error property, use it
+              if (typeof transformedError === 'string') {
+                throw new Error(transformedError)
+              } else if (
+                transformedError &&
+                typeof transformedError === 'object' &&
+                'error' in transformedError
+              ) {
+                throw new Error(transformedError.error || 'Tool returned an error')
+              }
+              // Fallback
+              throw new Error('Tool returned an error')
+            }
+          } catch (e) {
+            if (e instanceof Error) {
+              throw e
+            }
+            throw new Error('Tool returned an error')
+          }
+        } else {
+          throw new Error('Tool returned an error')
+        }
       }
 
       return NextResponse.json(result)
diff --git a/executor/types.ts b/executor/types.ts
index 3cfcc9f936..1e40f1970b 100644
--- a/executor/types.ts
+++ b/executor/types.ts
@@ -164,7 +164,13 @@ export interface Tool<P = any, O = Record<string, any>> {
     error?: string
   }>
 
-  transformError?: (error: any) => string // Function to format error messages
+  transformError?: (error: any) =>
+    | string
+    | Promise<{
+        success: boolean
+        output: O
+        error?: string
+      }> // Function to format error messages
 }
 
 /**
diff --git a/tools/docs/create.ts b/tools/docs/create.ts
index 1c9b0c76e1..6402faf4b0 100644
--- a/tools/docs/create.ts
+++ b/tools/docs/create.ts
@@ -50,6 +50,44 @@ export const createTool: ToolConfig<GoogleDocsToolParams, GoogleDocsCreateRespon
       return requestBody
     },
   },
+  postProcess: async (result, params, executeTool) => {
+    // Only add content if it was provided and not already added during creation
+    // The Google Docs API doesn't directly support content in the create request,
+    // so we need to add it separately via the write tool
+    if (result.success && params.content) {
+      console.log('Google Docs create - Post-processing: Adding content to document')
+      const documentId = result.output.metadata.documentId
+
+      if (documentId) {
+        try {
+          const writeParams = {
+            accessToken: params.accessToken,
+            documentId: documentId,
+            content: params.content,
+          }
+          console.log('Content to add:', params.content)
+
+          // Use the write tool to add content
+          const writeResult = await executeTool('google_docs_write', writeParams)
+
+          if (!writeResult.success) {
+            console.warn(
+              'Failed to add content to document, but document was created:',
+              writeResult.error
+            )
+          } else {
+            console.log('Google Docs create - Content added successfully')
+          }
+        } catch (error) {
+          console.warn('Error adding content to document:', error)
+          // Don't fail the overall operation if adding content fails
+        }
+      }
+    }
+
+    // Return the original result regardless of post-processing outcome
+    return result
+  },
   transformResponse: async (response: Response) => {
     if (!response.ok) {
       let errorText = ''
@@ -67,7 +105,9 @@ export const createTool: ToolConfig<GoogleDocsToolParams, GoogleDocsCreateRespon
     try {
       // Get the response data
       const responseText = await response.text()
+
       const data = JSON.parse(responseText)
+
       const documentId = data.documentId
       const title = data.title
 
@@ -86,19 +126,27 @@ export const createTool: ToolConfig<GoogleDocsToolParams, GoogleDocsCreateRespon
         },
       }
     } catch (error) {
+      console.error('Google Docs create - Error processing response:', error)
       throw error
     }
   },
-  transformError: (error) => {
-    if (typeof error === 'object' && error !== null) {
-      if (error.message) {
-        return error.message
-      }
-      return (
-        JSON.stringify(error, null, 2) || 'An error occurred while creating Google Docs document'
-      )
-    }
+  transformError: async (error) => {
+    console.error('Google Docs create - Transform error:', error)
 
-    return error.toString() || 'An error occurred while creating Google Docs document'
+    const errorMessage =
+      typeof error === 'object' && error !== null
+        ? error.message || JSON.stringify(error, null, 2)
+        : error.toString() || 'An error occurred while creating Google Docs document'
+
+    return {
+      success: false,
+      output: {
+        metadata: {
+          documentId: '',
+          title: '',
+        },
+      },
+      error: errorMessage,
+    }
   },
 }
diff --git a/tools/docs/read.ts b/tools/docs/read.ts
index 521eafca53..2912bf28ab 100644
--- a/tools/docs/read.ts
+++ b/tools/docs/read.ts
@@ -70,11 +70,23 @@ export const readTool: ToolConfig<GoogleDocsToolParams, GoogleDocsReadResponse>
       },
     }
   },
-  transformError: (error) => {
-    if (typeof error === 'object' && error !== null) {
-      return JSON.stringify(error) || 'An error occurred while reading from Google Docs'
+  transformError: async (error) => {
+    const errorMessage =
+      typeof error === 'object' && error !== null
+        ? error.message || JSON.stringify(error, null, 2)
+        : error.toString() || 'An error occurred while reading Google Docs document'
+
+    return {
+      success: false,
+      output: {
+        content: '',
+        metadata: {
+          documentId: '',
+          title: '',
+        },
+      },
+      error: errorMessage,
     }
-    return error.message || 'An error occurred while reading from Google Docs'
   },
 }
 
diff --git a/tools/docs/write.ts b/tools/docs/write.ts
index 6900e0dae0..852634f5a7 100644
--- a/tools/docs/write.ts
+++ b/tools/docs/write.ts
@@ -48,14 +48,13 @@ export const writeTool: ToolConfig<GoogleDocsToolParams, GoogleDocsWriteResponse
       }
 
       // Following the exact format from the Google Docs API examples
-      // Note: We're not including tabId since it's optional for the main document body
+      // Always insert at the end of the document to avoid duplication
+      // See: https://developers.google.com/docs/api/reference/rest/v1/documents/request#InsertTextRequest
       const requestBody = {
         requests: [
           {
             insertText: {
-              location: {
-                index: 1,
-              },
+              endOfSegmentLocation: {},
               text: params.content,
             },
           },
@@ -117,14 +116,22 @@ export const writeTool: ToolConfig<GoogleDocsToolParams, GoogleDocsWriteResponse
       throw error
     }
   },
-  transformError: (error) => {
-    if (typeof error === 'object' && error !== null) {
-      if (error.message) {
-        return error.message
-      }
-      return JSON.stringify(error, null, 2) || 'An error occurred while writing to Google Docs'
-    }
+  transformError: async (error) => {
+    const errorMessage =
+      typeof error === 'object' && error !== null
+        ? error.message || JSON.stringify(error, null, 2)
+        : error.toString() || 'An error occurred while writing to Google Docs'
 
-    return error.toString() || 'An error occurred while writing to Google Docs'
+    return {
+      success: false,
+      output: {
+        updatedContent: false,
+        metadata: {
+          documentId: '',
+          title: '',
+        },
+      },
+      error: errorMessage,
+    }
   },
 }
diff --git a/tools/index.ts b/tools/index.ts
index 8d375bf40f..2761a43e35 100644
--- a/tools/index.ts
+++ b/tools/index.ts
@@ -279,7 +279,7 @@ function getCustomTool(customToolId: string): ToolConfig | undefined {
         error: undefined,
       }
     },
-    transformError: (error: any) =>
+    transformError: async (error: any) =>
       `Custom tool execution error: ${error.message || 'Unknown error'}`,
   }
 }
@@ -288,7 +288,8 @@ function getCustomTool(customToolId: string): ToolConfig | undefined {
 export async function executeTool(
   toolId: string,
   params: Record<string, any>,
-  skipProxy = false
+  skipProxy = false,
+  skipPostProcess = false
 ): Promise<ToolResponse> {
   try {
     const tool = getTool(toolId)
@@ -313,11 +314,36 @@ export async function executeTool(
     // For internal routes or when skipProxy is true, call the API directly
     if (tool.request.isInternalRoute || skipProxy) {
       const result = await handleInternalRequest(toolId, tool, params)
+
+      // Apply post-processing if available and not skipped
+      if (tool.postProcess && result.success && !skipPostProcess) {
+        try {
+          return await tool.postProcess(result, params, executeTool)
+        } catch (error) {
+          console.error(`Error in post-processing for tool ${toolId}:`, error)
+          // Return original result if post-processing fails
+          return result
+        }
+      }
+
       return result
     }
 
     // For external APIs, use the proxy
-    return await handleProxyRequest(toolId, params)
+    const result = await handleProxyRequest(toolId, params)
+
+    // Apply post-processing if available and not skipped
+    if (tool.postProcess && result.success && !skipPostProcess) {
+      try {
+        return await tool.postProcess(result, params, executeTool)
+      } catch (error) {
+        console.error(`Error in post-processing for tool ${toolId}:`, error)
+        // Return original result if post-processing fails
+        return result
+      }
+    }
+
+    return result
   } catch (error: any) {
     console.error(`Error executing tool ${toolId}:`, error)
 
@@ -396,12 +422,58 @@ async function handleInternalRequest(
       error: undefined,
     }
   } catch (error: any) {
+    console.error(`Error executing internal tool ${toolId}:`, error)
+
     // Use the tool's error transformer if available
     if (tool.transformError) {
-      return {
-        success: false,
-        output: {},
-        error: tool.transformError(error),
+      try {
+        const errorResult = tool.transformError(error)
+
+        // Handle both string and Promise return types
+        if (typeof errorResult === 'string') {
+          return {
+            success: false,
+            output: {},
+            error: errorResult,
+          }
+        } else {
+          // It's a Promise, await it
+          const transformedError = await errorResult
+          // If it's a string or has an error property, use it
+          if (typeof transformedError === 'string') {
+            return {
+              success: false,
+              output: {},
+              error: transformedError,
+            }
+          } else if (transformedError && typeof transformedError === 'object') {
+            // If it's already a ToolResponse, return it directly
+            if ('success' in transformedError) {
+              return transformedError
+            }
+            // If it has an error property, use it
+            if ('error' in transformedError) {
+              return {
+                success: false,
+                output: {},
+                error: transformedError.error,
+              }
+            }
+          }
+          // Fallback
+          return {
+            success: false,
+            output: {},
+            error: 'Unknown error',
+          }
+        }
+      } catch (transformError) {
+        console.error(`Error transforming error for tool ${toolId}:`, transformError)
+        return {
+          success: false,
+          output: {},
+          error: error.message || 'Unknown error',
+        }
       }
     }
 
diff --git a/tools/types.ts b/tools/types.ts
index b12f753d72..fdbb145541 100644
--- a/tools/types.ts
+++ b/tools/types.ts
@@ -14,7 +14,7 @@ export interface OAuthConfig {
   additionalScopes?: string[] // Additional scopes required for the tool
 }
 
-export interface ToolConfig<P = any, R extends ToolResponse = ToolResponse> {
+export interface ToolConfig<P = any, R = any> {
   // Basic tool identification
   id: string
   name: string
@@ -48,9 +48,16 @@ export interface ToolConfig<P = any, R extends ToolResponse = ToolResponse> {
   // Direct execution in browser (optional) - bypasses HTTP request
   directExecution?: (params: P) => Promise<R | undefined>
 
+  // Post-processing (optional) - allows additional processing after the initial request
+  postProcess?: (
+    result: R extends ToolResponse ? R : ToolResponse,
+    params: P,
+    executeTool: (toolId: string, params: Record<string, any>) => Promise<ToolResponse>
+  ) => Promise<R extends ToolResponse ? R : ToolResponse>
+
   // Response handling
-  transformResponse: (response: Response) => Promise<R>
-  transformError: (error: any) => string
+  transformResponse?: (response: Response) => Promise<R>
+  transformError?: (error: any) => string | Promise<R>
 }
 
 export interface TableRow {
diff --git a/tools/utils.ts b/tools/utils.ts
index 209402b473..2547ff9ccd 100644
--- a/tools/utils.ts
+++ b/tools/utils.ts
@@ -77,12 +77,40 @@ export async function executeRequest(
       }
 
       // Use the tool's error transformer or a default message
-      const error = tool.transformError
-        ? tool.transformError(errorContent)
-        : errorContent.message || `${toolId} API error: ${externalResponse.statusText}`
+      if (tool.transformError) {
+        try {
+          const errorResult = tool.transformError(errorContent)
 
-      console.error(`${toolId} error:`, error)
-      throw new Error(error)
+          // Handle both string and Promise return types
+          if (typeof errorResult === 'string') {
+            throw new Error(errorResult)
+          } else {
+            // It's a Promise, await it
+            const transformedError = await errorResult
+            // If it's a string or has an error property, use it
+            if (typeof transformedError === 'string') {
+              throw new Error(transformedError)
+            } else if (
+              transformedError &&
+              typeof transformedError === 'object' &&
+              'error' in transformedError
+            ) {
+              throw new Error(transformedError.error || 'Tool returned an error')
+            }
+            // Fallback
+            throw new Error('Tool returned an error')
+          }
+        } catch (e) {
+          if (e instanceof Error) {
+            throw e
+          }
+          throw new Error(`${toolId} API error: ${externalResponse.statusText}`)
+        }
+      } else {
+        const error = errorContent.message || `${toolId} API error: ${externalResponse.statusText}`
+        console.error(`${toolId} error:`, error)
+        throw new Error(error)
+      }
     }
 
     const transformResponse =