diff --git a/packages/core/src/tools/read-file.test.ts b/packages/core/src/tools/read-file.test.ts
index 82958184..7f7f5ede 100644
--- a/packages/core/src/tools/read-file.test.ts
+++ b/packages/core/src/tools/read-file.test.ts
@@ -219,7 +219,7 @@ describe('ReadFileTool', () => {
         returnDisplay: 'Path is a directory.',
         error: {
           message: `Path is a directory, not a file: ${dirPath}`,
-          type: ToolErrorType.INVALID_TOOL_PARAMS,
+          type: ToolErrorType.TARGET_IS_DIRECTORY,
         },
       });
     });
diff --git a/packages/core/src/tools/read-file.ts b/packages/core/src/tools/read-file.ts
index da8a004d..7e9e8535 100644
--- a/packages/core/src/tools/read-file.ts
+++ b/packages/core/src/tools/read-file.ts
@@ -14,7 +14,7 @@ import {
   ToolLocation,
   ToolResult,
 } from './tools.js';
-import { ToolErrorType } from './tool-error.js';
+
 import { PartUnion } from '@google/genai';
 import {
   processSingleFileContent,
@@ -79,44 +79,12 @@ class ReadFileToolInvocation extends BaseToolInvocation<
     );
 
     if (result.error) {
-      // Map error messages to ToolErrorType
-      let errorType: ToolErrorType;
-      let llmContent: string;
-
-      // Check error message patterns to determine error type
-      if (
-        result.error.includes('File not found') ||
-        result.error.includes('does not exist') ||
-        result.error.includes('ENOENT')
-      ) {
-        errorType = ToolErrorType.FILE_NOT_FOUND;
-        llmContent =
-          'Could not read file because no file was found at the specified path.';
-      } else if (
-        result.error.includes('is a directory') ||
-        result.error.includes('EISDIR')
-      ) {
-        errorType = ToolErrorType.INVALID_TOOL_PARAMS;
-        llmContent =
-          'Could not read file because the provided path is a directory, not a file.';
-      } else if (
-        result.error.includes('too large') ||
-        result.error.includes('File size exceeds')
-      ) {
-        errorType = ToolErrorType.FILE_TOO_LARGE;
-        llmContent = `Could not read file. ${result.error}`;
-      } else {
-        // Other read errors map to READ_CONTENT_FAILURE
-        errorType = ToolErrorType.READ_CONTENT_FAILURE;
-        llmContent = `Could not read file. ${result.error}`;
-      }
-
       return {
-        llmContent,
+        llmContent: result.llmContent,
         returnDisplay: result.returnDisplay || 'Error reading file',
         error: {
           message: result.error,
-          type: errorType,
+          type: result.errorType,
         },
       };
     }
diff --git a/packages/core/src/tools/read-many-files.ts b/packages/core/src/tools/read-many-files.ts
index 52529ce9..b3568cad 100644
--- a/packages/core/src/tools/read-many-files.ts
+++ b/packages/core/src/tools/read-many-files.ts
@@ -21,6 +21,7 @@ import {
   processSingleFileContent,
   DEFAULT_ENCODING,
   getSpecificMimeType,
+  ProcessedFileReadResult,
 } from '../utils/fileUtils.js';
 import { PartListUnion } from '@google/genai';
 import { Config, DEFAULT_FILE_FILTERING_OPTIONS } from '../config/config.js';
@@ -84,9 +85,7 @@ type FileProcessingResult =
       success: true;
       filePath: string;
       relativePathForDisplay: string;
-      fileReadResult: NonNullable<
-        Awaited<ReturnType<typeof processSingleFileContent>>
-      >;
+      fileReadResult: ProcessedFileReadResult;
       reason?: undefined;
     }
   | {
diff --git a/packages/core/src/utils/fileUtils.ts b/packages/core/src/utils/fileUtils.ts
index 8dfdbc22..f0b491ed 100644
--- a/packages/core/src/utils/fileUtils.ts
+++ b/packages/core/src/utils/fileUtils.ts
@@ -9,6 +9,7 @@ import path from 'node:path';
 import { PartUnion } from '@google/genai';
 import mime from 'mime-types';
 import { FileSystemService } from '../services/fileSystemService.js';
+import { ToolErrorType } from '../tools/tool-error.js';
 
 // Constants for text file processing
 const DEFAULT_MAX_LINES_TEXT_FILE = 2000;
@@ -196,18 +197,11 @@ export async function detectFileType(
   return 'text';
 }
 
-export enum FileErrorType {
-  FILE_NOT_FOUND = 'FILE_NOT_FOUND',
-  IS_DIRECTORY = 'IS_DIRECTORY',
-  FILE_TOO_LARGE = 'FILE_TOO_LARGE',
-  READ_ERROR = 'READ_ERROR',
-}
-
 export interface ProcessedFileReadResult {
   llmContent: PartUnion; // string for text, Part for image/pdf/unreadable binary
   returnDisplay: string;
   error?: string; // Optional error message for the LLM if file processing failed
-  errorType?: FileErrorType; // Structured error type using enum
+  errorType?: ToolErrorType; // Structured error type
   isTruncated?: boolean; // For text files, indicates if content was truncated
   originalLineCount?: number; // For text files
   linesShown?: [number, number]; // For text files [startLine, endLine] (1-based for display)
@@ -232,33 +226,32 @@ export async function processSingleFileContent(
     if (!fs.existsSync(filePath)) {
       // Sync check is acceptable before async read
       return {
-        llmContent: '',
+        llmContent:
+          'Could not read file because no file was found at the specified path.',
         returnDisplay: 'File not found.',
         error: `File not found: ${filePath}`,
-        errorType: FileErrorType.FILE_NOT_FOUND,
+        errorType: ToolErrorType.FILE_NOT_FOUND,
       };
     }
     const stats = await fs.promises.stat(filePath);
     if (stats.isDirectory()) {
       return {
-        llmContent: '',
+        llmContent:
+          'Could not read file because the provided path is a directory, not a file.',
         returnDisplay: 'Path is a directory.',
         error: `Path is a directory, not a file: ${filePath}`,
-        errorType: FileErrorType.IS_DIRECTORY,
+        errorType: ToolErrorType.TARGET_IS_DIRECTORY,
       };
     }
 
-    const fileSizeInBytes = stats.size;
-    // 20MB limit
-    const maxFileSize = 20 * 1024 * 1024;
-
-    if (fileSizeInBytes > maxFileSize) {
-      throw new Error(
-        `File size exceeds the 20MB limit: ${filePath} (${(
-          fileSizeInBytes /
-          (1024 * 1024)
-        ).toFixed(2)}MB)`,
-      );
+    const fileSizeInMB = stats.size / (1024 * 1024);
+    if (fileSizeInMB > 20) {
+      return {
+        llmContent: 'File size exceeds the 20MB limit.',
+        returnDisplay: 'File size exceeds the 20MB limit.',
+        error: `File size exceeds the 20MB limit: ${filePath} (${fileSizeInMB.toFixed(2)}MB)`,
+        errorType: ToolErrorType.FILE_TOO_LARGE,
+      };
     }
 
     const fileType = await detectFileType(filePath);
@@ -373,6 +366,7 @@ export async function processSingleFileContent(
       llmContent: `Error reading file ${displayPath}: ${errorMessage}`,
       returnDisplay: `Error reading file ${displayPath}: ${errorMessage}`,
       error: `Error reading file ${filePath}: ${errorMessage}`,
+      errorType: ToolErrorType.READ_CONTENT_FAILURE,
     };
   }
 }