Make the ReadManyFiles tool share the "DEFAULT_MAX_LINES_TEXT_FILE=2000" limit across files.

The current implementation can return 2000 x N lines when reading N files, such a length can be either extremely slow or infeasible for LLMs to process.

packages/core/src/tools/read-many-files.ts

@@ -21,6 +21,7 @@ import {
   processSingleFileContent,
   DEFAULT_ENCODING,
   getSpecificMimeType,
+  DEFAULT_MAX_LINES_TEXT_FILE,
 } from '../utils/fileUtils.js';
 import { PartListUnion } from '@google/genai';
 import { Config, DEFAULT_FILE_FILTERING_OPTIONS } from '../config/config.js';
@@ -360,6 +361,8 @@ ${finalExclusionPatternsForDescription
     }
 
     const sortedFiles = Array.from(filesToConsider).sort();
+    const file_line_limit =
+      DEFAULT_MAX_LINES_TEXT_FILE / Math.max(1, sortedFiles.length);
 
     const fileProcessingPromises = sortedFiles.map(
       async (filePath): Promise<FileProcessingResult> => {
@@ -398,6 +401,8 @@ ${finalExclusionPatternsForDescription
             filePath,
             this.config.getTargetDir(),
             this.config.getFileSystemService(),
+            0,
+            file_line_limit,
           );
 
           if (fileReadResult.error) {

packages/core/src/utils/fileUtils.ts

@@ -11,7 +11,7 @@ import mime from 'mime-types';
 import { FileSystemService } from '../services/fileSystemService.js';
 
 // Constants for text file processing
-const DEFAULT_MAX_LINES_TEXT_FILE = 2000;
+export const DEFAULT_MAX_LINES_TEXT_FILE = 2000;
 const MAX_LINE_LENGTH_TEXT_FILE = 2000;
 
 // Default values for encoding and separator format