fix(core): resolve EISDIR errors during file processing (#21527) (#27041)

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

@@ -199,8 +199,8 @@ ${finalExclusionPatternsForDescription
           const fullPath = path.join(dir, normalizedP);
           let exists = false;
           try {
-            await fsPromises.access(fullPath);
-            exists = true;
+            const st = await fsPromises.stat(fullPath);
+            exists = st.isFile();
           } catch {
             exists = false;
           }

packages/core/src/utils/fileUtils.ts

@@ -15,6 +15,7 @@ import { ToolErrorType } from '../tools/tool-error.js';
 import { BINARY_EXTENSIONS } from './ignorePatterns.js';
 import { createRequire as createModuleRequire } from 'node:module';
 import { debugLogger } from './debugLogger.js';
+
 import {
   DEFAULT_MAX_LINES_TEXT_FILE,
   MAX_LINE_LENGTH_TEXT_FILE,
@@ -350,7 +351,9 @@ export async function isEmpty(filePath: string): Promise<boolean> {
  */
 export async function isBinaryFile(filePath: string): Promise<boolean> {
   try {
-    return await isBinaryFileCheck(filePath);
+    const stats = await fsPromises.stat(filePath);
+    if (!stats.isFile()) return false;
+    return await isBinaryFileCheck(filePath, stats.size);
   } catch (error) {
     debugLogger.warn(
       `Failed to check if file is binary: ${filePath}`,