feat(core): Save large tool outputs to a file and return truncated lines (#6240)

packages/core/src/tools/read-file.test.ts

@@ -38,6 +38,9 @@ describe('ReadFileTool', () => {
       getFileSystemService: () => new StandardFileSystemService(),
       getTargetDir: () => tempRootDir,
       getWorkspaceContext: () => createMockWorkspaceContext(tempRootDir),
+      storage: {
+        getProjectTempDir: () => path.join(tempRootDir, '.temp'),
+      },
     } as unknown as Config;
     tool = new ReadFileTool(mockConfigInstance);
   });
@@ -76,6 +79,24 @@ describe('ReadFileTool', () => {
       );
     });
 
+    it('should allow access to files in project temp directory', () => {
+      const tempDir = path.join(tempRootDir, '.temp');
+      const params: ReadFileToolParams = {
+        absolute_path: path.join(tempDir, 'temp-file.txt'),
+      };
+      const result = tool.build(params);
+      expect(typeof result).not.toBe('string');
+    });
+
+    it('should show temp directory in error message when path is outside workspace and temp dir', () => {
+      const params: ReadFileToolParams = {
+        absolute_path: '/completely/outside/path.txt',
+      };
+      expect(() => tool.build(params)).toThrow(
+        /File path must be within one of the workspace directories.*or within the project temp directory/,
+      );
+    });
+
     it('should throw error if path is empty', () => {
       const params: ReadFileToolParams = {
         absolute_path: '',
@@ -409,6 +430,24 @@ describe('ReadFileTool', () => {
       );
     });
 
+    it('should successfully read files from project temp directory', async () => {
+      const tempDir = path.join(tempRootDir, '.temp');
+      await fsp.mkdir(tempDir, { recursive: true });
+      const tempFilePath = path.join(tempDir, 'temp-output.txt');
+      const tempFileContent = 'This is temporary output content';
+      await fsp.writeFile(tempFilePath, tempFileContent, 'utf-8');
+
+      const params: ReadFileToolParams = { absolute_path: tempFilePath };
+      const invocation = tool.build(params) as ToolInvocation<
+        ReadFileToolParams,
+        ToolResult
+      >;
+
+      const result = await invocation.execute(abortSignal);
+      expect(result.llmContent).toBe(tempFileContent);
+      expect(result.returnDisplay).toBe('');
+    });
+
     describe('with .geminiignore', () => {
       beforeEach(async () => {
         await fsp.writeFile(

packages/core/src/tools/read-file.ts

@@ -180,9 +180,16 @@ export class ReadFileTool extends BaseDeclarativeTool<
     }
 
     const workspaceContext = this.config.getWorkspaceContext();
-    if (!workspaceContext.isPathWithinWorkspace(filePath)) {
+    const projectTempDir = this.config.storage.getProjectTempDir();
+    const resolvedFilePath = path.resolve(filePath);
+    const resolvedProjectTempDir = path.resolve(projectTempDir);
+    const isWithinTempDir =
+      resolvedFilePath.startsWith(resolvedProjectTempDir + path.sep) ||
+      resolvedFilePath === resolvedProjectTempDir;
+
+    if (!workspaceContext.isPathWithinWorkspace(filePath) && !isWithinTempDir) {
       const directories = workspaceContext.getDirectories();
-      return `File path must be within one of the workspace directories: ${directories.join(', ')}`;
+      return `File path must be within one of the workspace directories: ${directories.join(', ')} or within the project temp directory: ${projectTempDir}`;
     }
     if (params.offset !== undefined && params.offset < 0) {
       return 'Offset must be a non-negative number';