read-file.test.ts

/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
import { ReadFileTool, type ReadFileToolParams } from './read-file.js';
import { ToolErrorType } from './tool-error.js';
import path from 'node:path';
import { isSubpath } from '../utils/paths.js';
import os from 'node:os';
import fs from 'node:fs';
import fsp from 'node:fs/promises';
import type { Config } from '../config/config.js';
import { FileDiscoveryService } from '../services/fileDiscoveryService.js';
import { StandardFileSystemService } from '../services/fileSystemService.js';
import { createMockWorkspaceContext } from '../test-utils/mockWorkspaceContext.js';
import { WorkspaceContext } from '../utils/workspaceContext.js';
import { createMockMessageBus } from '../test-utils/mock-message-bus.js';
import { GEMINI_IGNORE_FILE_NAME } from '../config/constants.js';

vi.mock('../telemetry/loggers.js', () => ({
  logFileOperation: vi.fn(),
}));

vi.mock('./jit-context.js', () => ({
  discoverJitContext: vi.fn().mockResolvedValue(''),
  appendJitContext: vi.fn().mockImplementation((content, context) => {
    if (!context) return content;
    return `${content}\n\n--- Newly Discovered Project Context ---\n${context}\n--- End Project Context ---`;
  }),
  appendJitContextToParts: vi.fn().mockImplementation((content, context) => {
    const jitPart = {
      text: `\n\n--- Newly Discovered Project Context ---\n${context}\n--- End Project Context ---`,
    };
    const existing = Array.isArray(content) ? content : [content];
    return [...existing, jitPart];
  }),
  JIT_CONTEXT_PREFIX: '\n\n--- Newly Discovered Project Context ---\n',
  JIT_CONTEXT_SUFFIX: '\n--- End Project Context ---',
}));

describe('ReadFileTool', () => {
  let tempRootDir: string;
  let tool: ReadFileTool;
  const abortSignal = new AbortController().signal;

  beforeEach(async () => {
    // Create a unique temporary root directory for each test run
    const realTmp = await fsp.realpath(os.tmpdir());
    tempRootDir = await fsp.mkdtemp(path.join(realTmp, 'read-file-tool-root-'));

    const mockConfigInstance = {
      getFileService: () => new FileDiscoveryService(tempRootDir),
      getFileSystemService: () => new StandardFileSystemService(),
      getTargetDir: () => tempRootDir,
      getWorkspaceContext: () => createMockWorkspaceContext(tempRootDir),
      getFileFilteringOptions: () => ({
        respectGitIgnore: true,
        respectGeminiIgnore: true,
      }),
      storage: {
        getProjectTempDir: () => path.join(tempRootDir, '.temp'),
      },
      isInteractive: () => false,
      isPathAllowed(this: Config, absolutePath: string): boolean {
        const workspaceContext = this.getWorkspaceContext();
        if (workspaceContext.isPathWithinWorkspace(absolutePath)) {
          return true;
        }

        const projectTempDir = this.storage.getProjectTempDir();
        return isSubpath(path.resolve(projectTempDir), absolutePath);
      },
      validatePathAccess(this: Config, absolutePath: string): string | null {
        if (this.isPathAllowed(absolutePath)) {
          return null;
        }

        const workspaceDirs = this.getWorkspaceContext().getDirectories();
        const projectTempDir = this.storage.getProjectTempDir();
        return `Path not in workspace: Attempted path "${absolutePath}" resolves outside the allowed workspace directories: ${workspaceDirs.join(', ')} or the project temp directory: ${projectTempDir}`;
      },
    } as unknown as Config;
    tool = new ReadFileTool(mockConfigInstance, createMockMessageBus());
  });

  afterEach(async () => {
    // Clean up the temporary root directory
    if (fs.existsSync(tempRootDir)) {
      await fsp.rm(tempRootDir, { recursive: true, force: true });
    }
  });

  describe('build', () => {
    it('should return an invocation for valid params (absolute path within root)', () => {
      const params: ReadFileToolParams = {
        file_path: path.join(tempRootDir, 'test.txt'),
      };
      const result = tool.build(params);
      expect(typeof result).not.toBe('string');
    });

    it('should return an invocation for valid params (relative path within root)', () => {
      const params: ReadFileToolParams = {
        file_path: 'test.txt',
      };
      const result = tool.build(params);
      expect(typeof result).not.toBe('string');
      const invocation = result;
      expect(invocation.toolLocations()[0].path).toBe(
        path.join(tempRootDir, 'test.txt'),
      );
    });

    it('should throw error if path is outside root', () => {
      const params: ReadFileToolParams = {
        file_path: '/outside/root.txt',
      };
      expect(() => tool.build(params)).toThrow(/Path not in workspace/);
    });

    it('should allow access to files in project temp directory', () => {
      const tempDir = path.join(tempRootDir, '.temp');
      const params: ReadFileToolParams = {
        file_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 = {
        file_path: '/completely/outside/path.txt',
      };
      expect(() => tool.build(params)).toThrow(/Path not in workspace/);
    });

    it('should throw error if path is empty', () => {
      const params: ReadFileToolParams = {
        file_path: '',
      };
      expect(() => tool.build(params)).toThrow(
        /The 'file_path' parameter must be non-empty./,
      );
    });

    it('should throw error if start_line is less than 1', () => {
      const params: ReadFileToolParams = {
        file_path: path.join(tempRootDir, 'test.txt'),
        start_line: 0,
      };
      expect(() => tool.build(params)).toThrow('start_line must be at least 1');
    });

    it('should throw error if end_line is less than 1', () => {
      const params: ReadFileToolParams = {
        file_path: path.join(tempRootDir, 'test.txt'),
        end_line: 0,
      };
      expect(() => tool.build(params)).toThrow('end_line must be at least 1');
    });

    it('should throw error if start_line is greater than end_line', () => {
      const params: ReadFileToolParams = {
        file_path: path.join(tempRootDir, 'test.txt'),
        start_line: 10,
        end_line: 5,
      };
      expect(() => tool.build(params)).toThrow(
        'start_line cannot be greater than end_line',
      );
    });
  });

  describe('getDescription', () => {
    it('should return relative path without ranges', () => {
      const subDir = path.join(tempRootDir, 'sub', 'dir');
      const params: ReadFileToolParams = {
        file_path: path.join(subDir, 'file.txt'),
      };
      const invocation = tool.build(params);
      expect(typeof invocation).not.toBe('string');
      expect(invocation.getDescription()).toBe(
        path.join('sub', 'dir', 'file.txt'),
      );
    });

    it('should return shortened path when file path is deep', () => {
      const deepPath = path.join(
        tempRootDir,
        'very',
        'deep',
        'directory',
        'structure',
        'that',
        'exceeds',
        'the',
        'normal',
        'limit',
        'file.txt',
      );
      const params: ReadFileToolParams = { file_path: deepPath };
      const invocation = tool.build(params);
      expect(typeof invocation).not.toBe('string');
      const desc = invocation.getDescription();
      expect(desc).toContain('...');
      expect(desc).toContain('file.txt');
    });

    it('should handle non-normalized file paths correctly', () => {
      const subDir = path.join(tempRootDir, 'sub', 'dir');
      const params: ReadFileToolParams = {
        file_path: path.join(subDir, '..', 'dir', 'file.txt'),
      };
      const invocation = tool.build(params);
      expect(typeof invocation).not.toBe('string');
      expect(invocation.getDescription()).toBe(
        path.join('sub', 'dir', 'file.txt'),
      );
    });

    it('should return . if path is the root directory', () => {
      const params: ReadFileToolParams = { file_path: tempRootDir };
      const invocation = tool.build(params);
      expect(typeof invocation).not.toBe('string');
      expect(invocation.getDescription()).toBe('.');
    });
  });

  describe('execute', () => {
    it('should successfully read a file with a relative path', async () => {
      const filePath = path.join(tempRootDir, 'textfile.txt');
      const fileContent = 'This is a test file.';
      await fsp.writeFile(filePath, fileContent, 'utf-8');
      const params: ReadFileToolParams = { file_path: 'textfile.txt' };
      const invocation = tool.build(params);

      expect(await invocation.execute(abortSignal)).toEqual({
        llmContent: fileContent,
        returnDisplay: '',
      });
    });

    it('should return error if file does not exist', async () => {
      const filePath = path.join(tempRootDir, 'nonexistent.txt');
      const params: ReadFileToolParams = { file_path: filePath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result).toEqual({
        llmContent:
          'Could not read file because no file was found at the specified path.',
        returnDisplay: 'File not found.',
        error: {
          message: `File not found: ${filePath}`,
          type: ToolErrorType.FILE_NOT_FOUND,
        },
      });
    });

    it('should return success result for a text file', async () => {
      const filePath = path.join(tempRootDir, 'textfile.txt');
      const fileContent = 'This is a test file.';
      await fsp.writeFile(filePath, fileContent, 'utf-8');
      const params: ReadFileToolParams = { file_path: filePath };
      const invocation = tool.build(params);

      expect(await invocation.execute(abortSignal)).toEqual({
        llmContent: fileContent,
        returnDisplay: '',
      });
    });

    it('should return error if path is a directory', async () => {
      const dirPath = path.join(tempRootDir, 'directory');
      await fsp.mkdir(dirPath);
      const params: ReadFileToolParams = { file_path: dirPath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result).toEqual({
        llmContent:
          'Could not read file because the provided path is a directory, not a file.',
        returnDisplay: 'Path is a directory.',
        error: {
          message: `Path is a directory, not a file: ${dirPath}`,
          type: ToolErrorType.TARGET_IS_DIRECTORY,
        },
      });
    });

    it('should return error for a file that is too large', async () => {
      const filePath = path.join(tempRootDir, 'largefile.txt');
      // 21MB of content exceeds 20MB limit
      const largeContent = 'x'.repeat(21 * 1024 * 1024);
      await fsp.writeFile(filePath, largeContent, 'utf-8');
      const params: ReadFileToolParams = { file_path: filePath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result).toHaveProperty('error');
      expect(result.error?.type).toBe(ToolErrorType.FILE_TOO_LARGE);
      expect(result.error?.message).toContain(
        'File size exceeds the 20MB limit',
      );
    });

    it('should handle text file with lines exceeding maximum length', async () => {
      const filePath = path.join(tempRootDir, 'longlines.txt');
      const longLine = 'a'.repeat(2500); // Exceeds MAX_LINE_LENGTH_TEXT_FILE (2000)
      const fileContent = `Short line\n${longLine}\nAnother short line`;
      await fsp.writeFile(filePath, fileContent, 'utf-8');
      const params: ReadFileToolParams = { file_path: filePath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toContain(
        'IMPORTANT: The file content has been truncated',
      );
      expect(result.llmContent).toContain('--- FILE CONTENT (truncated) ---');
      expect(result.returnDisplay).toContain('some lines were shortened');
    });

    it('should handle image file and return appropriate content', async () => {
      const imagePath = path.join(tempRootDir, 'image.png');
      // Minimal PNG header
      const pngHeader = Buffer.from([
        0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a,
      ]);
      await fsp.writeFile(imagePath, pngHeader);
      const params: ReadFileToolParams = { file_path: imagePath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toEqual({
        inlineData: {
          data: pngHeader.toString('base64'),
          mimeType: 'image/png',
        },
      });
      expect(result.returnDisplay).toBe('Read image file: image.png');
    });

    it('should handle PDF file and return appropriate content', async () => {
      const pdfPath = path.join(tempRootDir, 'document.pdf');
      // Minimal PDF header
      const pdfHeader = Buffer.from('%PDF-1.4');
      await fsp.writeFile(pdfPath, pdfHeader);
      const params: ReadFileToolParams = { file_path: pdfPath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toEqual({
        inlineData: {
          data: pdfHeader.toString('base64'),
          mimeType: 'application/pdf',
        },
      });
      expect(result.returnDisplay).toBe('Read pdf file: document.pdf');
    });

    it('should handle binary file and skip content', async () => {
      const binPath = path.join(tempRootDir, 'binary.bin');
      // Binary data with null bytes
      const binaryData = Buffer.from([0x00, 0xff, 0x00, 0xff]);
      await fsp.writeFile(binPath, binaryData);
      const params: ReadFileToolParams = { file_path: binPath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toBe(
        'Cannot display content of binary file: binary.bin',
      );
      expect(result.returnDisplay).toBe('Skipped binary file: binary.bin');
    });

    it('should handle SVG file as text', async () => {
      const svgPath = path.join(tempRootDir, 'image.svg');
      const svgContent = '<svg><circle cx="50" cy="50" r="40"/></svg>';
      await fsp.writeFile(svgPath, svgContent, 'utf-8');
      const params: ReadFileToolParams = { file_path: svgPath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toBe(svgContent);
      expect(result.returnDisplay).toBe('Read SVG as text: image.svg');
    });

    it('should handle large SVG file', async () => {
      const svgPath = path.join(tempRootDir, 'large.svg');
      // Create SVG content larger than 1MB
      const largeContent = '<svg>' + 'x'.repeat(1024 * 1024 + 1) + '</svg>';
      await fsp.writeFile(svgPath, largeContent, 'utf-8');
      const params: ReadFileToolParams = { file_path: svgPath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toBe(
        'Cannot display content of SVG file larger than 1MB: large.svg',
      );
      expect(result.returnDisplay).toBe(
        'Skipped large SVG file (>1MB): large.svg',
      );
    });

    it('should handle empty file', async () => {
      const emptyPath = path.join(tempRootDir, 'empty.txt');
      await fsp.writeFile(emptyPath, '', 'utf-8');
      const params: ReadFileToolParams = { file_path: emptyPath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toBe('');
      expect(result.returnDisplay).toBe('');
    });

    it('should support start_line and end_line for text files', async () => {
      const filePath = path.join(tempRootDir, 'paginated.txt');
      const lines = Array.from({ length: 20 }, (_, i) => `Line ${i + 1}`);
      const fileContent = lines.join('\n');
      await fsp.writeFile(filePath, fileContent, 'utf-8');

      const params: ReadFileToolParams = {
        file_path: filePath,
        start_line: 6,
        end_line: 8,
      };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toContain(
        'IMPORTANT: The file content has been truncated',
      );
      expect(result.llmContent).toContain(
        'Status: Showing lines 6-8 of 20 total lines',
      );
      expect(result.llmContent).toContain('Line 6');
      expect(result.llmContent).toContain('Line 7');
      expect(result.llmContent).toContain('Line 8');
      expect(result.returnDisplay).toBe(
        'Read lines 6-8 of 20 from paginated.txt',
      );
    });

    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 = { file_path: tempFilePath };
      const invocation = tool.build(params);

      const result = await invocation.execute(abortSignal);
      expect(result.llmContent).toBe(tempFileContent);
      expect(result.returnDisplay).toBe('');
    });

    describe('with .geminiignore', () => {
      beforeEach(async () => {
        await fsp.writeFile(
          path.join(tempRootDir, GEMINI_IGNORE_FILE_NAME),
          ['foo.*', 'ignored/'].join('\n'),
        );
        const mockConfigInstance = {
          getFileService: () => new FileDiscoveryService(tempRootDir),
          getFileSystemService: () => new StandardFileSystemService(),
          getTargetDir: () => tempRootDir,
          getWorkspaceContext: () => new WorkspaceContext(tempRootDir),
          getFileFilteringOptions: () => ({
            respectGitIgnore: true,
            respectGeminiIgnore: true,
          }),
          storage: {
            getProjectTempDir: () => path.join(tempRootDir, '.temp'),
          },
          isPathAllowed(this: Config, absolutePath: string): boolean {
            const workspaceContext = this.getWorkspaceContext();
            if (workspaceContext.isPathWithinWorkspace(absolutePath)) {
              return true;
            }

            const projectTempDir = this.storage.getProjectTempDir();
            return isSubpath(path.resolve(projectTempDir), absolutePath);
          },
          validatePathAccess(
            this: Config,
            absolutePath: string,
          ): string | null {
            if (this.isPathAllowed(absolutePath)) {
              return null;
            }

            const workspaceDirs = this.getWorkspaceContext().getDirectories();
            const projectTempDir = this.storage.getProjectTempDir();
            return `Path not in workspace: Attempted path "${absolutePath}" resolves outside the allowed workspace directories: ${workspaceDirs.join(', ')} or the project temp directory: ${projectTempDir}`;
          },
        } as unknown as Config;
        tool = new ReadFileTool(mockConfigInstance, createMockMessageBus());
      });

      it('should throw error if path is ignored by a .geminiignore pattern', async () => {
        const ignoredFilePath = path.join(tempRootDir, 'foo.bar');
        await fsp.writeFile(ignoredFilePath, 'content', 'utf-8');
        const params: ReadFileToolParams = {
          file_path: ignoredFilePath,
        };
        const expectedError = `File path '${ignoredFilePath}' is ignored by configured ignore patterns.`;
        expect(() => tool.build(params)).toThrow(expectedError);
      });

      it('should throw error if file is in an ignored directory', async () => {
        const ignoredDirPath = path.join(tempRootDir, 'ignored');
        await fsp.mkdir(ignoredDirPath, { recursive: true });
        const ignoredFilePath = path.join(ignoredDirPath, 'file.txt');
        await fsp.writeFile(ignoredFilePath, 'content', 'utf-8');
        const params: ReadFileToolParams = {
          file_path: ignoredFilePath,
        };
        const expectedError = `File path '${ignoredFilePath}' is ignored by configured ignore patterns.`;
        expect(() => tool.build(params)).toThrow(expectedError);
      });

      it('should allow reading non-ignored files', async () => {
        const allowedFilePath = path.join(tempRootDir, 'allowed.txt');
        await fsp.writeFile(allowedFilePath, 'content', 'utf-8');
        const params: ReadFileToolParams = {
          file_path: allowedFilePath,
        };
        const invocation = tool.build(params);
        expect(typeof invocation).not.toBe('string');
      });

      it('should allow reading ignored files if respectGeminiIgnore is false', async () => {
        const ignoredFilePath = path.join(tempRootDir, 'foo.bar');
        await fsp.writeFile(ignoredFilePath, 'content', 'utf-8');

        const configNoIgnore = {
          getFileService: () => new FileDiscoveryService(tempRootDir),
          getFileSystemService: () => new StandardFileSystemService(),
          getTargetDir: () => tempRootDir,
          getWorkspaceContext: () => new WorkspaceContext(tempRootDir),
          getFileFilteringOptions: () => ({
            respectGitIgnore: true,
            respectGeminiIgnore: false,
          }),
          storage: {
            getProjectTempDir: () => path.join(tempRootDir, '.temp'),
          },
          isInteractive: () => false,
          isPathAllowed(this: Config, absolutePath: string): boolean {
            const workspaceContext = this.getWorkspaceContext();
            if (workspaceContext.isPathWithinWorkspace(absolutePath)) {
              return true;
            }

            const projectTempDir = this.storage.getProjectTempDir();
            return isSubpath(path.resolve(projectTempDir), absolutePath);
          },
          validatePathAccess(
            this: Config,
            absolutePath: string,
          ): string | null {
            if (this.isPathAllowed(absolutePath)) {
              return null;
            }

            const workspaceDirs = this.getWorkspaceContext().getDirectories();
            const projectTempDir = this.storage.getProjectTempDir();
            return `Path not in workspace: Attempted path "${absolutePath}" resolves outside the allowed workspace directories: ${workspaceDirs.join(', ')} or the project temp directory: ${projectTempDir}`;
          },
        } as unknown as Config;

        const toolNoIgnore = new ReadFileTool(
          configNoIgnore,
          createMockMessageBus(),
        );
        const params: ReadFileToolParams = {
          file_path: ignoredFilePath,
        };
        const invocation = toolNoIgnore.build(params);
        expect(typeof invocation).not.toBe('string');
      });
    });
  });

  describe('getSchema', () => {
    it('should return the base schema when no modelId is provided', () => {
      const schema = tool.getSchema();
      expect(schema.name).toBe(ReadFileTool.Name);
      expect(schema.description).toMatchSnapshot();
      expect(
        (schema.parametersJsonSchema as { properties: Record<string, unknown> })
          .properties,
      ).not.toHaveProperty('offset');
    });

    it('should return the schema from the resolver when modelId is provided', () => {
      const modelId = 'gemini-2.0-flash';
      const schema = tool.getSchema(modelId);
      expect(schema.name).toBe(ReadFileTool.Name);
      expect(schema.description).toMatchSnapshot();
    });

    it('should return the Gemini 3 schema when a Gemini 3 modelId is provided', () => {
      const modelId = 'gemini-3-pro-preview';
      const schema = tool.getSchema(modelId);
      expect(schema.name).toBe(ReadFileTool.Name);
      expect(schema.description).toMatchSnapshot();
      expect(schema.description).toContain('surgical reads');
    });
  });

  describe('JIT context discovery', () => {
    it('should append JIT context to output when enabled and context is found', async () => {
      const { discoverJitContext } = await import('./jit-context.js');
      vi.mocked(discoverJitContext).mockResolvedValue('Use the useAuth hook.');

      const filePath = path.join(tempRootDir, 'jit-test.txt');
      const fileContent = 'JIT test content.';
      await fsp.writeFile(filePath, fileContent, 'utf-8');

      const invocation = tool.build({ file_path: filePath });
      const result = await invocation.execute(abortSignal);

      expect(discoverJitContext).toHaveBeenCalled();
      expect(result.llmContent).toContain('Newly Discovered Project Context');
      expect(result.llmContent).toContain('Use the useAuth hook.');
    });

    it('should not append JIT context when disabled', async () => {
      const { discoverJitContext } = await import('./jit-context.js');
      vi.mocked(discoverJitContext).mockResolvedValue('');

      const filePath = path.join(tempRootDir, 'jit-disabled-test.txt');
      const fileContent = 'No JIT content.';
      await fsp.writeFile(filePath, fileContent, 'utf-8');

      const invocation = tool.build({ file_path: filePath });
      const result = await invocation.execute(abortSignal);

      expect(result.llmContent).not.toContain(
        'Newly Discovered Project Context',
      );
    });

    it('should append JIT context as Part array for non-string llmContent (binary files)', async () => {
      const { discoverJitContext } = await import('./jit-context.js');
      vi.mocked(discoverJitContext).mockResolvedValue(
        'Auth rules: use httpOnly cookies.',
      );

      // Create a minimal valid PNG file (1x1 pixel)
      const pngHeader = Buffer.from([
        0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
        0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01,
        0x08, 0x02, 0x00, 0x00, 0x00, 0x90, 0x77, 0x53, 0xde, 0x00, 0x00, 0x00,
        0x0c, 0x49, 0x44, 0x41, 0x54, 0x08, 0xd7, 0x63, 0xf8, 0xcf, 0xc0, 0x00,
        0x00, 0x00, 0x02, 0x00, 0x01, 0xe2, 0x21, 0xbc, 0x33, 0x00, 0x00, 0x00,
        0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82,
      ]);
      const filePath = path.join(tempRootDir, 'test-image.png');
      await fsp.writeFile(filePath, pngHeader);

      const invocation = tool.build({ file_path: filePath });
      const result = await invocation.execute(abortSignal);

      expect(discoverJitContext).toHaveBeenCalled();
      // Result should be an array containing both the image part and JIT context
      expect(Array.isArray(result.llmContent)).toBe(true);
      const parts = result.llmContent as Array<Record<string, unknown>>;
      const jitTextPart = parts.find(
        (p) =>
          // eslint-disable-next-line no-restricted-syntax
          typeof p['text'] === 'string' && p['text'].includes('Auth rules'),
      );
      expect(jitTextPart).toBeDefined();
      expect(jitTextPart!['text']).toContain(
        'Newly Discovered Project Context',
      );
      expect(jitTextPart!['text']).toContain(
        'Auth rules: use httpOnly cookies.',
      );
    });
  });
});