MCP Smart Filesystem Server

Instructions

Implementation Reference

• index.ts:65-77 (registration)

  Registration of the 'list_directory' tool in the MCP tools array, specifying name, description, and input schema requiring a 'path' parameter.
  name: 'list_directory', description: 'List contents of a directory with metadata including file sizes and line counts', inputSchema: { type: 'object', properties: { path: { type: 'string', description: "Directory path to list. Use '.' for workspace root" } }, required: ['path'] } },
• index.ts:269-281 (handler)

  Dispatch handler in the CallToolRequestSchema that parses input arguments, validates the path, invokes the listDirectory function, and formats the response as MCP content.
  case 'list_directory': { const schema = z.object({ path: z.string() }); const { path } = schema.parse(args); const validatedPath = await validatePath(path); const result = await listDirectory(validatedPath); return { content: [{ type: 'text', text: JSON.stringify(result, null, 2) }] }; }
• lib.ts:176-192 (schema)

  TypeScript interfaces defining the structure of directory entries and the overall directory listing output returned by the listDirectory handler.
  export interface DirectoryEntry { name: string; type: 'file' | 'directory'; size: string | null; lines?: number; itemCount?: number; } export interface DirectoryListing { path: string; entries: DirectoryEntry[]; summary: { totalFiles: number; totalDirectories: number; totalSize: string; }; }
• lib.ts:194-267 (handler)

  Core implementation of the list_directory tool: asynchronously reads directory entries, categorizes files and directories, computes metadata (sizes, line counts for small text files, subdir item counts), and returns structured DirectoryListing.
  export async function listDirectory(dirPath: string): Promise<DirectoryListing> { const entries = await fs.readdir(dirPath, { withFileTypes: true }); const result: DirectoryEntry[] = []; let totalFiles = 0; let totalDirs = 0; let totalBytes = 0; for (const entry of entries) { const fullPath = path.join(dirPath, entry.name); if (entry.isDirectory()) { totalDirs++; try { const subEntries = await fs.readdir(fullPath); result.push({ name: entry.name, type: 'directory', size: null, itemCount: subEntries.length }); } catch { result.push({ name: entry.name, type: 'directory', size: null, itemCount: 0 }); } } else if (entry.isFile()) { totalFiles++; try { const stats = await fs.stat(fullPath); totalBytes += stats.size; // For text files, try to count lines let lines: number | undefined; if (stats.size < 10 * 1024 * 1024) { // Only for files < 10MB const isBinary = await isBinaryFile(fullPath); if (!isBinary) { try { const content = await readFileContent(fullPath); lines = countLines(content); } catch { // Ignore errors reading file content } } } result.push({ name: entry.name, type: 'file', size: formatSize(stats.size), lines }); } catch { result.push({ name: entry.name, type: 'file', size: '0 B' }); } } } return { path: dirPath, entries: result, summary: { totalFiles, totalDirectories: totalDirs, totalSize: formatSize(totalBytes) } }; }