MCP Workspace Server

/** * write_file tool implementation * Provides file writing capabilities within the workspace */ import { ServerConfig } from '../config.js'; import { resolveSafePath } from '../utils/pathUtils.js'; import { writeFileAtomic } from '../utils/fsUtils.js'; import { createReadOnlyError, classifyError } from '../utils/errors.js'; /** * Input parameters for write_file tool */ export interface WriteFileInput { path: string; content: string; createDirectories?: boolean; } /** * Output from write_file tool */ export interface WriteFileOutput { path: string; bytesWritten: number; created: boolean; } /** * Tool metadata for MCP registration */ export const writeFileTool = { name: 'write_file', description: 'Create or overwrite a file in the workspace. Supports atomic writes and automatic parent directory creation.', inputSchema: { type: 'object', properties: { path: { type: 'string', description: 'Relative path to the file to write', }, content: { type: 'string', description: 'Content to write to the file', }, createDirectories: { type: 'boolean', description: 'Whether to create parent directories if they do not exist', default: false, }, }, required: ['path', 'content'], }, }; /** * Executes the write_file tool * @param input - Tool input parameters * @param config - Server configuration * @returns File path, bytes written, and creation status */ export async function executeWriteFile( input: WriteFileInput, config: ServerConfig ): Promise<WriteFileOutput> { const requestedPath = input.path; const content = input.content; const createDirectories = input.createDirectories ?? false; // Check read-only mode if (config.readOnly) { throw createReadOnlyError('Write'); } try { // Validate and resolve the path const resolvedPath = await resolveSafePath(config.workspaceRoot, requestedPath); // Write the file atomically const { bytesWritten, created } = await writeFileAtomic( resolvedPath, content, createDirectories ); return { path: requestedPath, bytesWritten, created, }; } catch (error: unknown) { // Classify and re-throw the error throw classifyError(error, 'write_file'); } }