applescript-mcp

Instructions

Implementation Reference

• src/categories/system.ts:15-30 (handler)

  Specific handler and schema for the 'volume' script in system category. Generates AppleScript 'set volume X' where X is level/100 *7 rounded. Tool name becomes 'system_volume' via prefixing.
  { name: "volume", description: "Set system volume", schema: { type: "object", properties: { level: { type: "number", minimum: 0, maximum: 100, }, }, required: ["level"], }, script: (args) => `set volume ${Math.round((args.level / 100) * 7)}`, },
• src/framework.ts:221-232 (registration)

  Registers the tool by dynamically generating the tools list for MCP, constructing 'system_volume' name from category 'system' + script 'volume'.
  this.server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: this.categories.flatMap((category) => category.scripts.map((script) => ({ name: `${category.name}_${script.name}`, // Changed from dot to underscore description: `[${category.description}] ${script.description}`, inputSchema: script.schema || { type: "object", properties: {}, }, })), ), }));
• src/framework.ts:234-281 (handler)

  Main handler for tool calls in MCP. Parses 'system_volume' by splitting on '_', finds system category and volume script, generates script content, and executes it.
  // Handle tool execution this.server.setRequestHandler(CallToolRequestSchema, async (request) => { const toolName = request.params.name; this.log("info", "Tool execution requested", { tool: toolName, hasArguments: !!request.params.arguments }); try { // Split on underscore instead of dot const [categoryName, ...scriptNameParts] = toolName.split("_"); const scriptName = scriptNameParts.join("_"); // Rejoin in case script name has underscores const category = this.categories.find((c) => c.name === categoryName); if (!category) { this.log("warning", "Category not found", { categoryName }); throw new McpError( ErrorCode.MethodNotFound, `Category not found: ${categoryName}`, ); } const script = category.scripts.find((s) => s.name === scriptName); if (!script) { this.log("warning", "Script not found", { categoryName, scriptName }); throw new McpError( ErrorCode.MethodNotFound, `Script not found: ${scriptName}`, ); } this.log("debug", "Generating script content", { categoryName, scriptName, isFunction: typeof script.script === "function" }); const scriptContent = typeof script.script === "function" ? script.script(request.params.arguments) : script.script; const result = await this.executeScript(scriptContent);
• src/framework.ts:176-214 (helper)

  Helper function that executes the generated AppleScript using 'osascript' command, returning the stdout result.
  private async executeScript(script: string): Promise<string> { // Log script execution (truncate long scripts for readability) const scriptPreview = script.length > 100 ? script.substring(0, 100) + "..." : script; this.log("debug", "Executing AppleScript", { scriptPreview }); try { const startTime = Date.now(); const { stdout } = await execAsync( `osascript -e '${script.replace(/'/g, "'\"'\"'")}'`, ); const executionTime = Date.now() - startTime; this.log("debug", "AppleScript executed successfully", { executionTimeMs: executionTime, outputLength: stdout.length }); return stdout.trim(); } catch (error) { // Properly type check the error object let errorMessage = "Unknown error occurred"; if (error && typeof error === "object") { if ("message" in error && typeof error.message === "string") { errorMessage = error.message; } else if (error instanceof Error) { errorMessage = error.message; } } else if (typeof error === "string") { errorMessage = error; } this.log("error", "AppleScript execution failed", { error: errorMessage, scriptPreview }); throw new Error(`AppleScript execution failed: ${errorMessage}`); } }