PureScript MCP Server

Instructions

Implementation Reference

• index.js:813-821 (handler)

  The core handler function for the 'getFunctionNames' tool. Parses PureScript code using Tree-sitter parser, executes a Tree-sitter query to capture function names, extracts the names from capture nodes, and returns them as a JSON array.
  "getFunctionNames": async (args) => { if (!treeSitterInitialized) throw new Error("Tree-sitter not initialized."); const code = await getCodeFromInput(args, false); const tree = purescriptTsParser.parse(code); const query = new Query(PureScriptLanguage, `(function name: (variable) @func.name)`); const captures = query.captures(tree.rootNode); const functionNames = captures.map(capture => capture.node.text); return { content: [{ type: "text", text: JSON.stringify(functionNames, null, 2) }] }; },
• index.js:616-623 (schema)

  The input schema definition for the 'getFunctionNames' tool, specifying that it requires a 'code' parameter of type string.
  name: "getFunctionNames", description: "Extract only function names from PureScript code snippets. Focuses specifically on functions, ignoring data types and classes. Quick analysis for code understanding.", inputSchema: { type: "object", properties: { code: { type: "string", description: "PureScript code snippet." } }, required: ["code"], additionalProperties: false }
• index.js:1158-1163 (registration)

  Registration via the tools/list MCP method, which returns the TOOL_DEFINITIONS array containing the schema for 'getFunctionNames'.
  if (method === 'tools/list') { const toolsToExclude = ['query_purescript_ast', 'query_purs_ide']; // Keep query_purs_ide for now, for direct access if needed const filteredToolDefinitions = TOOL_DEFINITIONS.filter( tool => !toolsToExclude.includes(tool.name) ); return createSuccessResponse(id, { tools: filteredToolDefinitions });
• index.js:1166-1179 (registration)

  The tools/call MCP request handler that dispatches to the specific tool handler by looking up in INTERNAL_TOOL_HANDLERS map.
  if (method === 'tools/call') { if (!params || typeof params.name !== 'string') { return createErrorResponse(id, -32602, "Invalid params: 'name' of tool is required for tools/call."); } const toolName = params.name; const toolArgs = params.arguments || {}; const handler = INTERNAL_TOOL_HANDLERS[toolName]; if (!handler) { return createErrorResponse(id, -32601, `Method not found (tool): ${toolName}`); } const result = await handler(toolArgs); // This now returns { content: [...] } return createSuccessResponse(id, result); // The entire { content: [...] } is the result for tools/call
• index.js:125-151 (helper)

  Helper function called by the handler to obtain the code from arguments. For getFunctionNames (snippet-oriented), it validates and returns args.code.
  // Helper to get code from input args (filePath or code string) async function getCodeFromInput(args, isModuleOriented = true) { if (isModuleOriented) { const hasFilePath = args && typeof args.filePath === 'string'; const hasCode = args && typeof args.code === 'string'; if ((hasFilePath && hasCode) || (!hasFilePath && !hasCode)) { throw new Error("Invalid input: Exactly one of 'filePath' or 'code' must be provided for module-oriented tools."); } if (hasFilePath) { if (!path.isAbsolute(args.filePath)) { throw new Error(`Invalid filePath: '${args.filePath}' is not an absolute path. Only absolute paths are supported.`); } try { return await fs.readFile(args.filePath, 'utf-8'); } catch (e) { throw new Error(`Failed to read file at ${args.filePath}: ${e.message}`); } } return args.code; } else { // Snippet-oriented if (!args || typeof args.code !== 'string') { throw new Error("Invalid input: 'code' (string) is required for snippet-oriented tools."); } return args.code; } }