MCP Calculate Server

Instructions

Implementation Reference

• server.py:11-64 (handler)

  Core handler function decorated with @mcp.tool(). Evaluates math expressions using SymPy via eval with custom locals, dispatches to specialized handlers for complex cases (integrals, solves, matrices), formats results, catches errors.
  def calculate_expression(expression: str) -> str: """ calculate mathematical expressions using the `sympify` function from `sympy`, parse and compute the input mathematical expression string, supports direct calls to SymPy functions (automatically recognizes x, y, z as symbolic variables) Parameters: expression (str): Mathematical expression, e.g., "223 - 344 * 6" or "sin(pi/2) + log(10)".Replace special symbols with approximate values, e.g., pi → 3.1415" Example expressions: "2 + 3*5" # Basic arithmetic → 17 "expand((x + 1)**2)" # Expand → x² + 2x + 1 "diff(sin(x), x)" # Derivative → cos(x) "integrate(exp(x), (x, 0, 1))" # Definite integral → E - 1 "solve(x**2 - 4, x)" # Solve equation → [-2, 2] "limit(tan(x)/x, x, 0)" # Limit → 1 "Sum(k, (k, 1, 10)).doit()" # Summation → 55 "Matrix([[1, 2], [3, 4]]).inv()" # Matrix inverse → [[-2, 1], [3/2, -1/2]] "simplify((x**2 - 1)/(x + 1))" # Simplify → x - 1 "factor(x**2 - 2*x - 15)" # Factorize → (x - 5)(x + 3) "series(cos(x), x, 0, 4)" # Taylor series → 1 - x²/2 + x⁴/24 + O(x⁴) "integrate(exp(-x**2)*sin(x), (x, -oo, oo))" # Complex integral "solve([x**2 + y**2 - 1, x + y - 1], [x, y])" # Solve system of equations "Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]]).eigenvals()" # Matrix eigenvalues Returns: str: Calculation result. If the expression cannot be parsed or computed, returns an error message (str). """ try: # Define common symbolic variables x, y, z = sp.symbols('x y z') # Create local namespace containing all sympy functions and symbolic variables locals_dict = {**sp.__dict__, 'x': x, 'y': y, 'z': z} # Special handling for various types of expressions # 1. Handle complex integral expressions if "integrate" in expression and ("oo" in expression or "-oo" in expression): return handle_complex_integration(expression, locals_dict) # 2. Handle system of equations solving expressions elif "solve(" in expression and "[" in expression and "]" in expression: return handle_equation_solving(expression, locals_dict) # 3. Handle matrix eigenvalue calculation expressions elif "eigenvals" in expression or "eigenvects" in expression: return handle_matrix_eigenvalues(expression, locals_dict) # 4. General expression calculation else: # First try to evaluate the expression directly result = eval(expression, globals(), locals_dict) # Process based on result type return format_result(result) except Exception as e: return f"Error: {e}"
• server.py:10-10 (registration)

  The @mcp.tool() decorator registers the calculate_expression function as an MCP tool on the FastMCP server instance.
  @mcp.tool()
• server.py:11-33 (schema)

  Function signature with type hints (str -> str) and comprehensive docstring defining input/output schema, parameters, examples, and behavior for MCP tool schema generation.
  def calculate_expression(expression: str) -> str: """ calculate mathematical expressions using the `sympify` function from `sympy`, parse and compute the input mathematical expression string, supports direct calls to SymPy functions (automatically recognizes x, y, z as symbolic variables) Parameters: expression (str): Mathematical expression, e.g., "223 - 344 * 6" or "sin(pi/2) + log(10)".Replace special symbols with approximate values, e.g., pi → 3.1415" Example expressions: "2 + 3*5" # Basic arithmetic → 17 "expand((x + 1)**2)" # Expand → x² + 2x + 1 "diff(sin(x), x)" # Derivative → cos(x) "integrate(exp(x), (x, 0, 1))" # Definite integral → E - 1 "solve(x**2 - 4, x)" # Solve equation → [-2, 2] "limit(tan(x)/x, x, 0)" # Limit → 1 "Sum(k, (k, 1, 10)).doit()" # Summation → 55 "Matrix([[1, 2], [3, 4]]).inv()" # Matrix inverse → [[-2, 1], [3/2, -1/2]] "simplify((x**2 - 1)/(x + 1))" # Simplify → x - 1 "factor(x**2 - 2*x - 15)" # Factorize → (x - 5)(x + 3) "series(cos(x), x, 0, 4)" # Taylor series → 1 - x²/2 + x⁴/24 + O(x⁴) "integrate(exp(-x**2)*sin(x), (x, -oo, oo))" # Complex integral "solve([x**2 + y**2 - 1, x + y - 1], [x, y])" # Solve system of equations "Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]]).eigenvals()" # Matrix eigenvalues Returns: str: Calculation result. If the expression cannot be parsed or computed, returns an error message (str). """
• server.py:167-227 (helper)

  Key helper utility to format SymPy computation results (dicts for eigenvalues, lists for solutions, evalf for numerical, etc.) into readable strings.
  def format_result(result): """Format output based on result type""" try: # Handle dictionary type results (e.g., eigenvalues) if isinstance(result, dict): formatted = "{" for key, value in result.items(): # Try numerical computation try: key_eval = key.evalf() except: key_eval = key formatted += f"{key_eval}: {value}, " if formatted.endswith(", "): formatted = formatted[:-2] formatted += "}" return formatted # Handle list type results (e.g., solutions to equations) elif isinstance(result, list): formatted = "[" for item in result: # Check if it's a tuple (e.g., coordinate points) if isinstance(item, tuple): coords = [] for val in item: # Try numerical computation try: val_eval = val.evalf() coords.append(str(val_eval)) except: coords.append(str(val)) formatted += "(" + ", ".join(coords) + "), " else: # Try numerical computation try: item_eval = item.evalf() formatted += f"{item_eval}, " except: formatted += f"{item}, " if formatted.endswith(", "): formatted = formatted[:-2] formatted += "]" return formatted # Other types of results else: # Try numerical computation try: return str(result.evalf()) except: return str(result) except Exception as e: return f"Result formatting error: {e}, original result: {result}"