Desmos MCP Server

Instructions

Implementation Reference

• src/main.py:198-198 (registration)

  Registers the 'plot_multiple_functions' tool using the @mcp.tool() decorator.

  @mcp.tool()

• src/main.py:199-246 (handler)

  The main handler function that plots multiple mathematical functions on a single graph using SymPy's plotting capabilities. It processes each formula, appends series to a plot, saves to desktop, encodes as base64 data URI, and returns the image.

  async def plot_multiple_functions(
      ctx: MCPContext,
      formulas: List[str],
      x_range: Optional[List[float]] = [-10, 10],
      y_range: Optional[List[float]] = None,
  ) -> str:
      """Plots multiple functions on the same graph."""
      try:
          await ctx.progress.start(total=len(formulas) + 1, message="Starting multi-plot...")
          x = sympy.symbols('x')
          p = sympy.plot(show=False)
          
          for i, formula in enumerate(formulas):
              await ctx.progress.report(i + 1, message=f"Processing formula {i+1}: {formula}")
              expr = sympy.sympify(formula)
              line_label = formula
              line_color = f"C{i}"
              series = sympy.plot(expr, (x, x_range[0], x_range[1]), show=False, line_color=line_color, label=line_label)[0]
              p.append(series)
  
          if x_range:
              p.xlim = x_range
          if y_range:
              p.ylim = y_range
          
          p.legend = True
  
          # Save the plot to a file
          desktop_path = os.path.join(os.path.expanduser('~'), 'Desktop')
          save_dir = os.path.join(desktop_path, 'Desmos-MCP')
          os.makedirs(save_dir, exist_ok=True)
          timestamp = datetime.now().strftime("%Y%m%d%H%M%S")
          filename = f"multi_plot_{timestamp}.png"
          p.save(os.path.join(save_dir, filename))
  
          await ctx.progress.report(len(formulas) + 1, message="Encoding image...")
          buf = io.BytesIO()
          p.save(buf)
          buf.seek(0)
          img_base64 = base64.b64encode(buf.read()).decode('utf-8')
          data_uri = f"data:image/png;base64,{img_base64}"
          
          await ctx.progress.end()
          return f"Successfully plotted {len(formulas)} functions. Image: {data_uri}"
  
      except Exception as e:
          await ctx.progress.end()
          return f"Error plotting multiple functions. Details: {e}"