OpenVSP MCP Server

Instructions

Implementation Reference

• src/openvsp_mcp/tool.py:39-46 (handler)

  Handler function for the 'openvsp.run_vspaero' tool, decorated with @app.tool for MCP registration. Delegates to core execute_openvsp with VSPAero enabled.

  @app.tool(
      name="openvsp.run_vspaero",
      description=(
          "Run OpenVSP edits followed by VSPAero. Provide geometry commands and case_name."),
      meta={"version": "0.1.0", "categories": ["geometry", "aero"]},
  )
  def run_vspaero(request: OpenVSPRequest) -> OpenVSPResponse:
      return execute_openvsp(request.model_copy(update={"run_vspaero": True}))

• src/openvsp_mcp/models.py:18-25 (schema)

  Pydantic schema for tool input: OpenVSPRequest, including run_vspaero flag specific to this tool's purpose.

  class OpenVSPRequest(BaseModel):
      """Parameters controlling geometry edits and optional VSPAero run."""
  
      geometry_file: str = Field(..., description="Path to the .vsp3 file")
      set_commands: list[VSPCommand] = Field(default_factory=list, description="Commands to run")
      run_vspaero: bool = Field(True, description="Execute VSPAero after editing geometry")
      case_name: str = Field("case", description="Base name for generated results")

• src/openvsp_mcp/core.py:29-70 (helper)

  Core helper implementing OpenVSP script execution and conditional VSPAero run, invoked by the tool handler.

  def execute_openvsp(request: OpenVSPRequest) -> OpenVSPResponse:
      """Run OpenVSP (and optionally VSPAero) using the provided request."""
  
      with tempfile.TemporaryDirectory(prefix="openvsp_mcp_") as tmpdir:
          workdir = Path(tmpdir)
          script_path = _write_script(request, workdir)
  
          try:
              result = subprocess.run(
                  [OPENVSP_BIN, "-script", str(script_path)],
                  check=False,
                  capture_output=True,
              )
          except FileNotFoundError as exc:  # pragma: no cover
              raise RuntimeError("OpenVSP binary not found") from exc
  
          if result.returncode not in _OK_EXIT_CODES:
              message = result.stderr.decode("utf-8", errors="ignore").strip()
              if not message:
                  message = result.stdout.decode("utf-8", errors="ignore").strip() or "OpenVSP script execution failed"
              raise RuntimeError(message)
  
          vspaero_output: str | None = None
          if request.run_vspaero:
              try:
                  aero = subprocess.run(
                      [VSPAERO_BIN, request.geometry_file, request.case_name],
                      check=False,
                      capture_output=True,
                  )
              except FileNotFoundError as exc:  # pragma: no cover
                  raise RuntimeError("VSPAero binary not found") from exc
  
              if aero.returncode != 0:
                  message = aero.stderr.decode("utf-8", errors="ignore").strip()
                  if not message:
                      message = aero.stdout.decode("utf-8", errors="ignore").strip() or "VSPAero execution failed"
                  raise RuntimeError(message)
              vspaero_output = str(Path(request.case_name).with_suffix(".adb"))
  
          return OpenVSPResponse(script_path=str(script_path), result_path=vspaero_output)

• src/openvsp_mcp/core.py:79-103 (helper)

  Generates the temporary OpenVSP script (.vspscript) from the request's set_commands and geometry_file.

  def _write_script(request: OpenVSPRequest, working_dir: Path) -> Path:
      script_path = working_dir / "automation.vspscript"
      commands: Iterable[VSPCommand] = request.set_commands or []
  
      script_lines = [
          "// Auto-generated by openvsp-mcp",
          "void main() {",
          "    ClearVSPModel();",
          f"    ReadVSPFile(\"{request.geometry_file}\");",
      ]
  
      for command in commands:
          script_lines.append(f"    {_ensure_statement(command.command)}")
  
      script_lines.extend(
          [
              "    Update();",
              f"    SetVSP3FileName(\"{request.geometry_file}\");",
              f"    WriteVSPFile(\"{request.geometry_file}\", SET_ALL);",
              "}",
          ]
      )
  
      script_path.write_text("\n".join(script_lines) + "\n", encoding="utf-8")
      return script_path

• src/openvsp_mcp/__main__.py:73-74 (registration)

  Entry point registers tools by calling build_tool on the FastMCP app instance, which defines openvsp.run_vspaero.

  app = FastMCP(SERVICE_NAME, SERVICE_DESCRIPTION)
  build_tool(app)