health_check

Instructions

Implementation Reference

• src/build123d_mcp/tools/health_check.py:6-52 (handler)

  The core handler function that performs the health check. It tests PNG render (VTK), SVG render (HLR projection), STEP export, and STL export with a trivial Box shape, returning JSON with ok/error per capability.

  def health_check(_session) -> str:
      results: dict = {}
  
      # PNG render (VTK + display)
      try:
          from build123d import Box
          from build123d_mcp.tools.render import _QUALITY, _do_render_png
          img_bytes, _warnings = _do_render_png([("test", Box(1, 1, 1), None)], _QUALITY["standard"], "iso", "", None, 0.0, 0.0)
          results["render_png"] = {"ok": True, "bytes": len(img_bytes)}
      except Exception as e:
          results["render_png"] = {"ok": False, "error": str(e)}
  
      # SVG render (build123d HLR projection)
      try:
          from build123d import Box
          from build123d_mcp.tools.render import _do_render_svg
          svg = _do_render_svg([("test", Box(1, 1, 1), None)], "iso", "", None, 0.0, 0.0)
          results["render_svg"] = {"ok": True, "bytes": len(svg)}
      except Exception as e:
          results["render_svg"] = {"ok": False, "error": str(e)}
  
      # STEP export
      try:
          from build123d import Box, export_step
          fd, path = tempfile.mkstemp(suffix=".step")
          os.close(fd)
          export_step(Box(1, 1, 1), path)
          results["export_step"] = {"ok": True, "bytes": os.path.getsize(path)}
          os.unlink(path)
      except Exception as e:
          results["export_step"] = {"ok": False, "error": str(e)}
  
      # STL export
      try:
          from build123d import Box, Mesher
          fd, path = tempfile.mkstemp(suffix=".stl")
          os.close(fd)
          m = Mesher()
          m.add_shape(Box(1, 1, 1))
          m.write(path)
          results["export_stl"] = {"ok": True, "bytes": os.path.getsize(path)}
          os.unlink(path)
      except Exception as e:
          results["export_stl"] = {"ok": False, "error": str(e)}
  
      results["ok"] = all(v["ok"] for v in results.values() if isinstance(v, dict) and "ok" in v)
      return json.dumps(results, indent=2)

• src/build123d_mcp/server.py:123-126 (registration)

  MCP tool registration via @mcp.tool() decorator. The server-level health_check() delegates to _session.health_check().

  @mcp.tool()
  def health_check() -> str:
      """Verify that render and export dependencies are working. Tests PNG render (VTK), SVG render (build123d HLR), STEP export, and STL export with a trivial shape. Returns JSON with ok/error per capability. Run at session start if you suspect a missing dependency."""
      return _session.health_check()

• src/build123d_mcp/worker.py:121-123 (registration)

  Worker dispatch: routes the 'health_check' operation string to the health_check function from tools/health_check.py.

  if op == "health_check":
      from build123d_mcp.tools.health_check import health_check
      return health_check(session)

• src/build123d_mcp/worker.py:290-291 (registration)

  WorkerSession.health_check() method that sends a 'health_check' RPC call with RENDER_TIMEOUT.

  def health_check(self) -> str:
      return self._call("health_check", {}, self._RENDER_TIMEOUT)

• tests/test_tools.py:916-925 (helper)

  Test for health_check: verifies it returns valid JSON with all expected keys (ok, export_step, export_stl, render_svg) and that export checks pass.

  def test_health_check_returns_json(session):
      data = json.loads(health_check(session))
      assert "ok" in data
      assert "export_step" in data
      assert "export_stl" in data
      assert "render_svg" in data
      assert data["export_step"]["ok"] is True
      assert data["export_stl"]["ok"] is True
      assert data["render_svg"]["ok"] is True