diff --git a/check-linuxcnc-wasm-shims-source-map.sh b/check-linuxcnc-wasm-shims-source-map.sh
index fd38b42..b1f54c3 100755
--- a/check-linuxcnc-wasm-shims-source-map.sh
+++ b/check-linuxcnc-wasm-shims-source-map.sh
@@ -102,6 +102,28 @@ grep -F 'retval = bp::exec(cmd, main_namespace, main_namespace);' \
     "$linuxcnc_root/src/emc/pythonplugin/python_plugin.cc" >/dev/null
 grep -F 'PyObject *rv = PyObject_Call(function.ptr(), tupleargs.ptr(), kwargs.ptr());' \
     "$linuxcnc_root/src/emc/pythonplugin/python_plugin.cc" >/dev/null
+grep -F 'PyErr_Fetch(&exc,&val,&tb);' \
+    "$linuxcnc_root/src/emc/rs274ngc/interp_python.cc" >/dev/null
+grep -F 'PyErr_NormalizeException(&exc,&val,&tb);' \
+    "$linuxcnc_root/src/emc/rs274ngc/interp_python.cc" >/dev/null
+grep -F 'if (Py_IsInitialized()) {' \
+    "$linuxcnc_root/src/emc/pythonplugin/python_plugin.cc" >/dev/null
+grep -F '#define callmethod(o, m, f, ...) PyObject_CallMethod((o), (char*)(m), (char*)(f), ## __VA_ARGS__)' \
+    "$linuxcnc_root/src/emc/rs274ngc/gcodemodule.cc" >/dev/null
+grep -F 'PyObject *result = PyObject_GetAttrString(callback, "parameter_file");' \
+    "$linuxcnc_root/src/emc/rs274ngc/gcodemodule.cc" >/dev/null
+grep -F 'PyErr_Format(PyExc_TypeError,' \
+    "$linuxcnc_root/src/emc/rs274ngc/gcodemodule.cc" >/dev/null
+grep -F 'return Py_BuildValue("[ddd][ddd][ddd][ddd]",' \
+    "$linuxcnc_root/src/emc/rs274ngc/gcodemodule.cc" >/dev/null
+grep -F 'PyObject *m = PyModule_Create(&gcode_moduledef);' \
+    "$linuxcnc_root/src/emc/rs274ngc/gcodemodule.cc" >/dev/null
+grep -F 'PyType_Ready(&LineCodeType);' \
+    "$linuxcnc_root/src/emc/rs274ngc/gcodemodule.cc" >/dev/null
+grep -F 'PyModule_AddObject(m, "linecode", (PyObject*)&LineCodeType);' \
+    "$linuxcnc_root/src/emc/rs274ngc/gcodemodule.cc" >/dev/null
+grep -F 'PyObject_SetAttrString(m, "MAX_ERROR", PyLong_FromLong(maxerror));' \
+    "$linuxcnc_root/src/emc/rs274ngc/gcodemodule.cc" >/dev/null
 grep -F '#define TOOL_MMAP_FILENAME ".tool.mmap"' "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
 grep -F 'int tool_nml_register(CANON_TOOL_TABLE *tblptr)' "$linuxcnc_root/src/emc/tooldata/tooldata_nml.cc" >/dev/null
 grep -F 'int tooldata_db_init(char progname_plus_args[]' "$linuxcnc_root/src/emc/tooldata/tooldata_db.cc" >/dev/null
@@ -313,11 +335,28 @@ for needle in [
     if needle not in python_plugin_probe:
         raise SystemExit(f"PythonPlugin probe missing disabled-python status assertion: {needle}")
 for needle in [
-    "Py_IsInitialized",
-    "PyObject_CallMethod",
-    "Py_BuildValue",
-    "PyModule_Create",
-    "PyType_Ready",
+    "static PyTypeObject none_type = {\"NoneType\"};",
+    "static PyObject none_object = {&none_type};",
+    "PyObject *_Py_NoneStructPtr = &none_object;",
+    "int Py_IsInitialized(void)",
+    "return 1;",
+    "PyObject *PyErr_Occurred(void)",
+    "return nullptr;",
+    "void PyErr_Fetch(PyObject **exc, PyObject **val, PyObject **tb)",
+    "*exc = nullptr;",
+    "*val = nullptr;",
+    "*tb = nullptr;",
+    "int PyCallable_Check(PyObject *)",
+    "return 0;",
+    "PyObject *PyObject_CallMethod(PyObject *, char *, char *, ...)",
+    "PyObject *PyObject_GetAttrString(PyObject *, const char *)",
+    "return &none_object;",
+    "PyObject *Py_BuildValue(const char *, ...)",
+    "PyObject *PyModule_Create(PyModuleDef *)",
+    "int PyModule_AddObject(PyObject *, const char *, PyObject *)",
+    "int PyType_Ready(PyTypeObject *)",
+    "void *PyObject_NewShim(std::size_t size, PyTypeObject *type)",
+    "std::calloc(1, size)",
 ]:
     if needle not in python_c_api_shim:
         raise SystemExit(f"Python C API shim missing symbol boundary: {needle}")
@@ -362,6 +401,8 @@ for phrase in [
     "`wordfree()` cleanup",
     "must not become a shell expansion feature",
     "must not become Python execution",
+    "Python C API shim must return inert objects",
+    "must not call into CPython runtime",
     "keeping Python execution disabled",
     "must not execute `bp::exec`, `bp::exec_file`, or",
     "inactive-DB return values",
diff --git a/docs/linuxcnc-wasm-shims-source-map.md b/docs/linuxcnc-wasm-shims-source-map.md
index bab4b27..0ad52e4 100644
--- a/docs/linuxcnc-wasm-shims-source-map.md
+++ b/docs/linuxcnc-wasm-shims-source-map.md
@@ -55,6 +55,10 @@ only; it must not add CNC behavior and must not expand the temporary smoke parse
 
 - `core/wasm_shims/python_c_api_shim.cc` satisfies Python C API symbols used by
   LinuxCNC RS274/remap sources; it must not become Python execution.
+- The Python C API shim must return inert objects, null exceptions, false
+  callable/type checks, and successful module/type registration statuses only
+  to satisfy LinuxCNC `interp_python.cc`, `gcodemodule.cc`, and
+  `python_plugin.cc` link expectations; it must not call into CPython runtime.
 - `core/wasm_shims/pythonplugin/python_plugin.cc` must preserve LinuxCNC
   `PythonPlugin` status edges for `PLUGIN_NO_SECTION`, `PLUGIN_BAD_INIFILE`,
   `PLUGIN_PYTHON_NOT_INITIALIZED`, `PLUGIN_NO_CALLABLE`, and