diff --git a/check-linuxcnc-wasm-shims-source-map.sh b/check-linuxcnc-wasm-shims-source-map.sh
index dfdacc1..88f86ec 100755
--- a/check-linuxcnc-wasm-shims-source-map.sh
+++ b/check-linuxcnc-wasm-shims-source-map.sh
@@ -33,6 +33,7 @@ grep -F 'print_rcs_error_new' "$linuxcnc_root/src/libnml/rcs/rcs_print.cc" >/dev
 grep -F 'rtapi_snprintf' "$linuxcnc_root/src/rtapi/uspace_common.h" >/dev/null
 grep -F 'class PythonPlugin' "$linuxcnc_root/src/emc/pythonplugin/python_plugin.hh" >/dev/null
 grep -F 'PythonPlugin::instantiate' "$linuxcnc_root/src/emc/pythonplugin/python_plugin.cc" >/dev/null
+grep -F 'if (status < PLUGIN_OK)' "$linuxcnc_root/src/emc/pythonplugin/python_plugin.cc" >/dev/null
 grep -F '#define TOOL_MMAP_FILENAME ".tool.mmap"' "$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
@@ -118,6 +119,7 @@ for phrase in [
     "RS274/WASM manifest",
     "browser-safe LinuxCNC adaptations",
     "inactive-DB return values",
+    "negative-status short-circuit behavior",
 ]:
     if phrase not in source_map:
         raise SystemExit(f"docs/linuxcnc-wasm-shims-source-map.md missing boundary phrase: {phrase}")
diff --git a/core/wasm_shims/pythonplugin/python_plugin.cc b/core/wasm_shims/pythonplugin/python_plugin.cc
index 2100e2e..65c559c 100644
--- a/core/wasm_shims/pythonplugin/python_plugin.cc
+++ b/core/wasm_shims/pythonplugin/python_plugin.cc
@@ -58,6 +58,9 @@ int PythonPlugin::call(const char *,
     if (!callable) {
         return PLUGIN_NO_CALLABLE;
     }
+    if (status < PLUGIN_OK) {
+        return status;
+    }
 
     retval = boost::python::object();
     exception_msg = handle_pyerror();
@@ -72,6 +75,11 @@ int PythonPlugin::run_string(const char *, boost::python::object &retval, bool)
 }
 
 int PythonPlugin::call_method(boost::python::object, boost::python::object &retval) {
+    // LinuxCNC source basis: src/emc/pythonplugin/python_plugin.cc returns the
+    // existing negative plugin status before invoking a Python callable.
+    if (status < PLUGIN_OK) {
+        return status;
+    }
     retval = boost::python::object();
     status = PLUGIN_OK;
     return status;
diff --git a/core/wasm_shims/pythonplugin/python_plugin_probe_main.cc b/core/wasm_shims/pythonplugin/python_plugin_probe_main.cc
index bf04a28..72fb00c 100644
--- a/core/wasm_shims/pythonplugin/python_plugin_probe_main.cc
+++ b/core/wasm_shims/pythonplugin/python_plugin_probe_main.cc
@@ -17,6 +17,12 @@ int main() {
         return 7;
     }
     boost::python::object retval;
+    if (plugin->call(nullptr, "noop", boost::python::object(), boost::python::object(), retval) != PLUGIN_BAD_INIFILE) {
+        return 14;
+    }
+    if (plugin->call_method(boost::python::object(), retval) != PLUGIN_BAD_INIFILE) {
+        return 15;
+    }
     if (plugin->run_string("noop", retval, false) != PLUGIN_OK) {
         return 3;
     }
diff --git a/docs/linuxcnc-wasm-shims-source-map.md b/docs/linuxcnc-wasm-shims-source-map.md
index d7fbcb4..81c2aa3 100644
--- a/docs/linuxcnc-wasm-shims-source-map.md
+++ b/docs/linuxcnc-wasm-shims-source-map.md
@@ -24,7 +24,7 @@ only; it must not add CNC behavior and must not expand the temporary smoke parse
 | `core/wasm_shims/rtapi_compat.cc` | `src/rtapi/uspace_common.h`, `src/rtapi/rtapi.h` | Provides userspace RTAPI formatting declarations used by RS274/NML code. |
 | `core/wasm_shims/tooldata/tooldata_mmap_backend.cc` | `src/emc/tooldata/tooldata_mmap.cc` | Replaces native mmap storage with an in-memory WASM-safe backend for probes. |
 | `core/wasm_shims/tooldata/tooldata_runtime_stubs.cc` | `src/emc/tooldata/tooldata_nml.cc`, `src/emc/tooldata/tooldata_db.cc` | Satisfies NML and external tool database entry points without native services, preserving inactive-DB return values. |
-| `core/wasm_shims/pythonplugin/python_plugin.cc` | `src/emc/pythonplugin/python_plugin.cc`, `src/emc/pythonplugin/python_plugin.hh` | Keeps LinuxCNC PythonPlugin API available while Python execution is disabled for browser-safe probes. |
+| `core/wasm_shims/pythonplugin/python_plugin.cc` | `src/emc/pythonplugin/python_plugin.cc`, `src/emc/pythonplugin/python_plugin.hh` | Keeps LinuxCNC PythonPlugin API and negative-status short-circuit behavior available while Python execution is disabled for browser-safe probes. |
 
 ## Boundaries