diff --git a/build-linuxcnc-wasm-standalone-probe.sh b/build-linuxcnc-wasm-standalone-probe.sh
index 87a68e8..c20a0eb 100755
--- a/build-linuxcnc-wasm-standalone-probe.sh
+++ b/build-linuxcnc-wasm-standalone-probe.sh
@@ -85,6 +85,8 @@ case "$mode" in
         tooldata_mmap_backend_shim=$(./list-linuxcnc-wasm-safe-shims.sh tooldata_mmap_backend.cc)
         tooldata_runtime_stubs_shim=$(./list-linuxcnc-wasm-safe-shims.sh tooldata_runtime_stubs.cc)
         tooldata_common_source=$(LINUXCNC_ROOT="$linuxcnc_root" ./list-linuxcnc-source-files.sh src/emc/tooldata/tooldata_common.cc)
+        grep -F 'LinuxCNC source basis: src/emc/tooldata/tooldata_common.cc provides' core/wasm_shims/tooldata/tooldata_common_probe_main.cc >/dev/null
+        grep -F 'LinuxCNC source basis: src/emc/tooldata/tooldata_mmap.cc, tooldata_nml.cc,' core/wasm_shims/tooldata/tooldata_probe_main.cc >/dev/null
         sources+=(
             "$tooldata_common_source"
             "$tooldata_mmap_backend_shim"
diff --git a/core/wasm_shims/tooldata/tooldata_common_probe_main.cc b/core/wasm_shims/tooldata/tooldata_common_probe_main.cc
index eb4c30c..4b06605 100644
--- a/core/wasm_shims/tooldata/tooldata_common_probe_main.cc
+++ b/core/wasm_shims/tooldata/tooldata_common_probe_main.cc
@@ -7,6 +7,8 @@
 #include <vector>
 #include <unistd.h>
 
+// LinuxCNC source basis: src/emc/tooldata/tooldata_common.cc provides
+// tool table parsing, formatting, load/save, and DB mode entry points.
 namespace {
 
 std::string make_temp_template(const char *name) {
diff --git a/core/wasm_shims/tooldata/tooldata_probe_main.cc b/core/wasm_shims/tooldata/tooldata_probe_main.cc
index c86dfc1..77497e9 100644
--- a/core/wasm_shims/tooldata/tooldata_probe_main.cc
+++ b/core/wasm_shims/tooldata/tooldata_probe_main.cc
@@ -9,6 +9,8 @@
 #include <unistd.h>
 #include <vector>
 
+// LinuxCNC source basis: src/emc/tooldata/tooldata_mmap.cc, tooldata_nml.cc,
+// tooldata_db.cc, and taskclass.cc cover these tooldata runtime edge cases.
 namespace {
 
 std::string make_temp_path(const char *name) {