diff --git a/core/wasm_shims/tooldata/tooldata.hh b/core/wasm_shims/tooldata/tooldata.hh
index d27bad8..1aae5b3 100644
--- a/core/wasm_shims/tooldata/tooldata.hh
+++ b/core/wasm_shims/tooldata/tooldata.hh
@@ -3,6 +3,8 @@
 #include "nml_intf/canon.hh"
 #include "nml_intf/emc_nml.hh"
 
+// LinuxCNC source basis: src/emc/tooldata/tooldata.hh declares the tooldata
+// API used by taskclass.cc, emccanon.cc, and RS274 tool table paths.
 extern "C" {
 
 typedef enum {
diff --git a/core/wasm_shims/tooldata/tooldata_mmap_backend.cc b/core/wasm_shims/tooldata/tooldata_mmap_backend.cc
index bc3220e..37dbcd9 100644
--- a/core/wasm_shims/tooldata/tooldata_mmap_backend.cc
+++ b/core/wasm_shims/tooldata/tooldata_mmap_backend.cc
@@ -4,6 +4,9 @@
 #include <cstdio>
 #include <unistd.h>
 
+// LinuxCNC source basis: src/emc/tooldata/tooldata_mmap.cc provides these
+// tool_mmap and indexed tool table entry points; this shim keeps them
+// available for WASM without native mmap.
 namespace {
 
 CANON_TOOL_TABLE tool_table[CANON_POCKETS_MAX];
diff --git a/core/wasm_shims/tooldata/tooldata_runtime_stubs.cc b/core/wasm_shims/tooldata/tooldata_runtime_stubs.cc
index 7ef3644..e2be052 100644
--- a/core/wasm_shims/tooldata/tooldata_runtime_stubs.cc
+++ b/core/wasm_shims/tooldata/tooldata_runtime_stubs.cc
@@ -3,6 +3,8 @@
 #include <cstring>
 #include <unistd.h>
 
+// LinuxCNC source basis: src/emc/tooldata/tooldata_nml.cc and tooldata_db.cc
+// provide the NML registration and external tool database entry points.
 namespace {
 
 constexpr int MAX_DB_PROGRAM_ARGS = 10;
diff --git a/test-linuxcnc-wasm-cmake-safe-probe.sh b/test-linuxcnc-wasm-cmake-safe-probe.sh
index 5e26399..e648929 100755
--- a/test-linuxcnc-wasm-cmake-safe-probe.sh
+++ b/test-linuxcnc-wasm-cmake-safe-probe.sh
@@ -918,6 +918,9 @@ tooldata_mmap_backend_shim=$(./list-linuxcnc-wasm-safe-shims.sh tooldata_mmap_ba
 grep -Fx "core/wasm_shims/tooldata/tooldata_mmap_backend.cc" <<<"$tooldata_mmap_backend_shim" >/dev/null
 tooldata_runtime_stubs_shim=$(./list-linuxcnc-wasm-safe-shims.sh tooldata_runtime_stubs.cc)
 grep -Fx "core/wasm_shims/tooldata/tooldata_runtime_stubs.cc" <<<"$tooldata_runtime_stubs_shim" >/dev/null
+grep -F 'LinuxCNC source basis: src/emc/tooldata/tooldata.hh declares the tooldata' core/wasm_shims/tooldata/tooldata.hh >/dev/null
+grep -F 'LinuxCNC source basis: src/emc/tooldata/tooldata_mmap.cc provides these' core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'LinuxCNC source basis: src/emc/tooldata/tooldata_nml.cc and tooldata_db.cc' core/wasm_shims/tooldata/tooldata_runtime_stubs.cc >/dev/null
 wasm_bridge_source=$(./list-linuxcnc-wasm-safe-project-sources.sh linuxcnc_canon_bridge.cpp)
 grep -Fx "core/src/linuxcnc_canon_bridge.cpp" <<<"$wasm_bridge_source" >/dev/null
 missing_shim_log=$(mktemp "${TMPDIR:-/tmp}/cnc_sim_missing_wasm_safe_shim.XXXXXX.log")