diff --git a/check-linuxcnc-tooldata-source-map.sh b/check-linuxcnc-tooldata-source-map.sh
index d182e41..298592e 100755
--- a/check-linuxcnc-tooldata-source-map.sh
+++ b/check-linuxcnc-tooldata-source-map.sh
@@ -40,6 +40,38 @@ grep -F 'emcStatus->io.tool.pocketPrepped' \
     "$linuxcnc_root/src/emc/tooldata/tool_watch.cc" >/dev/null
 grep -F '#define TOOL_MMAP_FILENAME ".tool.mmap"' \
     "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'bool tool_mmap_is_random_toolchanger(void)' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'ans = hptr->is_random_toolchanger;' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'int tool_mmap_creator(EMC_TOOL_STAT const * ptr,int random_toolchanger)' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'static int inited=0;' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'hptr->is_random_toolchanger = random_toolchanger;' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'hptr->last_index = 0;' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'int tool_mmap_user()' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'fprintf(stderr,"tool_mmap_user(): tool mmap not available\n");' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'return(-1);' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'void tool_mmap_close()' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'if (!tool_mmap_base) { return; }' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'int tooldata_last_index_get(void)' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'tool_mmap_mutex_give(); return -1;' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'int tooldata_find_index_for_tool(int toolno)' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'if (toolno == -1) {tool_mmap_mutex_give(); return -1;}' \
+    "$linuxcnc_root/src/emc/tooldata/tooldata_mmap.cc" >/dev/null
+grep -F 'if (!hptr->is_random_toolchanger && toolno == 0)' \
+    "$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[]' \
@@ -102,6 +134,38 @@ grep -F 'metadata:src/emc/tooldata/tooldata_nml.cc:source basis for wasm-safe to
 
 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 'bool mmap_created = false;' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'bool mmap_random_toolchanger = false;' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'bool mmap_creator_called = false;' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'int tool_mmap_creator(EMC_TOOL_STAT const *ptr, int random_toolchanger)' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'Error: tool_mmap_creator already called BYE' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'mmap_created = true;' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'mmap_random_toolchanger = random_toolchanger;' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'last_index = 0;' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'int tool_mmap_user(void)' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'tool_mmap_user(): tool mmap not available' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'void tool_mmap_close(void)' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'mmap_created = false;' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'bool tool_mmap_is_random_toolchanger(void)' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'return mmap_random_toolchanger;' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'int tooldata_last_index_get(void)' \
+    core/wasm_shims/tooldata/tooldata_mmap_backend.cc >/dev/null
+grep -F 'return -1;' \
+    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
 grep -F 'constexpr int MAX_DB_PROGRAM_ARGS = 10;' \
@@ -235,6 +299,10 @@ for phrase in [
     "access(..., X_OK)",
     "mmap tool table reader utility",
     "NML/mmap tool table watcher utility",
+    "mmap creator/user/close lifecycle",
+    "random-toolchanger flag",
+    "last-index unavailable return",
+    "in-memory replacement for native mmap",
     "inactive-DB return values",
     "./check-linuxcnc-tooldata-source-map.sh",
     "does not interpret G-code",
diff --git a/docs/linuxcnc-tooldata-source-map.md b/docs/linuxcnc-tooldata-source-map.md
index 077fa08..a11bd57 100644
--- a/docs/linuxcnc-tooldata-source-map.md
+++ b/docs/linuxcnc-tooldata-source-map.md
@@ -51,6 +51,17 @@ source-link/shim guard only; it must not add CNC behavior and must not expand th
   `tooldata_db_notify()` must return `0` without side effects while `db_live`
   is false.
 
+## Mmap Backend Boundaries
+
+- `core/wasm_shims/tooldata/tooldata_mmap_backend.cc` must preserve the
+  LinuxCNC `tooldata_mmap.cc` export surface for the mmap creator/user/close lifecycle while using an in-memory replacement for native mmap.
+- The mmap backend must keep the LinuxCNC random-toolchanger flag and
+  `last_index` initialization edges from `tool_mmap_creator()`, and
+  `tooldata_last_index_get()` must preserve the last-index unavailable return.
+- `tool_mmap_user()` must keep LinuxCNC's unavailable mmap failure boundary,
+  and `tool_mmap_close()` must clear the browser-safe in-memory state without
+  adding filesystem mmap behavior.
+
 ## Boundaries
 
 - Tool table files referenced by switchkins INI files are source coverage only;