尽快推进：收紧tooldata外部DB边界

docs/linuxcnc-tooldata-source-map.md

@@ -37,6 +37,16 @@ source-link/shim guard only; it must not add CNC behavior and must not expand th
 | `test-linuxcnc-wasm-tooldata-mmap-symbols.sh` | Compares wasm mmap backend exports with LinuxCNC `tooldata_mmap.cc`. |
 | `test-linuxcnc-wasm-tooldata-runtime-symbols.sh` | Compares runtime stub exports with LinuxCNC `tooldata_db.cc` and `tooldata_nml.cc`. |
 
+## External DB Stub Boundaries
+
+- `core/wasm_shims/tooldata/tooldata_runtime_stubs.cc` must keep external DB services unavailable for browser-safe probes; it must not fork, exec, poll,
+  or keep a live external database process.
+- `tooldata_db_init()` must preserve the LinuxCNC `MAX_DB_PROGRAM_ARGS=10`, `strtok_r()` argument splitting, and `access(..., X_OK)` rejection edges from
+  `src/emc/tooldata/tooldata_db.cc` before returning `-1`.
+- `tooldata_db_getall()` must return `-1` while `db_live` is false, and
+  `tooldata_db_notify()` must return `0` without side effects while `db_live`
+  is false.
+
 ## Boundaries
 
 - Tool table files referenced by switchkins INI files are source coverage only;