diff --git a/wasm-port/docs/compatibility-validation.md b/wasm-port/docs/compatibility-validation.md
index 73deca8..5b97d7d 100644
--- a/wasm-port/docs/compatibility-validation.md
+++ b/wasm-port/docs/compatibility-validation.md
@@ -135,7 +135,8 @@ to reject invalid INI-derived parameter/tool-table file names through the OPFS
 path model after the names are parsed by the LinuxCNC-backed INI WASM SDK. It
 also verifies that explicit session parameter/tool-table file-name options
 override INI-derived names before OPFS text is copied into the LinuxCNC-backed
-WASM filesystem.
+WASM filesystem, and that absent INI file-name values use the default OPFS
+parameter/tool-table paths in a real browser session.
 
 The aggregate host smoke script builds the INI and interpreter-core WASM
 artifacts once, then runs the Node WASM smokes, the Node OPFS mock smoke, and
@@ -279,7 +280,8 @@ session snapshot custom filename handling plus envelope/path rejection
 for unsupported format/version, wrong session id, and invalid snapshot
 filenames, and a browser interpreter smoke that uses the same session bridge
 with real LinuxCNC INI WASM parsing before saving OPFS-backed parameter and
-tool-table text through vendored LinuxCNC file APIs.
+tool-table text through vendored LinuxCNC file APIs, including default OPFS
+path fallback when INI file-name values are absent.
 Full browser coverage, full SDK coverage, and richer machine-state validation
 remain future work.
 
diff --git a/wasm-port/tests/browser/interp_smoke.html b/wasm-port/tests/browser/interp_smoke.html
index c32a1cb..7911a9c 100644
--- a/wasm-port/tests/browser/interp_smoke.html
+++ b/wasm-port/tests/browser/interp_smoke.html
@@ -307,6 +307,18 @@
           toolTableWasmPath: "/work/browser-random-tool.tbl",
         },
       );
+      if (
+        loadedRandomSession.parameters.opfsPath !==
+        "linuxcnc/machines/browser-random-toolchanger/linuxcnc.var"
+      ) {
+        throw new Error(`unexpected default parameter path: ${loadedRandomSession.parameters.opfsPath}`);
+      }
+      if (
+        loadedRandomSession.toolTable.opfsPath !==
+        "linuxcnc/machines/browser-random-toolchanger/tool.tbl"
+      ) {
+        throw new Error(`unexpected default tool path: ${loadedRandomSession.toolTable.opfsPath}`);
+      }
       verifyExpectedOutput(
         "opfs_load_random_tool_table",
         loadedRandomSession.toolTable.result,