Index: generic/nsf.c
===================================================================
diff -u -r2dca7abdd5d83421b31b220bc6dabba1047d68fb -r929db54ebd7cf84befee362a94c1b9e1a32a041d
--- generic/nsf.c	(.../nsf.c)	(revision 2dca7abdd5d83421b31b220bc6dabba1047d68fb)
+++ generic/nsf.c	(.../nsf.c)	(revision 929db54ebd7cf84befee362a94c1b9e1a32a041d)
@@ -19690,16 +19690,27 @@
     return TCL_ERROR;
   }
 
+  /*
+   * Upon [interp create], set up NSF for the new child interp by running
+   * Nsf_Init()
+   */
+
   if (isCreateString(name)) {
+    Tcl_Obj *slaveCmdObj; 
+    Tcl_Interp *slavePtr;
+
     /*
-     * The command was an interp create, so perform an Nsf_Init() on
-     * the new interpreter.
+     * Tcl_InterpObjCmd() stores the newly created child interp's command name
+     * in the interp result store.
      */
-    Tcl_Interp *slave = Tcl_GetSlave(interp, ObjStr(objv[2]));
-    if (!slave) {
+
+    slaveCmdObj = Tcl_GetObjResult(interp);
+    slavePtr = Tcl_GetSlave(interp, ObjStr(slaveCmdObj));
+
+    if (!slavePtr) {
       return NsfPrintError(interp, "creation of slave interpreter failed");
     }
-    if (Nsf_Init(slave) == TCL_ERROR) {
+    if (Nsf_Init(slavePtr) == TCL_ERROR) {
       return TCL_ERROR;
     }
   }
Index: tests/interp.test
===================================================================
diff -u -r45e24b34c85bf0fc3e14db5250550100bd07ff31 -r929db54ebd7cf84befee362a94c1b9e1a32a041d
--- tests/interp.test	(.../interp.test)	(revision 45e24b34c85bf0fc3e14db5250550100bd07ff31)
+++ tests/interp.test	(.../interp.test)	(revision 929db54ebd7cf84befee362a94c1b9e1a32a041d)
@@ -740,4 +740,15 @@
   unset i
 }
 
+nx::test case nsf-interp-basics {
+  global i
+  set i [::nsf::interp create]
+  ? {$i eval {info commands ::nsf::is}} "::nsf::is"
+  ? {interp issafe $i} 0
+  ? {::nsf::interp create zzz} "zzz"
+  set i [::nsf::interp create -safe]
+  ? {$i eval {info commands ::nsf::is}} "::nsf::is"
+  ? {interp issafe $i} 1
+}
 
+