diff --git a/src/runtime/mapvfs.config b/src/runtime/mapvfs.config
index 6d27f938..10742289 100644
--- a/src/runtime/mapvfs.config
+++ b/src/runtime/mapvfs.config
@@ -27,6 +27,13 @@ tclkit86bi.exe  {punk8win.vfs punkbi kit}
 #1
 tclkit-win64-dyn.exe {punk8win.vfs punksys kit}
 
+#punk86: the Tcl 8.6 reference punk kit (8.6-behaviour checks - see src/tests/AGENTS.md and the
+#test-interpreter notes). Remapped 2026-07-21: the previous unmapped tclkit8613-era build had
+#fossilized (kit-stamped punk::args 0.1.0 winning unversioned requires while versioned requires
+#pulled modern modules - the runtests punk::args::define skew). Rebuilt from the 8.6.17 dyn
+#tclkit, matching the native Tcl86 test interpreter patchlevel (punksys stays on the 8.6.13 dyn).
+tclkit-win64-dyn-8617.exe {punk8win.vfs punk86 kit}
+
 #tclkit87a5.exe {punk86.vfs punk87} {punk.vfs punkmain}
 
 #TCL9