diff --git a/.agents/skills/lib_int.sh b/.agents/skills/lib_int.sh
index 5ccb8d2..09afdef 100644
--- a/.agents/skills/lib_int.sh
+++ b/.agents/skills/lib_int.sh
@@ -6,6 +6,8 @@
 #
 # Issue #17 item 4: the rule itself is lib_py/ints.py, which the loop runner
 # imports too (runner.py::_positive_int); these functions only call it.
+# They run `python3` from PATH (this file has no $PY when sourced alone):
+# without one, mam_int and mam_int_knob print nothing (rc 127).
 _MAM_INTS_PY="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/lib_py/ints.py"
 
 # mam_int <value> <min>