diff --git a/src/core/corelib.c b/src/core/corelib.c
index 24e24a60..a028cbb6 100644
--- a/src/core/corelib.c
+++ b/src/core/corelib.c
@@ -339,7 +339,10 @@ JANET_CORE_FN(janet_core_native,
 
 JANET_CORE_FN(janet_core_describe,
               "(describe x)",
-              "Returns a string that is a human-readable description of a value x.") {
+              "Returns a string that is a human-readable description of `x`. "
+              "For recursive data structures, the string returned contains a "
+              "more or less unique pointer value from which the identity of `x` "
+              "could be determined.") {
     JanetBuffer *b = janet_buffer(0);
     for (int32_t i = 0; i < argc; ++i)
         janet_description_b(b, argv[i]);