diff --git a/host/chez/host-static-classes.ss b/host/chez/host-static-classes.ss
index eb35534..deb5d40 100644
--- a/host/chez/host-static-classes.ss
+++ b/host/chez/host-static-classes.ss
@@ -535,6 +535,24 @@
                    ((string=? iface "IFn")
                     (or (procedure? val) (keyword? val) (symbol-t? val)
                         (pmap? val) (pset? val) (pvec? val)))
+                   ;; host-class interfaces libraries branch on (data.json, etc.).
+                   ;; Matched by last segment, so java.util.Map and Map both hit.
+                   ((string=? iface "Named") (or (keyword? val) (symbol-t? val)))
+                   ((string=? iface "CharSequence") (string? val))
+                   ((string=? iface "Number") (number? val))
+                   ((string=? iface "Map") (or (pmap? val) (htable-sorted-map? val)))
+                   ((string=? iface "Set") (or (pset? val) (htable-sorted-set? val)))
+                   ;; a Java List is a vector or a seq/list — not a set or map.
+                   ((string=? iface "List")
+                    (or (and (pvec? val) (not (jolt-map-entry? val)))
+                        (cseq? val) (empty-list-t? val) (jolt-lazyseq? val)))
+                   ;; a Java Collection is any of those plus a set — but NOT a map.
+                   ((string=? iface "Collection")
+                    (or (pvec? val) (pset? val) (cseq? val) (empty-list-t? val)
+                        (jolt-lazyseq? val) (htable-sorted-set? val)))
+                   ((string=? iface "Associative")
+                    (or (pmap? val) (htable-sorted-map? val)
+                        (and (pvec? val) (not (jolt-map-entry? val)))))
                    (else 'none))))
         (if (eq? hit 'none) 'pass (if hit #t #f))))))
 
diff --git a/test/chez/corpus.edn b/test/chez/corpus.edn
index fa60339..e476c58 100644
--- a/test/chez/corpus.edn
+++ b/test/chez/corpus.edn
@@ -2971,4 +2971,14 @@
   {:suite "protocols / extend on host classes" :label "dispatch by java.util.Map/Collection/CharSequence" :expected "[:map :coll :str :obj]" :actual "(do (defprotocol W (-w [x])) (extend java.util.Map W {:-w (fn [_] :map)}) (extend java.util.Collection W {:-w (fn [_] :coll)}) (extend java.lang.CharSequence W {:-w (fn [_] :str)}) (extend java.lang.Object W {:-w (fn [_] :obj)}) [(-w {:a 1}) (-w [1 2]) (-w \"s\") (-w 42)])"}
   {:suite "protocols / extend on host classes" :label "satisfies? via java.util.Map" :expected "true" :actual "(do (defprotocol Q (qq [x])) (extend java.util.Map Q {:qq (fn [_] :m)}) (satisfies? Q {}))"}
   {:suite "protocols / extend on host classes" :label "extends? on a qualified host class" :expected "true" :actual "(do (defprotocol Qe (qe [x])) (extend java.util.Collection Qe {:qe (fn [_] :c)}) (extends? Qe java.util.Collection))"}
+  {:suite "interop / instance? on host interfaces" :label "keyword is Named" :expected "true" :actual "(instance? clojure.lang.Named :a)"}
+  {:suite "interop / instance? on host interfaces" :label "string is CharSequence" :expected "true" :actual "(instance? java.lang.CharSequence \"s\")"}
+  {:suite "interop / instance? on host interfaces" :label "number is Number" :expected "true" :actual "(instance? java.lang.Number 42)"}
+  {:suite "interop / instance? on host interfaces" :label "map is java.util.Map" :expected "true" :actual "(instance? java.util.Map {:a 1})"}
+  {:suite "interop / instance? on host interfaces" :label "vector is java.util.List" :expected "true" :actual "(instance? java.util.List [1 2])"}
+  {:suite "interop / instance? on host interfaces" :label "list is java.util.Collection" :expected "true" :actual "(instance? java.util.Collection (list 1))"}
+  {:suite "interop / instance? on host interfaces" :label "set is java.util.Set" :expected "true" :actual "(instance? java.util.Set #{1})"}
+  {:suite "interop / instance? on host interfaces" :label "map is not a Collection" :expected "false" :actual "(instance? java.util.Collection {:a 1})"}
+  {:suite "interop / instance? on host interfaces" :label "vector is Associative" :expected "true" :actual "(instance? clojure.lang.Associative [1])"}
+  {:suite "interop / instance? on host interfaces" :label "string is not Number" :expected "false" :actual "(instance? java.lang.Number \"s\")"}
 ]