diff --git a/host/chez/converters.ss b/host/chez/converters.ss
index e8284c4..44ad8fb 100644
--- a/host/chez/converters.ss
+++ b/host/chez/converters.ss
@@ -121,5 +121,8 @@
 (def-var! "clojure.core" "symbol" jolt-symbol-new)
 (def-var! "clojure.core" "gensym" jolt-gensym)
 (def-var! "clojure.core" "int" jolt-int)
+;; long: same truncation as int in jolt's all-flonum model (seed core-long =
+;; math/trunc; char -> code point). Distinct cell so (long ...) resolves.
+(def-var! "clojure.core" "long" jolt-int)
 (def-var! "clojure.core" "double" jolt-double)
 (def-var! "clojure.core" "compare" jolt-compare)
diff --git a/host/chez/driver.janet b/host/chez/driver.janet
index 02c294e..0800c69 100644
--- a/host/chez/driver.janet
+++ b/host/chez/driver.janet
@@ -115,7 +115,13 @@
    # clojure.edn requires clojure.string; read-string/__read-tagged are the
    # reader.ss seams. The reader-arity's drain-reader is Janet-coupled (janet/type)
    # so it's a lazy gap on Chez — read-string/edn->value are the live path. jolt-r8ku.
-   ["clojure.edn" "src/jolt/clojure/edn.clj"]])
+   ["clojure.edn" "src/jolt/clojure/edn.clj"]
+   # clojure.set / clojure.pprint: pure Clojure over core. set = relational ops
+   # (union/intersection/difference/join/index/...); pprint = the minimal jolt
+   # shim (pprint -> prn + recognized dispatch vars, with-pprint-dispatch macro).
+   # jolt-j5vg, clojure.pprint Phase-2 parity.
+   ["clojure.set" "src/jolt/clojure/set.clj"]
+   ["clojure.pprint" "src/jolt/clojure/pprint.clj"]])
 
 (defn- sym-name [x]
   (when (and (struct? x) (= :symbol (get x :jolt/type))) (get x :name)))
diff --git a/host/chez/jolt-chez.janet b/host/chez/jolt-chez.janet
index 5a19180..80fc484 100644
--- a/host/chez/jolt-chez.janet
+++ b/host/chez/jolt-chez.janet
@@ -23,10 +23,11 @@
            "host/chez/ns.ss" "host/chez/post-prelude.ss" "host/chez/natives-meta.ss"
            "host/chez/natives-str.ss" "host/chez/records.ss"
            "host/chez/host-class.ss" "host/chez/io.ss"
-           "host/chez/inst-time.ss" "host/chez/reader.ss"
+           "host/chez/inst-time.ss" "host/chez/reader.ss" "host/chez/math.ss"
            "host/chez/host-static.ss" "host/chez/dot-forms.ss"
            "src/jolt/clojure/string.clj" "src/jolt/clojure/walk.clj"
-           "src/jolt/clojure/template.clj" "src/jolt/clojure/edn.clj"]
+           "src/jolt/clojure/template.clj" "src/jolt/clojure/edn.clj"
+           "src/jolt/clojure/set.clj" "src/jolt/clojure/pprint.clj"]
     (array/push parts (slurp f)))
   (string/slice (string (hash (string/join parts))) 0))
 
diff --git a/host/chez/math.ss b/host/chez/math.ss
new file mode 100644
index 0000000..1b902de
--- /dev/null
+++ b/host/chez/math.ss
@@ -0,0 +1,63 @@
+;; clojure.math (jolt-22vo) — Chez host shim over native flonum math.
+;;
+;; On the Janet seed clojure.math is registered as native math/ bindings
+;; (api.janet install-clojure-math!, jolt-h79), NOT a .clj file — so there's no
+;; source tier to emit. Chez provides its own def-var! shims here, one per
+;; clojure.math fn, over Chez's native procedures. The analyzer already knows the
+;; clojure.math ns exists (init interns the same fns on the Janet side), so a ref
+;; like clojure.math/sqrt lowers to a var-deref; these cells back it at runtime.
+;;
+;; jolt is all-flonum, so every result is a flonum (inputs arrive as flonums; Chez
+;; sqrt/sin/expt/... return flonums for flonum args). Semantics match the seed
+;; (Clojure 1.11 clojure.math): round = floor(x+0.5), rint = round-half-even,
+;; floor/ceil/floor-div return doubles, to-degrees/to-radians via PI.
+
+(define jolt-math-pi (acos -1.0))
+(define jolt-math-e (exp 1.0))
+
+(define (jolt-math-cbrt x)
+  ;; sign-aware so negative inputs stay real (expt of a negative flonum to a
+  ;; fractional power goes complex).
+  (if (< x 0.0)
+      (- (expt (- x) (/ 1.0 3.0)))
+      (expt x (/ 1.0 3.0))))
+
+(define (jolt-math-round x) (floor (+ x 0.5)))
+(define (jolt-math-signum x) (cond ((< x 0.0) -1.0) ((> x 0.0) 1.0) (else 0.0)))
+(define (jolt-math-to-degrees r) (/ (* r 180.0) jolt-math-pi))
+(define (jolt-math-to-radians d) (/ (* d jolt-math-pi) 180.0))
+(define (jolt-math-hypot a b) (sqrt (+ (* a a) (* b b))))
+(define (jolt-math-floor-div a b) (floor (/ a b)))
+(define (jolt-math-floor-mod a b) (- a (* b (floor (/ a b)))))
+
+(def-var! "clojure.math" "sqrt" sqrt)
+(def-var! "clojure.math" "cbrt" jolt-math-cbrt)
+(def-var! "clojure.math" "pow" expt)
+(def-var! "clojure.math" "exp" exp)
+(def-var! "clojure.math" "expm1" (lambda (x) (- (exp x) 1.0)))
+(def-var! "clojure.math" "log" log)
+(def-var! "clojure.math" "log10" (lambda (x) (log x 10.0)))
+(def-var! "clojure.math" "log1p" (lambda (x) (log (+ 1.0 x))))
+(def-var! "clojure.math" "sin" sin)
+(def-var! "clojure.math" "cos" cos)
+(def-var! "clojure.math" "tan" tan)
+(def-var! "clojure.math" "asin" asin)
+(def-var! "clojure.math" "acos" acos)
+(def-var! "clojure.math" "atan" atan)
+;; clojure.math/atan2 is atan2(y, x); Chez's 2-arg atan is (atan y x).
+(def-var! "clojure.math" "atan2" (lambda (y x) (atan y x)))
+(def-var! "clojure.math" "sinh" sinh)
+(def-var! "clojure.math" "cosh" cosh)
+(def-var! "clojure.math" "tanh" tanh)
+(def-var! "clojure.math" "floor" floor)
+(def-var! "clojure.math" "ceil" ceiling)
+(def-var! "clojure.math" "rint" round)
+(def-var! "clojure.math" "round" jolt-math-round)
+(def-var! "clojure.math" "signum" jolt-math-signum)
+(def-var! "clojure.math" "to-degrees" jolt-math-to-degrees)
+(def-var! "clojure.math" "to-radians" jolt-math-to-radians)
+(def-var! "clojure.math" "hypot" jolt-math-hypot)
+(def-var! "clojure.math" "floor-div" jolt-math-floor-div)
+(def-var! "clojure.math" "floor-mod" jolt-math-floor-mod)
+(def-var! "clojure.math" "E" jolt-math-e)
+(def-var! "clojure.math" "PI" jolt-math-pi)
diff --git a/host/chez/rt.ss b/host/chez/rt.ss
index 3050580..6972916 100644
--- a/host/chez/rt.ss
+++ b/host/chez/rt.ss
@@ -304,3 +304,7 @@
 ;; __read-tagged. Loads after inst-time.ss — __read-tagged reuses its #uuid/#inst
 ;; constructors, and the reader needs the full value/collection layer above.
 (load "host/chez/reader.ss")
+
+;; clojure.math (jolt-22vo): native flonum-math shims def-var!'d into the
+;; clojure.math ns. Self-contained (only def-var! + Chez math), order-independent.
+(load "host/chez/math.ss")
diff --git a/src/jolt/clojure/pprint.clj b/src/jolt/clojure/pprint.clj
index 20f4d49..4b8bbee 100644
--- a/src/jolt/clojure/pprint.clj
+++ b/src/jolt/clojure/pprint.clj
@@ -16,10 +16,15 @@
 (def ^:dynamic *print-pprint-dispatch* simple-dispatch)
 
 (defn pprint
-  "Print object readably followed by a newline. Writes to *out* (or the given
-  writer). Not a pretty-printer on jolt — no column-aware layout."
+  "Print object readably followed by a newline. Not a pretty-printer on jolt —
+  no column-aware layout. jolt routes all printing through the host output seam
+  (with-out-str captures it), and *out* is not a bindable var, so an explicit
+  writer arg is accepted for API compatibility but not honored — output goes to
+  the current output. (The old `(binding [*out* writer] ...)` never redirected
+  anything either, and made the defn fall back to the interpreter; dropping it
+  lets pprint compile cleanly, which the no-fallback Chez back end requires.)"
   ([object] (prn object))
-  ([object writer] (binding [*out* writer] (prn object))))
+  ([object _writer] (prn object)))
 
 (defmacro with-pprint-dispatch
   "Evaluate body with the given pprint dispatch selected. On jolt the dispatch is
diff --git a/test/chez/_stdlib.janet b/test/chez/_stdlib.janet
new file mode 100644
index 0000000..917bbd3
--- /dev/null
+++ b/test/chez/_stdlib.janet
@@ -0,0 +1,80 @@
+# jolt-j5vg / jolt-22vo / clojure.pprint — Phase-2 stdlib parity closeout.
+#
+#   clojure.set    — pure Clojure (src/jolt/clojure/set.clj) added to the Chez
+#                    prelude tier (driver.janet stdlib-ns-files).
+#   clojure.math   — native flonum-math shims (host/chez/math.ss) def-var!'d into
+#                    the clojure.math ns; the analyzer already knows the ns exists
+#                    (api.janet install-clojure-math!), so refs lower to var-deref.
+#   clojure.pprint — minimal shim on the prelude; pprint's 2-arity no longer uses
+#                    (binding [*out* writer] ...) (uncompilable on the no-fallback
+#                    Chez back end; *out* isn't a bindable var — output always goes
+#                    through the host seam).
+#
+# Outputs are order-stable (value-equality / scalars) so set/map iteration order
+# — which legitimately differs from build/jolt — never masquerades as a divergence.
+# Oracle = build/jolt.
+#
+#   janet test/chez/_stdlib.janet
+(def jolt-bin (or (os/getenv "JOLT_BIN") "bin/jolt-chez"))
+
+(def cases
+  [# --- clojure.math (jolt-22vo / jolt-h79) ---
+   ["(< 1.4142 (clojure.math/sqrt 2) 1.4143)"                       "true"]
+   ["(long (clojure.math/pow 2 10))"                                "1024"]
+   ["(long (clojure.math/tan 0))"                                   "0"]
+   ["(clojure.math/round 2.6)"                                      "3"]
+   ["(clojure.math/floor 2.9)"                                      "2"]
+   ["(clojure.math/signum -7.2)"                                    "-1"]
+   ["(< 3.14 (clojure.math/to-radians 180) 3.15)"                   "true"]
+   ["(< 3.14 clojure.math/PI 3.15)"                                 "true"]
+   ["(< 2.71 clojure.math/E 2.72)"                                  "true"]
+   ["(long (clojure.math/cbrt 27))"                                 "3"]
+   ["(< 4.6 (clojure.math/log 100) 4.7)"                            "true"]
+   # Chez has no native log10 (computed as log(x)/log(10)), so it can differ from
+   # the seed's C log10 in the last ulp (3 vs 2.9999…); range-check, don't pin.
+   ["(< 2.99 (clojure.math/log10 1000) 3.01)"                       "true"]
+   ["(do (require (quote [clojure.math :as m])) (long (m/hypot 3 4)))" "5"]
+   ["(mapv (comp long clojure.math/sqrt) [1 4])"                    "[1 2]"]
+   ["(long (clojure.math/atan2 0 1))"                               "0"]
+   # --- clojure.set (jolt-j5vg) ---
+   ["(do (require (quote [clojure.set :as s])) (= #{1 2 3 4} (s/union #{1 2} #{3 4})))"        "true"]
+   ["(do (require (quote [clojure.set :as s])) (= #{2} (s/intersection #{1 2} #{2 3})))"       "true"]
+   ["(do (require (quote [clojure.set :as s])) (= #{1} (s/difference #{1 2} #{2 3})))"         "true"]
+   ["(do (require (quote [clojure.set :as s])) (s/subset? #{1} #{1 2}))"                       "true"]
+   ["(do (require (quote [clojure.set :as s])) (s/superset? #{1 2} #{1}))"                     "true"]
+   ["(do (require (quote [clojure.set :as s])) (= {1 :a 2 :b} (s/map-invert {:a 1 :b 2})))"    "true"]
+   ["(do (require (quote [clojure.set :as s])) (= #{:a} (s/select keyword? #{:a})))"           "true"]
+   ["(do (require (quote [clojure.set :as s])) (= #{{:a 1 :b 2}} (s/join #{{:a 1}} #{{:b 2}})))" "true"]
+   ["(do (require (quote [clojure.set :as s])) (= {:b 1} (s/rename-keys {:a 1} {:a :b})))"     "true"]
+   ["(do (require (quote [clojure.set :as s])) (= 2 (count (s/index #{{:k 1} {:k 2}} [:k]))))" "true"]
+   # --- clojure.pprint (minimal shim) ---
+   ["(do (require (quote [clojure.pprint :as pp])) (= \"[1 2 3]\\n\" (with-out-str (pp/pprint [1 2 3]))))" "true"]
+   ["(do (require (quote [clojure.pprint :as pp])) (pp/with-pprint-dispatch pp/code-dispatch 42))" "42"]])
+
+(defn run-capture [bin expr]
+  (def proc (os/spawn [bin "-e" expr] :p {:out :pipe :err :pipe}))
+  (def out (ev/read (proc :out) 0x100000))
+  (def err (ev/read (proc :err) 0x100000))
+  (def code (os/proc-wait proc))
+  (def lines (filter (fn [l] (not (empty? l)))
+                     (string/split "\n" (string/trim (if out (string out) "")))))
+  [code (if (empty? lines) "" (last lines)) (string/trim (if err (string err) ""))])
+
+(var pass 0)
+(def fails @[])
+(each [expr expected] cases
+  (def [ocode oracle _] (run-capture "build/jolt" expr))
+  (def [code got err] (run-capture jolt-bin expr))
+  (cond
+    (not= ocode 0) (array/push fails [expr (string "ORACLE FAILED exit " ocode)])
+    (not= oracle expected) (array/push fails [expr (string "ORACLE MISMATCH want `" expected "` got `" oracle "`")])
+    (not= code 0) (array/push fails [expr (string "exit " code "; err: " err)])
+    (= got expected) (++ pass)
+    (array/push fails [expr (string "want `" expected "`, got `" got "`")])))
+
+(printf "\n_stdlib parity [%s]: %d/%d passed" jolt-bin pass (length cases))
+(when (> (length fails) 0)
+  (printf "%d FAIL(s):" (length fails))
+  (each [e m] fails (printf "  FAIL %s\n    %s" e m)))
+(flush)
+(os/exit (if (empty? fails) 0 1))
diff --git a/test/chez/run-corpus-prelude.janet b/test/chez/run-corpus-prelude.janet
index a3c5ca1..f7c0a1d 100644
--- a/test/chez/run-corpus-prelude.janet
+++ b/test/chez/run-corpus-prelude.janet
@@ -275,8 +275,14 @@
 # prelude. Lights up read / read+string / with-in-str (read) / read-string and
 # clojure.edn/read-string. (eval / load-string / runtime defmacro stay Phase-3 —
 # they need the compiler at runtime.) 2259.
+# Phase-2 stdlib closeout (jolt-j5vg / jolt-22vo / clojure.pprint): clojure.set +
+# clojure.pprint added to the prelude stdlib tier (driver.janet stdlib-ns-files),
+# clojure.math shimmed over Chez native flonum math (host/chez/math.ss), and the
+# missing `long` coercion def-var!'d (converters.ss). pprint's 2-arity dropped its
+# (binding [*out* writer] ...) (uncompilable on the no-fallback Chez back end —
+# *out* isn't a bindable var). 2280, crashes 191->170, 0 new divergences.
 # Strided runs scale down.
-(def base-floor (scan-number (or (os/getenv "JOLT_CHEZ_PRELUDE_FLOOR") "2259")))
+(def base-floor (scan-number (or (os/getenv "JOLT_CHEZ_PRELUDE_FLOOR") "2280")))
 (def floor (if (os/getenv "JOLT_CORPUS_LIMIT") 0 base-floor))
 (when (or (> (length diverged) 0) (< pass floor))
   (printf "REGRESSION: pass %d < floor %d or %d new divergence(s)" pass floor (length diverged)))