diff --git a/host/chez/printing.ss b/host/chez/printing.ss
new file mode 100644
index 0000000..545b0d9
--- /dev/null
+++ b/host/chez/printing.ss
@@ -0,0 +1,83 @@
+;; readable printer + output seams (jolt-cf1q.3 Phase 2 inc B) — the __pr-str1 /
+;; __write / __with-out-str host seams the overlay's pr-str/pr/prn/print/println/
+;; *-str family is built on (jolt-core/clojure/core/20-coll.clj). They resolved to
+;; jolt-nil, so the whole print family hit the apply-jolt-nil crash bucket.
+;;
+;; jolt-pr-str (rt.ss) is STR-style: strings render raw. pr-str needs READABLE
+;; (pr) style: strings quoted+escaped at every nesting level. This adds the
+;; readable renderer; it mirrors jolt-pr-str but quotes strings and recurses into
+;; itself, delegating scalars (nil/bool/number/keyword/symbol/char/regex) to
+;; jolt-pr-str (already readable for those). The canonical ORDERED printer is
+;; still future work — unordered colls render in HAMT order, compared via `=`.
+
+;; inner string escape (no surrounding quotes): " \ newline tab return.
+(define (jolt-str-escape s)
+  (let loop ((cs (string->list s)) (acc '()))
+    (if (null? cs)
+        (list->string (reverse acc))
+        (loop (cdr cs)
+              (let ((c (car cs)))
+                (case c
+                  ((#\") (cons #\" (cons #\\ acc)))
+                  ((#\\) (cons #\\ (cons #\\ acc)))
+                  ((#\newline) (cons #\n (cons #\\ acc)))
+                  ((#\tab) (cons #\t (cons #\\ acc)))
+                  ((#\return) (cons #\r (cons #\\ acc)))
+                  (else (cons c acc))))))))
+
+(define (jolt-pr-readable x)
+  (cond
+    ((string? x) (string-append "\"" (jolt-str-escape x) "\""))
+    ;; pr renders the infinities / NaN long-form (Clojure .toString), at every
+    ;; nesting level — unlike the -e printer's inf/-inf/nan.
+    ((and (flonum? x) (fl= x +inf.0)) "Infinity")
+    ((and (flonum? x) (fl= x -inf.0)) "-Infinity")
+    ((and (flonum? x) (not (fl= x x))) "NaN")
+    ;; transients print as a cold tagged type (the seed routes this through a
+    ;; print-method multimethod; the readable fallback renders it directly).
+    ;; forward refs to transients.ss (loaded later) — resolved at call time.
+    ((jolt-transient? x)
+     (if (pvec? (jolt-transient-coll x)) "#<transient vector>" "#<transient map>"))
+    ((pvec? x)
+     (let ((acc '()))
+       (let loop ((i (fx- (pvec-count x) 1)))
+         (when (fx>=? i 0)
+           (set! acc (cons (jolt-pr-readable (pvec-nth-d x i jolt-nil)) acc))
+           (loop (fx- i 1))))
+       (string-append "[" (jolt-str-join acc) "]")))
+    ((pset? x)
+     (string-append "#{" (jolt-str-join (pset-fold x (lambda (e a) (cons (jolt-pr-readable e) a)) '())) "}"))
+    ((pmap? x)
+     (string-append "{" (jolt-str-join
+       (pmap-fold x (lambda (k v a)
+                      (cons (string-append (jolt-pr-readable k) " " (jolt-pr-readable v)) a)) '())) "}"))
+    ((empty-list-t? x) "()")
+    ((cseq? x)
+     (string-append "(" (jolt-str-join
+       (let loop ((s x) (acc '()))
+         (if (jolt-nil? s) (reverse acc)
+             (loop (jolt-seq (seq-more s)) (cons (jolt-pr-readable (seq-first s)) acc))))) ")"))
+    (else (jolt-pr-str x))))
+
+;; __pr-str1: render ONE value readably (the overlay's pr-str joins these).
+(define (jolt-pr-str1 x) (jolt-pr-readable x))
+
+;; __write: push a string to *out* (current-output-port, so __with-out-str's
+;; redirect captures it). Returns nil.
+(define (jolt-write s) (display s) jolt-nil)
+
+;; __with-out-str: run a jolt thunk with *out* rebound to a string port, return
+;; the captured text.
+(define (jolt-with-out-str thunk)
+  (with-output-to-string (lambda () (jolt-invoke thunk))))
+
+;; __eprint / __eprintf: stderr seams.
+(define (jolt-eprint s) (display s (current-error-port)) jolt-nil)
+(define (jolt-eprintf fmt . args)
+  (apply fprintf (current-error-port) fmt args) jolt-nil)
+
+(def-var! "clojure.core" "__pr-str1" jolt-pr-str1)
+(def-var! "clojure.core" "__write" jolt-write)
+(def-var! "clojure.core" "__with-out-str" jolt-with-out-str)
+(def-var! "clojure.core" "__eprint" jolt-eprint)
+(def-var! "clojure.core" "__eprintf" jolt-eprintf)
diff --git a/host/chez/rt.ss b/host/chez/rt.ss
index cd1696f..0fbc13e 100644
--- a/host/chez/rt.ss
+++ b/host/chez/rt.ss
@@ -166,11 +166,21 @@
 ;; natives. Over the seq layer + jolt-compare, so loaded after converters.ss.
 (load "host/chez/natives-seq.ss")
 
+;; readable printer + output seams (jolt-9zhh, Phase 2 inc B): __pr-str1/__write/
+;; __with-out-str/__eprint/__eprintf — the host seams the overlay print family
+;; (pr-str/pr/prn/print/println/*-str) is built on. After converters.ss (uses
+;; jolt-pr-str/jolt-str-join) + seq.ss (jolt-invoke).
+(load "host/chez/printing.ss")
+
 ;; collection constructors + rand (jolt-agw6, Phase 2 inc A): bind the public
 ;; clojure.core names hash-map/hash-set/array-map/set/rand to the existing
 ;; pmap/pset ctors. After collections.ss (the ctors) + seq.ss (seq->list).
 (load "host/chez/natives-coll.ss")
 
+;; bit ops + parse-long/parse-double (jolt-cf1q.3 inc C): host-coupled scalar
+;; seed natives over the all-flonum number model.
+(load "host/chez/natives-num.ss")
+
 ;; multimethods (jolt-9ls5): defmulti/defmethod dispatch runtime. Needs jolt-invoke
 ;; (seq.ss), jolt=/key-hash/jolt-hash-map (collections.ss), jolt-atom? (atoms.ss),
 ;; jolt-pr-str (above), and the var-cell machinery — so loaded last.