diff --git a/packages/runtime/src/scr_array.c b/packages/runtime/src/scr_array.c
index cd9c45005..c0d99be52 100644
--- a/packages/runtime/src/scr_array.c
+++ b/packages/runtime/src/scr_array.c
@@ -13,8 +13,7 @@ long scr_arr_live_count(void) { return scr_live_arrays; }
 #endif
 
 static void scr_arr_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* JS would return undefined for an OOB read and create holes for a far OOB
@@ -23,10 +22,8 @@ static void scr_arr_oom(void) {
 static void scr_arr_trap_oob(double i, size_t len) {
   char buf[32];
   scr_f64_to_str(i, buf);
-  fprintf(stderr,
-          "scriptc: RangeError: array index %s out of bounds (length %zu)\n",
-          buf, len);
-  abort();
+  scr_trap_fmt("scriptc: RangeError: array index %s out of bounds (length %zu)\n",
+               buf, len);
 }
 
 /* Validate i as an element index. limit is a->len for reads, a->len + 1 for
@@ -264,8 +261,7 @@ double scr_arr_push_ref(ScrArr *a, void *v) {
 
 static uint64_t scr_arr_pop_slot(ScrArr *a) {
   if (a->len == 0) {
-    fputs("scriptc: RangeError: pop() on an empty array\n", stderr);
-    abort();
+    scr_trap("scriptc: RangeError: pop() on an empty array\n");
   }
   return a->data[--a->len];
 }
@@ -283,8 +279,7 @@ void *scr_arr_pop_ref(ScrArr *a) { return scr_slot_to_ptr(scr_arr_pop_slot(a));
  * ownership moves out to the caller (no retain). */
 static uint64_t scr_arr_shift_slot(ScrArr *a) {
   if (a->len == 0) {
-    fputs("scriptc: internal error: shift() on an empty array\n", stderr);
-    abort();
+    scr_trap("scriptc: internal error: shift() on an empty array\n");
   }
   uint64_t s = a->data[0];
   a->len--;
@@ -456,8 +451,7 @@ ScrStr *scr_arr_join(ScrArr *a, ScrStr *sep) {
       case SCR_ELEM_BYTES:
       case SCR_ELEM_REF:
         /* The compiler rejects join on ref-element arrays (SC1090). */
-        fputs("scriptc: internal error: join on a ref-element array\n", stderr);
-        abort();
+        scr_trap("scriptc: internal error: join on a ref-element array\n");
     }
   }
   ScrStr *out = scr_str_new(buf, len);
diff --git a/packages/runtime/src/scr_assert.c b/packages/runtime/src/scr_assert.c
index 5e68ba515..dd281db41 100644
--- a/packages/runtime/src/scr_assert.c
+++ b/packages/runtime/src/scr_assert.c
@@ -32,8 +32,7 @@
 #include <string.h>
 
 static void scr_assert_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* ── a tiny append-only byte buffer for message assembly ─────────────── */
diff --git a/packages/runtime/src/scr_bytes.c b/packages/runtime/src/scr_bytes.c
index 88c4996c2..a24e24135 100644
--- a/packages/runtime/src/scr_bytes.c
+++ b/packages/runtime/src/scr_bytes.c
@@ -17,8 +17,7 @@ long scr_bytes_live_count(void) { return scr_live_bytes; }
 #endif
 
 static void scr_bytes_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 size_t scr_bytes_elem_size(ScrBytesElem elem) {
@@ -98,10 +97,8 @@ static size_t scr_bytes_check_index(const ScrBytes *b, double i) {
   if (!(i >= 0) || i != trunc(i) || i >= (double)b->len) {
     char buf[32];
     scr_f64_to_str(i, buf);
-    fprintf(stderr,
-            "scriptc: RangeError: typed array index %s out of bounds (length %zu)\n",
-            buf, b->len);
-    abort();
+    scr_trap_fmt("scriptc: RangeError: typed array index %s out of bounds (length %zu)\n",
+                 buf, b->len);
   }
   return (size_t)i;
 }
diff --git a/packages/runtime/src/scr_bytes_io.c b/packages/runtime/src/scr_bytes_io.c
index 390312de0..2376c09b8 100644
--- a/packages/runtime/src/scr_bytes_io.c
+++ b/packages/runtime/src/scr_bytes_io.c
@@ -12,8 +12,7 @@
 #include <string.h>
 
 static void scr_bytes_io_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* ── fs (the Buffer forms of scr_lib.c's utf8 pair) ────────────────────── */
diff --git a/packages/runtime/src/scr_closure.c b/packages/runtime/src/scr_closure.c
index 6884b15af..6f8212fca 100644
--- a/packages/runtime/src/scr_closure.c
+++ b/packages/runtime/src/scr_closure.c
@@ -146,8 +146,7 @@ void *scr_box_get_ref(ScrBox *b) {
   case SCR_BOX_OBJ:
     return b->obj_retain(p);
   default:
-    fputs("scriptc: internal error: box_get_ref on a scalar box\n", stderr);
-    abort();
+    scr_trap("scriptc: internal error: box_get_ref on a scalar box\n");
   }
 }
 
diff --git a/packages/runtime/src/scr_console.c b/packages/runtime/src/scr_console.c
index 71cf0b41b..2cfee65fe 100644
--- a/packages/runtime/src/scr_console.c
+++ b/packages/runtime/src/scr_console.c
@@ -14,6 +14,26 @@
 static long scr_abandoned_fibers = 0;
 void scr_note_abandoned_fibers(long n) { scr_abandoned_fibers = n; }
 
+#ifndef SCR_CORE
+/* The trap funnel's EXECUTABLE expansion: exactly the historical
+ * fputs/vfprintf-to-stderr + abort every trap site used to open-code — the
+ * default lane's bytes and behavior are unchanged by construction. Core
+ * builds (-DSCR_CORE) get the sink-routing definitions from scr_core.c
+ * instead; this pair compiles out there. */
+_Noreturn void scr_trap(const char *msg) {
+  fputs(msg, stderr);
+  abort();
+}
+
+_Noreturn void scr_trap_fmt(const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  vfprintf(stderr, fmt, ap);
+  va_end(ap);
+  abort();
+}
+#endif /* !SCR_CORE */
+
 #ifdef SCR_RC_AUDIT
 extern long scr_str_live_count(void);     /* scr_string.c */
 extern long scr_arr_live_count(void);     /* scr_array.c */
diff --git a/packages/runtime/src/scr_core.c b/packages/runtime/src/scr_core.c
new file mode 100644
index 000000000..0ef49b1f5
--- /dev/null
+++ b/packages/runtime/src/scr_core.c
@@ -0,0 +1,221 @@
+/* Core (library) mode support: the panic sink, the poisoned-core flag, the
+ * outbound-result arena, the reset registry, and the sink-routing trap
+ * funnel. Linked ONLY into core artifacts (every TU of a core archive
+ * compiles with -DSCR_CORE); executable builds never contain this file —
+ * their funnel expansion lives in scr_console.c and their session teardown
+ * stays atexit-driven.
+ *
+ * The profile-NAMED symbols (init, sink registration, reset, collect) are
+ * emitted in the program TU and delegate here, so this file stays
+ * profile-agnostic and the program TU carries every profile-named symbol —
+ * one place for the conformance symbol audit to look.
+ *
+ * State after a sink call: none is legal. The trap fired mid-operation with
+ * no unwinding — heap, arena, and collector state are unspecified; the core
+ * is POISONED. Every runtime-touching entry prologue aborts on the flag
+ * (deterministic, never heap corruption); recovery is process restart. */
+#include "scr_runtime.h"
+
+#ifdef SCR_CORE
+
+#include <stdio.h>
+#include <stdlib.h>
+
+/* ── sink registration + poison ───────────────────────────────────────── */
+
+static ScrCoreSinkFn scr_core_sink = NULL;
+static void *scr_core_sink_ctx = NULL;
+static bool scr_core_poisoned = false;
+
+void scr_core_set_sink(ScrCoreSinkFn fn, void *ctx) {
+  /* Latest registration wins; re-registration is permitted before a trap.
+   * Deliberately NOT poison-guarded: a pure store, touching no runtime
+   * state — but a poisoned core's entries abort regardless of the sink. */
+  scr_core_sink = fn;
+  scr_core_sink_ctx = ctx;
+}
+
+/* ── the trap funnel, core expansion ──────────────────────────────────────
+ * Poison first (the sink may longjmp to a host frame below the entry — the
+ * conforming survival pattern), then deliver exactly once, then abort:
+ * before registration, or if the sink returns (the ruled host-contract
+ * violation). The address is the funnel frame's return address — the trap
+ * site — 0 where the toolchain cannot supply one. */
+
+#if defined(__GNUC__) || defined(__clang__)
+#define SCR_TRAP_ADDR() ((uint64_t)(uintptr_t)__builtin_return_address(0))
+#else
+#define SCR_TRAP_ADDR() ((uint64_t)0)
+#endif
+
+static _Noreturn void scr_core_trap_deliver(const char *msg, size_t len, uint64_t addr) {
+  scr_core_poisoned = true;
+  if (scr_core_sink != NULL) {
+    scr_core_sink(scr_core_sink_ctx, (const uint8_t *)msg, len, addr);
+  }
+  abort();
+}
+
+__attribute__((noinline)) _Noreturn void scr_trap(const char *msg) {
+  scr_core_trap_deliver(msg, strlen(msg), SCR_TRAP_ADDR());
+}
+
+__attribute__((noinline)) _Noreturn void scr_trap_fmt(const char *fmt, ...) {
+  static char buf[512]; /* no malloc on the invariant-failure path */
+  va_list ap;
+  va_start(ap, fmt);
+  int n = vsnprintf(buf, sizeof buf, fmt, ap);
+  va_end(ap);
+  size_t len = n < 0 ? 0 : (size_t)n >= sizeof buf ? sizeof buf - 1 : (size_t)n;
+  scr_core_trap_deliver(buf, len, SCR_TRAP_ADDR());
+}
+
+/* ── entry prologues ──────────────────────────────────────────────────── */
+
+void scr_core_entry(bool reset_arena) {
+  /* A poisoned core's entries abort deterministically — never through the
+   * sink again (it received its exactly-once message when the trap fired),
+   * never into a heap whose invariants already failed. */
+  if (scr_core_poisoned) abort();
+  if (reset_arena) scr_core_arena_reset();
+}
+
+/* ── the outbound-result arena ────────────────────────────────────────────
+ * Buffer-class results (string/bytes) MOVE in here; the host reads through
+ * borrowed pointers until the arena resets (per-entry under the auto
+ * posture, host-cycled when the profile declares a reset symbol; init and
+ * collect always reset). */
+
+typedef struct {
+  void *v;
+  bool is_str; /* ScrStr vs ScrBytes — picks the release */
+} ScrCoreArenaEnt;
+
+static ScrCoreArenaEnt *scr_core_arena = NULL;
+static size_t scr_core_arena_n = 0, scr_core_arena_cap = 0;
+
+static void scr_core_arena_keep(void *v, bool is_str) {
+  if (scr_core_arena_n == scr_core_arena_cap) {
+    scr_core_arena_cap = scr_core_arena_cap ? scr_core_arena_cap * 2 : 16;
+    scr_core_arena = realloc(scr_core_arena, scr_core_arena_cap * sizeof *scr_core_arena);
+    if (!scr_core_arena) scr_trap("scriptc: out of memory\n");
+  }
+  scr_core_arena[scr_core_arena_n].v = v;
+  scr_core_arena[scr_core_arena_n].is_str = is_str;
+  scr_core_arena_n++;
+}
+
+void scr_core_arena_reset(void) {
+  for (size_t i = 0; i < scr_core_arena_n; i++) {
+    if (scr_core_arena[i].is_str) scr_str_release((ScrStr *)scr_core_arena[i].v);
+    else scr_bytes_release((ScrBytes *)scr_core_arena[i].v);
+  }
+  scr_core_arena_n = 0;
+}
+
+void scr_core_collect(void) {
+  scr_core_arena_reset();
+  scr_collect_cycles();
+}
+
+/* ── marshalling helpers (both emissions call exactly these) ──────────── */
+
+ScrStr *scr_core_str_in(const uint8_t *p, size_t len) {
+  return scr_str_new((const char *)p, len);
+}
+
+ScrBytes *scr_core_bytes_in(const uint8_t *p, size_t len) {
+  ScrBytes *b = scr_bytes_new(SCR_BYTES_U8, (double)len);
+  if (b == NULL) {
+    /* scr_bytes_new throws only for lengths past 2^53-1 — an impossible
+     * host buffer; funnel the contract violation instead of a NULL deref. */
+    scr_exc_clear();
+    scr_trap("scriptc: core inbound bytes length out of range\n");
+  }
+  if (len > 0) memcpy(b->data, p, len);
+  return b;
+}
+
+void scr_core_str_out(ScrStr *s, const uint8_t **out, size_t *out_len) {
+  scr_core_arena_keep(s, true);
+  *out = (const uint8_t *)s->data; /* NUL-terminated after len (ScrStr layout) */
+  *out_len = s->len;
+}
+
+void scr_core_bytes_out(ScrBytes *b, const uint8_t **out, size_t *out_len) {
+  scr_core_arena_keep(b, false);
+  *out = b->data; /* elem is always u8 at the boundary (v1 bytes class) */
+  *out_len = b->len;
+}
+
+/* ── the reset registry + session reset ─────────────────────────────────
+ * Where an executable's always-linked units atexit() their lazy teardowns,
+ * core builds register here (scr_atexit in scr_runtime.h): registered
+ * once, drained on EVERY reset — re-registration guards in the units stay
+ * satisfied because the entry persists. */
+
+#define SCR_CORE_MAX_RESETS 32
+static void (*scr_core_resets[SCR_CORE_MAX_RESETS])(void);
+static size_t scr_core_nresets = 0;
+
+void scr_core_register_reset(void (*fn)(void)) {
+  for (size_t i = 0; i < scr_core_nresets; i++) {
+    if (scr_core_resets[i] == fn) return;
+  }
+  if (scr_core_nresets == SCR_CORE_MAX_RESETS) {
+    scr_trap("scriptc: internal error: core reset registry overflow\n");
+  }
+  scr_core_resets[scr_core_nresets++] = fn;
+}
+
+#ifdef SCR_RC_AUDIT
+extern long scr_str_live_count(void);     /* scr_string.c */
+extern long scr_arr_live_count(void);     /* scr_array.c */
+extern long scr_map_live_count(void);     /* scr_map.c */
+extern long scr_box_live_count(void);     /* scr_closure.c */
+extern long scr_closure_live_count(void); /* scr_closure.c */
+extern long scr_obj_live_count(void);     /* scr_object.c */
+extern long scr_union_live_count(void);   /* scr_union.c */
+extern long scr_dyn_live_count(void);     /* scr_json.c */
+extern long scr_bytes_live_count(void);   /* scr_bytes.c */
+
+/* The per-session heap-emptiness assertion (the audit flavor's determinism
+ * seam): after a full reset the live counters must all read zero, or the
+ * previous session leaked. A failure is a TRAP through the sink — the
+ * executable audit's _Exit(99) stays exe-lane-only. */
+static void scr_core_audit_zero(void) {
+  long strings = scr_str_live_count(), arrays = scr_arr_live_count(),
+       maps = scr_map_live_count(), boxes = scr_box_live_count(),
+       closures = scr_closure_live_count(), objects = scr_obj_live_count(),
+       unions = scr_union_live_count(), dyns = scr_dyn_live_count(),
+       bytes = scr_bytes_live_count();
+  if (strings != 0 || arrays != 0 || maps != 0 || boxes != 0 || closures != 0 ||
+      objects != 0 || unions != 0 || dyns != 0 || bytes != 0) {
+    scr_trap_fmt(
+        "scriptc CORE RC AUDIT FAILED: %ld heap string(s), %ld array(s), "
+        "%ld map(s), %ld box(es), %ld closure(s), %ld object(s), "
+        "%ld union(s), %ld dyn value(s), %ld bytes value(s) live across re-init\n",
+        strings, arrays, maps, boxes, closures, objects, unions, dyns, bytes);
+  }
+}
+#endif /* SCR_RC_AUDIT */
+
+extern void scr_lib_core_cleanup(void); /* scr_lib.c: the interned process values */
+
+void scr_core_reset(void) {
+  /* Called by the generated init entry AFTER the program TU released and
+   * zeroed its globals (run-once guards included) — the same order the
+   * executable exit path runs: library cleanup → cycle collection → RC
+   * audit. Everything here is re-runnable; the first call is a cheap
+   * no-op pass. */
+  scr_exc_clear();
+  scr_core_arena_reset();
+  for (size_t i = 0; i < scr_core_nresets; i++) scr_core_resets[i]();
+  scr_lib_core_cleanup();
+  scr_collect_cycles();
+#ifdef SCR_RC_AUDIT
+  scr_core_audit_zero();
+#endif
+}
+
+#endif /* SCR_CORE */
diff --git a/packages/runtime/src/scr_cycle.c b/packages/runtime/src/scr_cycle.c
index 3bbffd894..9ae4788ca 100644
--- a/packages/runtime/src/scr_cycle.c
+++ b/packages/runtime/src/scr_cycle.c
@@ -39,8 +39,7 @@
 #define SCR_RC(obj) (*(size_t *)(obj))
 
 static void scr_cyc_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 void *scr_cyc_alloc(size_t size, ScrTraceFn trace, ScrCycFreeFn free_fn) {
diff --git a/packages/runtime/src/scr_error.c b/packages/runtime/src/scr_error.c
index c1855aa7b..90e67ca1d 100644
--- a/packages/runtime/src/scr_error.c
+++ b/packages/runtime/src/scr_error.c
@@ -14,8 +14,7 @@
 #include <stdlib.h>
 
 static void scr_error_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 static bool scr_error_traced = false;
@@ -247,8 +246,7 @@ void scr_undef_global_read(ScrStr *name) {
   size_t len = name->len + sizeof suffix - 1;
   char *msg = malloc(len + 1);
   if (!msg) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   memcpy(msg, name->data, name->len);
   memcpy(msg + name->len, suffix, sizeof suffix);
diff --git a/packages/runtime/src/scr_events_emitter.c b/packages/runtime/src/scr_events_emitter.c
index d6e7afc0b..c73eb81a1 100644
--- a/packages/runtime/src/scr_events_emitter.c
+++ b/packages/runtime/src/scr_events_emitter.c
@@ -54,8 +54,7 @@
 #endif
 
 static void scr_ee_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* One registered listener. Shared between the live list and emit
diff --git a/packages/runtime/src/scr_exception.c b/packages/runtime/src/scr_exception.c
index f191b7758..b91f9992b 100644
--- a/packages/runtime/src/scr_exception.c
+++ b/packages/runtime/src/scr_exception.c
@@ -60,8 +60,7 @@ void scr_exc_clear(void) { scr_exc_reset(); }
 ScrCaught *scr_exc_take(void) {
   ScrCaught *c = calloc(1, sizeof *c);
   if (!c) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   c->rc = 1;
   c->kind = scr_exc_kind;
@@ -154,6 +153,70 @@ ScrStr *scr_caught_to_string(const ScrCaught *c) {
   return scr_str_new("", 0);
 }
 
+#ifdef SCR_CORE
+/* An exception that escaped user code into a generated entry wrapper: the
+ * host contract is that declared entries do not throw, so an escape is a
+ * contract-shaped failure exactly like a trap. Render the same "Uncaught
+ * ..." first line the executable epilogue prints (scr_exc_print_uncaught's
+ * arms, buffer-writing), release the payload, and route the text through
+ * the trap funnel — one failure channel at the boundary. */
+void scr_core_check_exc(void) {
+  if (!scr_exc_pending()) return;
+  static char buf[1024]; /* the message is copied out before the payload dies */
+  size_t n = 0;
+  const char prefix[] = "Uncaught ";
+  memcpy(buf, prefix, sizeof prefix - 1);
+  n = sizeof prefix - 1;
+  const size_t cap = sizeof buf - 2; /* room for '\n' + NUL */
+  switch (scr_exc_kind) {
+  case SCR_EXC_F64:
+    n += scr_f64_to_str(scr_exc_f64, buf + n);
+    break;
+  case SCR_EXC_BOOL: {
+    const char *b = scr_exc_bool ? "true" : "false";
+    size_t bl = strlen(b);
+    memcpy(buf + n, b, bl);
+    n += bl;
+    break;
+  }
+  case SCR_EXC_STR: {
+    const ScrStr *s = (const ScrStr *)scr_exc_payload;
+    size_t take = s->len > cap - n ? cap - n : s->len;
+    memcpy(buf + n, s->data, take);
+    n += take;
+    break;
+  }
+  case SCR_EXC_OBJ:
+    if (scr_error_is(scr_exc_payload)) {
+      ScrStr *s = scr_error_to_string((ScrError *)scr_exc_payload);
+      size_t take = s->len > cap - n ? cap - n : s->len;
+      memcpy(buf + n, s->data, take);
+      n += take;
+      scr_str_release(s);
+      break;
+    }
+    /* fall through: non-Error hierarchy objects render like other refs */
+  case SCR_EXC_REF: {
+    const char obj[] = "[object]";
+    memcpy(buf + n, obj, sizeof obj - 1);
+    n += sizeof obj - 1;
+    break;
+  }
+  case SCR_EXC_NONE:
+  case SCR_EXC_GENRET: { /* unreachable through the pending() gate */
+    const char none[] = "(no exception)";
+    memcpy(buf + n, none, sizeof none - 1);
+    n += sizeof none - 1;
+    break;
+  }
+  }
+  buf[n++] = '\n';
+  buf[n] = '\0';
+  scr_exc_reset(); /* the payload is released before the funnel poisons */
+  scr_trap(buf);
+}
+#endif /* SCR_CORE */
+
 void scr_throw_f64(double v) {
   scr_exc_reset();
   scr_exc_kind = SCR_EXC_F64;
diff --git a/packages/runtime/src/scr_inspect.c b/packages/runtime/src/scr_inspect.c
index e55a8412c..9b4decbab 100644
--- a/packages/runtime/src/scr_inspect.c
+++ b/packages/runtime/src/scr_inspect.c
@@ -31,8 +31,7 @@
 #include <string.h>
 
 static void insp_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* ── a tiny append-only byte buffer ──────────────────────────────────── */
diff --git a/packages/runtime/src/scr_json.c b/packages/runtime/src/scr_json.c
index aae1f7e18..736f21347 100644
--- a/packages/runtime/src/scr_json.c
+++ b/packages/runtime/src/scr_json.c
@@ -36,8 +36,7 @@ long scr_dyn_live_count(void) { return scr_live_dyns; }
 #endif
 
 static void scr_json_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* ── output buffer ─────────────────────────────────────────────────────
@@ -421,8 +420,7 @@ void scr_dyn_handle_install(ScrDynHandleTag tag, const ScrDynHandleOps *ops) {
 static const ScrDynHandleOps *scr_dyn_handle_ops(ScrDynHandleTag tag) {
   const ScrDynHandleOps *ops = scr_dynh_ops[tag];
   if (!ops) {
-    fputs("scriptc: internal error: dyn handle ops not installed\n", stderr);
-    abort();
+    scr_trap("scriptc: internal error: dyn handle ops not installed\n");
   }
   return ops;
 }
@@ -501,8 +499,7 @@ static ScrDynThisEnt *scr_dyn_this_grow(void) {
     size_t cap = scr_dyn_this_cap ? scr_dyn_this_cap * 2 : 8;
     ScrDynThisEnt *s = realloc(scr_dyn_this_stack, cap * sizeof *s);
     if (!s) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     scr_dyn_this_stack = s;
     scr_dyn_this_cap = cap;
@@ -526,8 +523,7 @@ void scr_dyn_this_push_dyn(const ScrDyn *v) {
 
 void scr_dyn_this_pop(void) {
   if (scr_dyn_this_n == 0) {
-    fputs("scriptc: internal error: receiver stack underflow\n", stderr);
-    abort();
+    scr_trap("scriptc: internal error: receiver stack underflow\n");
   }
   ScrDynThisEnt *e = &scr_dyn_this_stack[--scr_dyn_this_n];
   if (e->dv) scr_dyn_release(e->dv);
@@ -763,13 +759,12 @@ ScrDyn *scr_dyn_from_error(const ScrError *e) {
     scr_errdyn_cap = scr_errdyn_cap ? scr_errdyn_cap * 2 : 8;
     scr_errdyn_cache = realloc(scr_errdyn_cache, scr_errdyn_cap * sizeof *scr_errdyn_cache);
     if (!scr_errdyn_cache) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
   }
   if (!scr_errdyn_teardown_registered) {
     scr_errdyn_teardown_registered = true;
-    atexit(scr_errdyn_teardown);
+    scr_atexit(scr_errdyn_teardown);
   }
   scr_errdyn_cache[scr_errdyn_n].err = scr_error_retain((ScrError *)e);
   scr_errdyn_cache[scr_errdyn_n].dyn = scr_dyn_retain(d);
@@ -824,13 +819,12 @@ void scr_errdyn_put(ScrError *e, ScrDyn *d) {
     scr_errdyn_cap = scr_errdyn_cap ? scr_errdyn_cap * 2 : 8;
     scr_errdyn_cache = realloc(scr_errdyn_cache, scr_errdyn_cap * sizeof *scr_errdyn_cache);
     if (!scr_errdyn_cache) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
   }
   if (!scr_errdyn_teardown_registered) {
     scr_errdyn_teardown_registered = true;
-    atexit(scr_errdyn_teardown);
+    scr_atexit(scr_errdyn_teardown);
   }
   scr_errdyn_cache[scr_errdyn_n].err = scr_error_retain(e);
   scr_errdyn_cache[scr_errdyn_n].dyn = scr_dyn_retain(d);
@@ -1035,8 +1029,7 @@ void scr_jb_put_dyn(ScrJsonBuf *b, const ScrDyn *d) {
     return;
   }
   }
-  fputs("scriptc: internal error: invalid dyn kind\n", stderr);
-  abort();
+  scr_trap("scriptc: internal error: invalid dyn kind\n");
 }
 
 /* ── dynCheck failure path ─────────────────────────────────────────────── */
@@ -1750,8 +1743,7 @@ static ScrDyn *scr_sc_clone(const ScrDyn *v, const ScrScParent *up) {
     size_t len = what->len + sizeof suffix - 1;
     char *msg = malloc(len + 1);
     if (!msg) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     memcpy(msg, what->data, what->len);
     memcpy(msg + what->len, suffix, sizeof suffix);
@@ -1860,8 +1852,7 @@ static ScrDyn *scr_dyn_objwalk(const ScrDyn *v, ScrObjWalk mode) {
     bool *is_index = malloc(n ? n * sizeof *is_index : 1);
     double *idx = malloc(n ? n * sizeof *idx : 1);
     if (!is_index || !idx) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     size_t index_count = 0;
     for (size_t i = 0; i < n; i++) {
diff --git a/packages/runtime/src/scr_lib.c b/packages/runtime/src/scr_lib.c
index 626de9a5b..7b2d4164a 100644
--- a/packages/runtime/src/scr_lib.c
+++ b/packages/runtime/src/scr_lib.c
@@ -132,6 +132,14 @@ void scr_lib_init(int argc, char **argv) {
   atexit(scr_lib_cleanup);
 }
 
+#ifdef SCR_CORE
+/* Core builds never call scr_lib_init (a core has no argv and registers no
+ * atexit handlers); the interned process values above still intern lazily
+ * on first read, so the core reset seam releases them here instead —
+ * scr_core_reset (scr_core.c) calls this every session reset. */
+void scr_lib_core_cleanup(void) { scr_lib_cleanup(); }
+#endif
+
 /* Raw argv accessors for the island's process shim (scr_island.c): the
  * island's process.argv must match the static world's ["scriptc",
  * argv[0], ...] shape exactly, so both build from the same stash. */
@@ -261,8 +269,7 @@ ScrStr *scr_env_get(const ScrStr *name) {
   if (need == 0) return NULL; /* absent (an empty value still needs its NUL) */
   char *buf = malloc(need);
   if (!buf) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   DWORD got = GetEnvironmentVariableA(name->data, buf, need);
   ScrStr *s = scr_str_new(buf, got);
@@ -553,8 +560,7 @@ bool scr_process_kill_named(double pid, const ScrStr *signal) {
     size_t cap = 16 + signal->len + 1;
     char *msg = malloc(cap);
     if (!msg) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     int len = snprintf(msg, cap, "Unknown signal: %s", signal->data);
     scr_throw_error_msg(SCR_ERR_TYPE, msg, (size_t)len);
@@ -567,8 +573,7 @@ bool scr_process_kill_named(double pid, const ScrStr *signal) {
 ScrStr *scr_process_cwd(void) {
   char buf[4096];
   if (!getcwd(buf, sizeof buf)) {
-    fputs("scriptc: process.cwd() failed\n", stderr);
-    abort();
+    scr_trap("scriptc: process.cwd() failed\n");
   }
   return scr_str_new(buf, strlen(buf));
 }
@@ -612,16 +617,14 @@ bool scr_proc_stream_write(double fd, const ScrStr *data) {
 ScrStr *scr_os_homedir(void) {
   const char *home = getenv("USERPROFILE");
   if (home && home[0] != '\0') return scr_str_new(home, strlen(home));
-  fputs("scriptc: os.homedir() failed\n", stderr);
-  abort();
+  scr_trap("scriptc: os.homedir() failed\n");
 }
 
 ScrStr *scr_os_user_name(void) {
   char buf[UNLEN + 1];
   DWORD n = sizeof buf;
   if (!GetUserNameA(buf, &n) || n == 0) {
-    fputs("scriptc: os.userInfo() failed\n", stderr);
-    abort();
+    scr_trap("scriptc: os.userInfo() failed\n");
   }
   return scr_str_new(buf, n - 1); /* n counts the NUL */
 }
@@ -648,8 +651,7 @@ ScrStr *scr_os_release(void) {
   RtlGetVersionFn fn =
       ntdll ? (RtlGetVersionFn)(void *)GetProcAddress(ntdll, "RtlGetVersion") : NULL;
   if (fn == NULL || fn(&info) != 0) {
-    fputs("scriptc: os.release() failed\n", stderr);
-    abort();
+    scr_trap("scriptc: os.release() failed\n");
   }
   char buf[64];
   int len = snprintf(buf, sizeof buf, "%lu.%lu.%lu", (unsigned long)info.dwMajorVersion,
@@ -676,8 +678,7 @@ ScrStr *scr_os_tmpdir(void) {
   char buf[MAX_PATH + 2];
   DWORD n = GetTempPathA(sizeof buf, buf);
   if (n == 0 || n >= sizeof buf) {
-    fputs("scriptc: os.tmpdir() failed\n", stderr);
-    abort();
+    scr_trap("scriptc: os.tmpdir() failed\n");
   }
   size_t len = n;
   if (len > 1 && (buf[len - 1] == '\\' || buf[len - 1] == '/')) len--;
@@ -693,8 +694,7 @@ ScrStr *scr_os_homedir(void) {
   struct passwd *result = NULL;
   char buf[8192];
   if (getpwuid_r(getuid(), &pw, buf, sizeof buf, &result) != 0 || !result || !result->pw_dir) {
-    fputs("scriptc: os.homedir() failed\n", stderr);
-    abort();
+    scr_trap("scriptc: os.homedir() failed\n");
   }
   return scr_str_new(result->pw_dir, strlen(result->pw_dir));
 }
@@ -706,8 +706,7 @@ ScrStr *scr_os_homedir(void) {
 static const struct passwd *scr_os_passwd(char *buf, size_t cap, struct passwd *pw) {
   struct passwd *result = NULL;
   if (getpwuid_r(getuid(), pw, buf, cap, &result) != 0 || !result) {
-    fputs("scriptc: os.userInfo() failed\n", stderr);
-    abort();
+    scr_trap("scriptc: os.userInfo() failed\n");
   }
   return result;
 }
@@ -740,8 +739,7 @@ ScrStr *scr_os_release(void) {
   /* uname(2)'s release field — Node's uv_os_uname()-backed answer. */
   struct utsname u;
   if (uname(&u) != 0) {
-    fputs("scriptc: os.release() failed\n", stderr);
-    abort();
+    scr_trap("scriptc: os.release() failed\n");
   }
   return scr_str_new(u.release, strlen(u.release));
 }
@@ -750,8 +748,7 @@ ScrStr *scr_os_type(void) {
   /* uname(2)'s sysname field ("Darwin", "Linux") — Node's os.type(). */
   struct utsname u;
   if (uname(&u) != 0) {
-    fputs("scriptc: os.type() failed\n", stderr);
-    abort();
+    scr_trap("scriptc: os.type() failed\n");
   }
   return scr_str_new(u.sysname, strlen(u.sysname));
 }
@@ -824,20 +821,20 @@ struct ScrIfaddrs {
  * stance. */
 ScrIfaddrs *scr_os_ifaddrs(void) {
   ScrIfaddrs *s = calloc(1, sizeof *s);
-  if (!s) abort();
+  if (!s) scr_trap("scriptc: out of memory\n");
   ULONG flags = GAA_FLAG_INCLUDE_PREFIX | GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST |
                 GAA_FLAG_SKIP_DNS_SERVER;
   ULONG size = 16 * 1024;
   IP_ADAPTER_ADDRESSES *adapters = NULL;
   for (int tries = 0; tries < 4; tries++) {
     adapters = realloc(adapters, size);
-    if (!adapters) abort();
+    if (!adapters) scr_trap("scriptc: out of memory\n");
     ULONG rc = GetAdaptersAddresses(AF_UNSPEC, flags, NULL, adapters, &size);
     if (rc == ERROR_SUCCESS) break;
     if (rc != ERROR_BUFFER_OVERFLOW) {
       free(adapters);
       s->rows = calloc(1, sizeof *s->rows);
-      if (!s->rows) abort();
+      if (!s->rows) scr_trap("scriptc: out of memory\n");
       return s; /* empty snapshot */
     }
   }
@@ -850,7 +847,7 @@ ScrIfaddrs *scr_os_ifaddrs(void) {
     }
   }
   s->rows = calloc(count ? count : 1, sizeof *s->rows);
-  if (!s->rows) abort();
+  if (!s->rows) scr_trap("scriptc: out of memory\n");
   for (IP_ADAPTER_ADDRESSES *a = adapters; a != NULL; a = a->Next) {
     if (a->OperStatus != IfOperStatusUp || a->FirstUnicastAddress == NULL) continue;
     char name[64] = "";
@@ -934,7 +931,7 @@ static int scr_netmask_prefix(const unsigned char *bytes, size_t len) {
 
 ScrIfaddrs *scr_os_ifaddrs(void) {
   ScrIfaddrs *s = calloc(1, sizeof *s);
-  if (!s) abort();
+  if (!s) scr_trap("scriptc: out of memory\n");
   struct ifaddrs *addrs = NULL;
   if (getifaddrs(&addrs) != 0) return s;
   size_t count = 0;
@@ -942,7 +939,7 @@ ScrIfaddrs *scr_os_ifaddrs(void) {
     if (scr_ifaddr_row_ok(ent)) count++;
   }
   s->rows = calloc(count ? count : 1, sizeof *s->rows);
-  if (!s->rows) abort();
+  if (!s->rows) scr_trap("scriptc: out of memory\n");
   for (struct ifaddrs *ent = addrs; ent != NULL; ent = ent->ifa_next) {
     if (!scr_ifaddr_row_ok(ent)) continue;
     ScrIfaddrRow *row = &s->rows[s->n++];
@@ -1409,8 +1406,7 @@ void scr_fs_throw(int e, const char *op, const ScrStr *path) {
   size_t cap = strlen(name) + strlen(text) + strlen(op) + strlen(shown) + 8;
   char *msg = malloc(cap);
   if (!msg) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   int len = snprintf(msg, cap, "%s: %s, %s '%s'", name, text, op, shown);
   /* A real Error instance (name "Error", message = Node's text) — what a
@@ -1433,16 +1429,14 @@ ScrStr *scr_fs_read_file(ScrStr *path) {
   size_t cap = 4096, len = 0;
   char *buf = malloc(cap);
   if (!buf) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   for (;;) {
     if (cap - len < 2048) {
       cap *= 2;
       char *grown = realloc(buf, cap);
       if (!grown) {
-        fputs("scriptc: out of memory\n", stderr);
-        abort();
+        scr_trap("scriptc: out of memory\n");
       }
       buf = grown;
     }
@@ -1688,8 +1682,7 @@ static void scr_fs_throw2(int e, const char *op, const ScrStr *src, const ScrStr
   size_t cap = strlen(name) + strlen(text) + strlen(op) + strlen(shown_src) + strlen(shown_dest) + 16;
   char *msg = malloc(cap);
   if (!msg) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   int len = snprintf(msg, cap, "%s: %s, %s '%s' -> '%s'", name, text, op, shown_src, shown_dest);
   scr_throw_error_msg_code(SCR_ERR_ERROR, msg, (size_t)len, name);
@@ -1846,8 +1839,7 @@ static void scr_mkdir_rec(char *path, size_t len, mode_t mode) {
 void scr_fs_mkdir_recursive(ScrStr *path) {
   char *buf = malloc(path->len + 1);
   if (!buf) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   memcpy(buf, path->data, path->len + 1); /* ScrStr data is NUL-terminated */
   scr_mkdir_rec(buf, path->len, 0777);
@@ -1859,8 +1851,7 @@ void scr_fs_mkdir_recursive(ScrStr *path) {
 void scr_fs_mkdir_recursive_mode(ScrStr *path, double mode) {
   char *buf = malloc(path->len + 1);
   if (!buf) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   memcpy(buf, path->data, path->len + 1);
   scr_mkdir_rec(buf, path->len, (mode_t)mode);
@@ -1907,8 +1898,7 @@ static void scr_rm_tree_e(const char *path, size_t len, ScrRmFail *f) {
     size_t namelen = strlen(ent->d_name);
     char *child = malloc(len + 1 + namelen + 1);
     if (!child) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     memcpy(child, path, len);
     child[len] = '/';
@@ -2011,8 +2001,7 @@ static char *scr_win_mkdtemp(char *tmpl) {
 ScrStr *scr_fs_mkdtemp(ScrStr *prefix) {
   char *tmpl = malloc(prefix->len + 7);
   if (!tmpl) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   memcpy(tmpl, prefix->data, prefix->len);
   memcpy(tmpl + prefix->len, "XXXXXX", 7);
@@ -2059,16 +2048,14 @@ static char *scr_read_fd_all(double fd, size_t *out_len) {
   size_t cap = 4096, len = 0;
   char *buf = malloc(cap);
   if (!buf) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   for (;;) {
     if (cap - len < 2048) {
       cap *= 2;
       char *grown = realloc(buf, cap);
       if (!grown) {
-        fputs("scriptc: out of memory\n", stderr);
-        abort();
+        scr_trap("scriptc: out of memory\n");
       }
       buf = grown;
     }
@@ -2276,8 +2263,7 @@ double scr_stats_mtime_ms(ScrStats *s) { return s->mtime_ms; }
 static ScrStats *scr_stats_of(const struct stat *st) {
   ScrStats *s = malloc(sizeof(ScrStats));
   if (!s) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   s->rc = 1;
   s->is_file = S_ISREG(st->st_mode);
@@ -2374,16 +2360,14 @@ ScrScandir *scr_fs_scandir(ScrStr *path) {
   }
   ScrScandir *s = malloc(sizeof *s);
   if (!s) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   s->len = 0;
   s->cap = 8;
   s->names = malloc(s->cap * sizeof *s->names);
   s->kinds = malloc(s->cap);
   if (!s->names || !s->kinds) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   const struct dirent *ent;
   while ((ent = readdir(d)) != NULL) {
@@ -2424,8 +2408,7 @@ ScrScandir *scr_fs_scandir(ScrStr *path) {
       s->names = realloc(s->names, s->cap * sizeof *s->names);
       s->kinds = realloc(s->kinds, s->cap);
       if (!s->names || !s->kinds) {
-        fputs("scriptc: out of memory\n", stderr);
-        abort();
+        scr_trap("scriptc: out of memory\n");
       }
     }
     s->names[s->len] = scr_str_new(ent->d_name, strlen(ent->d_name));
@@ -2535,8 +2518,7 @@ ScrStr *scr_crypto_random_string(double n, ScrStr *enc) {
   size_t size = (size_t)n;
   unsigned char *bytes = malloc(size ? size : 1);
   if (!bytes) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   arc4random_buf(bytes, size);
   ScrStr *out;
@@ -2544,8 +2526,7 @@ ScrStr *scr_crypto_random_string(double n, ScrStr *enc) {
     static const char hex[] = "0123456789abcdef";
     char *buf = malloc(size * 2 + 1);
     if (!buf) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     for (size_t i = 0; i < size; i++) {
       buf[i * 2] = hex[bytes[i] >> 4];
@@ -2559,8 +2540,7 @@ ScrStr *scr_crypto_random_string(double n, ScrStr *enc) {
     size_t outlen = (size + 2) / 3 * 4;
     char *buf = malloc(outlen + 1);
     if (!buf) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     size_t o = 0;
     for (size_t i = 0; i < size; i += 3) {
@@ -2899,8 +2879,7 @@ static bool scr_x509_der(const uint8_t *in, size_t n, const uint8_t **der, size_
     }
     uint8_t *out = malloc(((size_t)(stop - b) / 4 + 1) * 3 + 3);
     if (!out) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     size_t o = 0;
     unsigned acc = 0;
@@ -3116,8 +3095,7 @@ static uint32_t scr_to_uint32(double d);
 static ScrStr *scr_str_from_units(size_t n, uint32_t (*unit)(void *, size_t), void *src) {
   char *out = malloc(n * 3 + 1); /* worst case: 3 bytes per UTF-16 unit */
   if (!out) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   size_t o = 0;
   for (size_t i = 0; i < n; i++) {
diff --git a/packages/runtime/src/scr_map.c b/packages/runtime/src/scr_map.c
index f077ed9ed..0922e11fe 100644
--- a/packages/runtime/src/scr_map.c
+++ b/packages/runtime/src/scr_map.c
@@ -31,8 +31,7 @@ long scr_map_live_count(void) { return scr_live_maps; }
 #define SCR_MAP_EMPTY SIZE_MAX
 
 static void scr_map_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* ── key normalization + hashing (SameValueZero) ───────────────────────
@@ -462,8 +461,7 @@ bool scr_map_iter_live(const ScrMap *m, double i) {
 
 static const ScrMapEntry *scr_map_iter_at(const ScrMap *m, double i) {
   if (!(i >= 0) || i >= (double)m->nentries || !m->entries[(size_t)i].live) {
-    fputs("scriptc: internal error: map iteration index out of range\n", stderr);
-    abort();
+    scr_trap("scriptc: internal error: map iteration index out of range\n");
   }
   return &m->entries[(size_t)i];
 }
diff --git a/packages/runtime/src/scr_path.c b/packages/runtime/src/scr_path.c
index 4050e007f..0a21f3eb3 100644
--- a/packages/runtime/src/scr_path.c
+++ b/packages/runtime/src/scr_path.c
@@ -37,8 +37,7 @@ static void pb_init(PathBuf *b) {
   b->len = 0;
   b->data = malloc(b->cap);
   if (!b->data) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
 }
 
@@ -47,8 +46,7 @@ static void pb_reserve(PathBuf *b, size_t extra) {
   while (b->len + extra > b->cap) b->cap *= 2;
   char *grown = realloc(b->data, b->cap);
   if (!grown) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   b->data = grown;
 }
@@ -226,8 +224,7 @@ ScrStr *scr_path_join(ScrArr *parts) {
 static void scr_path_cwd(PathBuf *out) {
   char buf[4096];
   if (!getcwd(buf, sizeof buf)) {
-    fputs("scriptc: path.resolve: getcwd failed\n", stderr);
-    abort();
+    scr_trap("scriptc: path.resolve: getcwd failed\n");
   }
   pb_append(out, buf, strlen(buf));
 }
@@ -984,8 +981,7 @@ ScrStr *scr_path_win32_relative(ScrStr *from, ScrStr *to) {
   char *flow = malloc(rfrom->len ? rfrom->len : 1);
   char *tlow = malloc(rto->len ? rto->len : 1);
   if (!flow || !tlow) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   for (size_t k = 0; k < rfrom->len; k++) flow[k] = scr_path_w32_lower(rfrom->data[k]);
   for (size_t k = 0; k < rto->len; k++) tlow[k] = scr_path_w32_lower(rto->data[k]);
diff --git a/packages/runtime/src/scr_regex.c b/packages/runtime/src/scr_regex.c
index f66287869..b2c719e50 100644
--- a/packages/runtime/src/scr_regex.c
+++ b/packages/runtime/src/scr_regex.c
@@ -37,8 +37,7 @@
 #include "libregexp.h"
 
 static void scr_regex_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* ── libregexp host hooks ─────────────────────────────────────────────
@@ -102,7 +101,7 @@ static void scr_note_compiled(ScrRegex *re) {
     scr_compiled = realloc(scr_compiled, scr_compiled_cap * sizeof *scr_compiled);
     if (!scr_compiled) scr_regex_oom();
   }
-  if (scr_compiled_len == 0) atexit(scr_regex_free_bytecodes);
+  if (scr_compiled_len == 0) scr_atexit(scr_regex_free_bytecodes);
   scr_compiled[scr_compiled_len++] = re;
 }
 
@@ -119,9 +118,8 @@ static int scr_lre_flags(const ScrStr *flags) {
       case 'u': mask |= LRE_FLAG_UNICODE; break;
       case 'y': mask |= LRE_FLAG_STICKY; break;
       default:
-        fprintf(stderr, "scriptc: internal error: unexpected regex flag '%c'\n",
-                flags->data[i]);
-        abort();
+        scr_trap_fmt("scriptc: internal error: unexpected regex flag '%c'\n",
+                     flags->data[i]);
     }
   }
   return mask;
@@ -197,9 +195,8 @@ static uint8_t *scr_regex_bc(ScrRegex *re) {
      * tsc's parser has already caught plain syntax errors, so this is
      * rare). */
     fflush(stdout);
-    fprintf(stderr, "scriptc: SyntaxError: Invalid regular expression: /%s/%s: %s\n",
-            re->source->data, re->flags->data, error_msg);
-    abort();
+    scr_trap_fmt("scriptc: SyntaxError: Invalid regular expression: /%s/%s: %s\n",
+                 re->source->data, re->flags->data, error_msg);
   }
   re->bc = bc;
   scr_note_compiled(re);
@@ -315,8 +312,7 @@ static int scr_exec(uint8_t **capture, const uint8_t *bc, const uint16_t *u,
   int rc = lre_exec(capture, bc, (const uint8_t *)u, index, len, 1, lre_opaque());
   if (rc < 0) {
     fflush(stdout);
-    fputs("scriptc: regular expression execution failed\n", stderr);
-    abort();
+    scr_trap("scriptc: regular expression execution failed\n");
   }
   return rc;
 }
@@ -351,11 +347,9 @@ bool scr_regex_test(ScrRegex *re, ScrStr *s) {
      * iteration this slice does not model (the frontend rejects the sites
      * it can see; values that flow through variables land here). */
     fflush(stdout);
-    fprintf(stderr,
-            "scriptc: test() on a regex with the 'g' or 'y' flag is not "
-            "supported (stateful lastIndex); drop the flag, or use "
-            "replace/replaceAll/split\n");
-    abort();
+    scr_trap("scriptc: test() on a regex with the 'g' or 'y' flag is not "
+             "supported (stateful lastIndex); drop the flag, or use "
+             "replace/replaceAll/split\n");
   }
   int len;
   uint16_t *u = scr_to_utf16(s, &len);
@@ -379,11 +373,9 @@ ScrArr *scr_regex_match(ScrStr *s, ScrRegex *re) {
   uint8_t *bc = scr_regex_bc(re);
   if (lre_get_flags(bc) & (LRE_FLAG_GLOBAL | LRE_FLAG_STICKY)) {
     fflush(stdout);
-    fprintf(stderr,
-            "scriptc: match() on a regex with the 'g' or 'y' flag is not "
-            "supported (an every-match array is a different shape); drop the "
-            "flag, or use replace/replaceAll/split\n");
-    abort();
+    scr_trap("scriptc: match() on a regex with the 'g' or 'y' flag is not "
+             "supported (an every-match array is a different shape); drop the "
+             "flag, or use replace/replaceAll/split\n");
   }
   int len;
   uint16_t *u = scr_to_utf16(s, &len);
@@ -803,7 +795,7 @@ static bool scr_assert_regex_hits(ScrRegex *re, ScrStr *s) {
 static ScrStr *scr_assert_regex_render(ScrRegex *re) {
   size_t cap = re->source->len + re->flags->len + 2;
   char *buf = malloc(cap);
-  if (!buf) abort();
+  if (!buf) scr_trap("scriptc: out of memory\n");
   size_t n = 0;
   buf[n++] = '/';
   memcpy(buf + n, re->source->data, re->source->len);
@@ -831,7 +823,7 @@ static void scr_assert_regex_input_fail(bool negated, ScrRegex *re, ScrStr *inpu
   const char *mid = ". Input:\n\n";
   size_t cap = strlen(head) + rre->len + strlen(mid) + insp->len + 1;
   char *buf = malloc(cap);
-  if (!buf) abort();
+  if (!buf) scr_trap("scriptc: out of memory\n");
   size_t n = 0;
   memcpy(buf + n, head, strlen(head));
   n += strlen(head);
@@ -924,8 +916,7 @@ ScrRegex *scr_regex_new(ScrStr *pattern, ScrStr *flags) {
   }
   ScrRegex *re = calloc(1, sizeof *re);
   if (!re) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   re->rc = 1;
   re->source = pattern->len > 0 ? scr_str_retain(pattern) : scr_str_new("(?:)", 4);
diff --git a/packages/runtime/src/scr_runtime.h b/packages/runtime/src/scr_runtime.h
index 6df8b8afd..f36d85dcf 100644
--- a/packages/runtime/src/scr_runtime.h
+++ b/packages/runtime/src/scr_runtime.h
@@ -39,6 +39,81 @@ char *strcasestr(const char *hay, const char *needle);
  * flush-at-exit, RC audit registration (when built with -DSCR_RC_AUDIT). */
 void scr_init(void);
 
+/* ── the trap funnel (scr_console.c; scr_core.c under -DSCR_CORE) ──────
+ * Every unrecoverable runtime trap — OOM, semantic range traps, internal-
+ * invariant failures — funnels through this pair instead of open-coded
+ * fputs/fprintf + abort. Executable builds expand to exactly the historical
+ * behavior (the message's bytes on stderr, then abort — the default lane
+ * must not change by a byte). Core builds (-DSCR_CORE) route the message to
+ * the host-registered panic sink and abort only as the last resort: before
+ * registration, or if the sink returns (the ruled host-contract violation —
+ * a conforming sink longjmps to a host frame BELOW the entry, never back
+ * into core frames). Messages keep their trailing newline in both lanes so
+ * the funnel is a pure indirection over identical bytes. */
+_Noreturn void scr_trap(const char *msg);
+_Noreturn void scr_trap_fmt(const char *fmt, ...);
+
+/* ── core (library) mode (scr_core.c, linked only into core artifacts) ──
+ * A core artifact has no main, no event loop, no signal handlers, no
+ * atexit registrations, and never touches host stdio modes or buffering:
+ * initialization runs inside the profile-named init entry (re-runnable
+ * deterministically), traps route to the sink above, and buffer-class
+ * results live in a core-owned result arena. Everything here compiles only
+ * under -DSCR_CORE; executable builds never contain it. */
+#ifdef SCR_CORE
+typedef struct ScrStr ScrStr;     /* full definitions below (C11 repeat) */
+typedef struct ScrBytes ScrBytes;
+/* The host's panic sink: msg is UTF-8, valid only for the duration of the
+ * call; address is the trap site's return address (0 when the toolchain
+ * cannot supply one); ctx is the registration's opaque pointer. The sink
+ * must not call back into any core entry and must not unwind or longjmp
+ * back into core frames. */
+typedef void (*ScrCoreSinkFn)(void *ctx, const uint8_t *msg, size_t msg_len,
+                              uint64_t address);
+void scr_core_set_sink(ScrCoreSinkFn fn, void *ctx); /* latest wins */
+
+/* Entry prologue: aborts deterministically when the core is poisoned (a
+ * trap already fired — no profile entry may run again; recovery is process
+ * restart). reset_arena additionally drops the result arena (the
+ * auto-reset posture, and the reset/collect entries' shared body). */
+void scr_core_entry(bool reset_arena);
+void scr_core_arena_reset(void);
+/* The mode-provided collect entry's body: arena reset + a full cycle
+ * collection (snapshot-invariant by construction — collection frees only
+ * unreachable cycles). */
+void scr_core_collect(void);
+
+/* Full session reset, called by the generated init entry AFTER the program
+ * TU released and zeroed its globals: pending-exception clear, arena
+ * reset, the reset registry's drains (the units' repointed atexit halves),
+ * the library's interned process values, a cycle collection, and — under
+ * SCR_RC_AUDIT — the zero-live-heap assertion (a failure is a trap through
+ * the sink, never _Exit). */
+void scr_core_reset(void);
+/* Where a unit would atexit() a lazy teardown, core builds register it
+ * here instead (called on every scr_core_reset, registered once). */
+void scr_core_register_reset(void (*fn)(void));
+/* An escaped exception at an entry boundary: renders the same "Uncaught
+ * ..." text the executable epilogue prints, releases the payload, and
+ * routes the text through the trap funnel. No-op when nothing is pending.
+ * Defined in scr_exception.c (it owns the cell). */
+void scr_core_check_exc(void);
+
+/* Marshalling helpers the generated wrappers call (both emissions share
+ * these bodies, which is how the two lanes stay identical by
+ * construction). Inbound is borrowed-and-copied; outbound values MOVE into
+ * the result arena and stay valid until the next arena reset. String
+ * results are NUL-terminated after *out_len bytes (ScrStr's layout). */
+ScrStr *scr_core_str_in(const uint8_t *p, size_t len);   /* +1 */
+ScrBytes *scr_core_bytes_in(const uint8_t *p, size_t len); /* +1, u8 */
+void scr_core_str_out(ScrStr *s, const uint8_t **out, size_t *out_len);
+void scr_core_bytes_out(ScrBytes *b, const uint8_t **out, size_t *out_len);
+
+#define scr_atexit(fn) scr_core_register_reset(fn)
+#else
+#define scr_atexit(fn) atexit(fn)
+#endif /* SCR_CORE */
+
 /* ── cycle collection (scr_cycle.c) ───────────────────────────────────
  * Reference counting alone cannot free cycles, so every object that can
  * participate in one — capture boxes, heap closures, unions, promises, and
diff --git a/packages/runtime/src/scr_string.c b/packages/runtime/src/scr_string.c
index 982ceee9c..11a399062 100644
--- a/packages/runtime/src/scr_string.c
+++ b/packages/runtime/src/scr_string.c
@@ -15,8 +15,7 @@ long scr_str_live_count(void) { return scr_live_strings; }
 #endif
 
 static void scr_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 /* ── UTF-16 index cache ───────────────────────────────────────────────
@@ -519,8 +518,7 @@ ScrStr *scr_str_slice(ScrStr *s, double start, double end) {
 ScrStr *scr_str_repeat(ScrStr *s, double count) {
   double n = scr_to_integer_or_infinity(count);
   if (n < 0 || (isinf(n) && n > 0)) {
-    fputs("scriptc: RangeError: Invalid count value\n", stderr);
-    abort();
+    scr_trap("scriptc: RangeError: Invalid count value\n");
   }
   if (n == 0 || s->len == 0) return scr_str_empty();
   /* n is a finite non-negative integer here. Reject sizes malloc could not
diff --git a/packages/runtime/src/scr_symbol.c b/packages/runtime/src/scr_symbol.c
index f976cf255..cd2a7a7cf 100644
--- a/packages/runtime/src/scr_symbol.c
+++ b/packages/runtime/src/scr_symbol.c
@@ -44,8 +44,7 @@ void scr_sym_release_v(void *p) { scr_sym_release(p); }
 ScrSym *scr_sym_new(ScrStr *desc) {
   ScrSym *s = malloc(sizeof(ScrSym));
   if (!s) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   s->rc = 1;
   s->desc = desc ? scr_str_retain(desc) : NULL;
@@ -75,7 +74,7 @@ ScrSym *scr_sym_for(ScrStr *key) {
   /* First request for this key: a fresh symbol whose description IS the
    * key (the spec's Symbol.for behavior), chained into the registry with
    * the registry's own reference. */
-  if (!g_sym_registry) atexit(scr_sym_registry_cleanup);
+  if (!g_sym_registry) scr_atexit(scr_sym_registry_cleanup);
   ScrSym *s = scr_sym_new(key);
   s->reg_key = scr_str_retain(key);
   s->reg_next = g_sym_registry;
diff --git a/packages/runtime/src/scr_url.c b/packages/runtime/src/scr_url.c
index 705108ec7..777440518 100644
--- a/packages/runtime/src/scr_url.c
+++ b/packages/runtime/src/scr_url.c
@@ -69,8 +69,7 @@ static void ub_init(UrlBuf *b) {
   b->len = 0;
   b->data = malloc(b->cap);
   if (!b->data) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
 }
 
@@ -79,8 +78,7 @@ static void ub_append(UrlBuf *b, const char *bytes, size_t n) {
     while (b->len + n > b->cap) b->cap *= 2;
     char *grown = realloc(b->data, b->cap);
     if (!grown) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     b->data = grown;
   }
@@ -182,8 +180,7 @@ static ScrStr *parse_rooted_path(const char *raw, size_t len, bool special) {
   size_t seg_starts_cap = 8, seg_count = 0;
   size_t *seg_starts = malloc(seg_starts_cap * sizeof(size_t));
   if (!seg_starts) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   size_t i = 0;
   /* One leading separator opens the first segment (rooted). */
@@ -206,7 +203,7 @@ static ScrStr *parse_rooted_path(const char *raw, size_t len, bool special) {
         if (seg_count == seg_starts_cap) {
           seg_starts_cap *= 2;
           seg_starts = realloc(seg_starts, seg_starts_cap * sizeof(size_t));
-          if (!seg_starts) abort();
+          if (!seg_starts) scr_trap("scriptc: out of memory\n");
         }
         seg_starts[seg_count++] = out.len;
       }
@@ -215,7 +212,7 @@ static ScrStr *parse_rooted_path(const char *raw, size_t len, bool special) {
         if (seg_count == seg_starts_cap) {
           seg_starts_cap *= 2;
           seg_starts = realloc(seg_starts, seg_starts_cap * sizeof(size_t));
-          if (!seg_starts) abort();
+          if (!seg_starts) scr_trap("scriptc: out of memory\n");
         }
         seg_starts[seg_count++] = out.len;
       }
@@ -224,8 +221,7 @@ static ScrStr *parse_rooted_path(const char *raw, size_t len, bool special) {
         seg_starts_cap *= 2;
         seg_starts = realloc(seg_starts, seg_starts_cap * sizeof(size_t));
         if (!seg_starts) {
-          fputs("scriptc: out of memory\n", stderr);
-          abort();
+          scr_trap("scriptc: out of memory\n");
         }
       }
       seg_starts[seg_count++] = out.len;
@@ -355,8 +351,7 @@ ScrUrl *scr_url_new(ScrStr *input) {
   while (e > b && (unsigned char)raw[e - 1] <= 0x20) e--;
   char *buf = malloc(e - b + 1);
   if (!buf) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   size_t len = 0;
   for (size_t i = b; i < e; i++) {
@@ -526,8 +521,7 @@ ScrUrl *scr_url_new(ScrStr *input) {
 
   ScrUrl *u = malloc(sizeof(ScrUrl));
   if (!u) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   u->rc = 1;
   u->scheme = scheme_str;
@@ -738,8 +732,7 @@ ScrStr *scr_url_str_to_path(ScrStr *input) {
 static ScrUrl *scr_url_new_file(ScrStr *host, ScrStr *encoded_path) {
   ScrUrl *u = malloc(sizeof(ScrUrl));
   if (!u) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   u->rc = 1;
   u->scheme = scr_str_new("file", 4);
diff --git a/packages/runtime/src/scr_url_params.c b/packages/runtime/src/scr_url_params.c
index ee3e42a21..fd3f5da97 100644
--- a/packages/runtime/src/scr_url_params.c
+++ b/packages/runtime/src/scr_url_params.c
@@ -26,8 +26,7 @@ static void ub_init(UrlBuf *b) {
   b->len = 0;
   b->data = malloc(b->cap);
   if (!b->data) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
 }
 
@@ -36,8 +35,7 @@ static void ub_append(UrlBuf *b, const char *bytes, size_t n) {
     while (b->len + n > b->cap) b->cap *= 2;
     char *grown = realloc(b->data, b->cap);
     if (!grown) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     b->data = grown;
   }
@@ -94,8 +92,7 @@ struct ScrSearchParams {
 static ScrSearchParams *sp_alloc(void) {
   ScrSearchParams *sp = malloc(sizeof(ScrSearchParams));
   if (!sp) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   sp->rc = 1;
   sp->len = 0;
@@ -103,8 +100,7 @@ static ScrSearchParams *sp_alloc(void) {
   sp->names = malloc(sp->cap * sizeof(ScrStr *));
   sp->vals = malloc(sp->cap * sizeof(ScrStr *));
   if (!sp->names || !sp->vals) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   sp->owner = NULL;
   return sp;
@@ -142,8 +138,7 @@ static void sp_push(ScrSearchParams *sp, ScrStr *name, ScrStr *value) {
     ScrStr **gn = realloc(sp->names, sp->cap * sizeof(ScrStr *));
     ScrStr **gv = realloc(sp->vals, sp->cap * sizeof(ScrStr *));
     if (!gn || !gv) {
-      fputs("scriptc: out of memory\n", stderr);
-      abort();
+      scr_trap("scriptc: out of memory\n");
     }
     sp->names = gn;
     sp->vals = gv;
@@ -161,8 +156,7 @@ static ScrStr *sp_scrub_utf8(const char *in_c, size_t n) {
   const unsigned char *in = (const unsigned char *)in_c;
   char *out = malloc(n * 3 + 1);
   if (!out) {
-    fputs("scriptc: out of memory\n", stderr);
-    abort();
+    scr_trap("scriptc: out of memory\n");
   }
   size_t o = 0;
   uint32_t cp = 0;
diff --git a/packages/runtime/src/scr_zlib.c b/packages/runtime/src/scr_zlib.c
index a98f7127b..19fafbbe3 100644
--- a/packages/runtime/src/scr_zlib.c
+++ b/packages/runtime/src/scr_zlib.c
@@ -18,8 +18,7 @@
 #include <zlib.h>
 
 static void scr_zlib_oom(void) {
-  fputs("scriptc: out of memory\n", stderr);
-  abort();
+  scr_trap("scriptc: out of memory\n");
 }
 
 ScrBytes *scr_zlib_deflate(const ScrBytes *data) {