diff --git a/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/assert-throws-shared-expected.ts.json b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/assert-throws-shared-expected.ts.json
new file mode 100644
index 000000000..aeed90273
--- /dev/null
+++ b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/assert-throws-shared-expected.ts.json
@@ -0,0 +1,6 @@
+{
+ "order": [
+  "<repo>/tests/corpus/assert-throws-shared-expected.ts"
+ ],
+ "diags": []
+}
diff --git a/packages/runtime/src/scr_assert.c b/packages/runtime/src/scr_assert.c
index 6e9384f15..f21e2ba26 100644
--- a/packages/runtime/src/scr_assert.c
+++ b/packages/runtime/src/scr_assert.c
@@ -2425,18 +2425,29 @@ void scr_assert_loose_deep_result(bool equal, bool negated, ScrStr *msg, bool ha
 /* Node's expectsError over an error-INSTANCE expected (assert.throws/
  * rejects second argument): every key of the expected dyn error (the
  * %error marker skipped; name/message/code is the encoding's surface)
- * must deep-strict-equal the caught value's — extra ACTUAL keys are fine
- * (Node walks the expected's keys only). A mismatch fails through the
+ * must be in the caught value (own or inherited) and deep-strict-equal
+ * it — extra ACTUAL keys are fine (Node walks the expected's keys only). A mismatch fails through the
  * deep-equal report (a mismatched key implies the full comparison
  * differs, so the diff is honest); a non-object pair falls back to the
  * full deep comparison outright. */
+/* actual[key] where `key in actual` holds: an own property or one on the
+ * prototype chain (an error's name, and its message when it is not own,
+ * sit on the prototype). NULL when the key is absent. */
+static ScrDyn *scr_assert_dyn_key(const ScrDyn *actual, const char *key, size_t key_len) {
+  for (const ScrDyn *o = actual; o != NULL && o->kind == SCR_DYN_OBJ; o = o->prototype) {
+    ScrDyn *v = scr_dyn_obj_get(o, key, key_len);
+    if (v != NULL) return v;
+  }
+  return NULL;
+}
+
 void scr_assert_expects_err_dyn(ScrDyn *actual, ScrDyn *expected, ScrStr *msg, bool has_msg) {
   if (actual->kind == SCR_DYN_OBJ && expected->kind == SCR_DYN_OBJ) {
     bool ok = true;
     for (size_t i = 0; i < scr_dyn_obj_count(expected) && ok; i++) {
       ScrDynProp e = scr_dyn_obj_prop_at(expected, i);
       if (e.key_len == 6 && memcmp(e.key, "%error", 6) == 0) continue;
-      ScrDyn *av = scr_dyn_obj_get(actual, e.key, e.key_len);
+      ScrDyn *av = scr_assert_dyn_key(actual, e.key, e.key_len);
       if (av == NULL || !scr_assert_dyn_deep_eq(av, e.value)) ok = false;
     }
     if (ok) return;
diff --git a/tests/corpus/assert-throws-shared-expected.ts b/tests/corpus/assert-throws-shared-expected.ts
new file mode 100644
index 000000000..a81dbfb24
--- /dev/null
+++ b/tests/corpus/assert-throws-shared-expected.ts
@@ -0,0 +1,46 @@
+// assert.throws and assert.rejects with an expected object held in a
+// variable compare each of its keys with the thrown error's, own or
+// inherited: an error's name is on its prototype, so { name, message, code }
+// matches errors the runtime throws as well as errors the program throws.
+import assert from "node:assert";
+
+const invalidUrl = { code: "ERR_INVALID_URL", name: "TypeError", message: "Invalid URL" };
+const outOfRange = { code: "ERR_OUT_OF_RANGE", name: "RangeError" };
+const thrownType = { name: "TypeError", message: "bad input" };
+const wrongName = { name: "RangeError", message: "bad input" };
+
+function check(label: string, fn: () => void): void {
+  try {
+    fn();
+    console.log(label, "passed");
+  } catch (error) {
+    const e = error as NodeJS.ErrnoException;
+    console.log(label, "failed", e.name, e.code);
+  }
+}
+
+check("url", () => assert.throws(() => new URL("not a url"), invalidUrl));
+check("buffer", () => assert.throws(() => Buffer.alloc(-1), outOfRange));
+check("thrown", () =>
+  assert.throws(() => {
+    throw new TypeError("bad input");
+  }, thrownType),
+);
+check("mismatch", () =>
+  assert.throws(() => {
+    throw new TypeError("bad input");
+  }, wrongName),
+);
+
+async function main(): Promise<void> {
+  await assert.rejects(Promise.reject(new TypeError("bad input")), thrownType);
+  console.log("rejects passed");
+  try {
+    await assert.rejects(Promise.reject(new TypeError("bad input")), wrongName);
+    console.log("rejects mismatch passed");
+  } catch (error) {
+    console.log("rejects mismatch failed", (error as NodeJS.ErrnoException).code);
+  }
+}
+
+void main();