diff --git a/crates/perry-runtime/src/node_stream_readwrite.rs b/crates/perry-runtime/src/node_stream_readwrite.rs
index 8d41581e85..b2b2200a51 100644
--- a/crates/perry-runtime/src/node_stream_readwrite.rs
+++ b/crates/perry-runtime/src/node_stream_readwrite.rs
@@ -1442,6 +1442,22 @@ pub(super) fn maybe_emit_default_read_error(stream: f64) {
     destroy_stream(stream, readable_default_read_error());
 }
 
+/// Test helper: make `stream` behave like a manually-driven Readable that was
+/// constructed with a (no-op) `_read`. #2441 made a *bare* Readable (one with
+/// no `_read`) raise `ERR_METHOD_NOT_IMPLEMENTED` and self-destroy on the first
+/// read — which is Node-correct (Node requires a `_read`). Tests that drive a
+/// stream purely via `push()` clear that marker so they exercise their intended
+/// push/flow/end lifecycle without tripping the error, exactly as real code
+/// would by passing `{ read() {} }` to the constructor.
+#[cfg(test)]
+pub(crate) fn test_install_manual_read(stream: f64) {
+    set_hidden_value(
+        stream,
+        hidden_default_read_error_key(),
+        f64::from_bits(TAG_FALSE),
+    );
+}
+
 pub(super) fn is_single_chunk_value(value: f64) -> bool {
     let jsval = JSValue::from_bits(value.to_bits());
     if jsval.is_any_string() {
diff --git a/crates/perry-runtime/src/node_stream_state_tests.rs b/crates/perry-runtime/src/node_stream_state_tests.rs
index b30b4d49d1..4cc4fb0547 100644
--- a/crates/perry-runtime/src/node_stream_state_tests.rs
+++ b/crates/perry-runtime/src/node_stream_state_tests.rs
@@ -28,6 +28,7 @@ fn fresh_streams_expose_destroyed_false() {
 #[test]
 fn readable_lifecycle_flags_reflect_ended_state() {
     let stream = js_node_stream_readable_new(f64::from_bits(TAG_UNDEFINED));
+    test_install_manual_read(stream);
     let handle = raw_ptr_from_value(stream) as i64;
     let obj = raw_ptr_from_value(stream) as *const ObjectHeader;
 
diff --git a/crates/perry-runtime/src/node_stream_tests.rs b/crates/perry-runtime/src/node_stream_tests.rs
index 51fe815258..54b4aafa28 100644
--- a/crates/perry-runtime/src/node_stream_tests.rs
+++ b/crates/perry-runtime/src/node_stream_tests.rs
@@ -216,6 +216,7 @@ fn readable_set_encoding_emits_buffer_chunks_as_strings() {
     READABLE_DATA_STRING_FLAGS.with(|flags| flags.borrow_mut().clear());
 
     let stream = js_node_stream_readable_new(f64::from_bits(TAG_UNDEFINED));
+    test_install_manual_read(stream);
     let handle = raw_ptr_from_value(stream) as i64;
     js_node_stream_method_set_encoding(handle, string_value("base64"));
 
diff --git a/crates/perry-runtime/src/node_stream_tests_extra.rs b/crates/perry-runtime/src/node_stream_tests_extra.rs
index 6f8401a998..705602deac 100644
--- a/crates/perry-runtime/src/node_stream_tests_extra.rs
+++ b/crates/perry-runtime/src/node_stream_tests_extra.rs
@@ -315,6 +315,7 @@ fn pause_resume_track_readable_flowing_and_events() {
     STREAM_EVENT_ORDER.with(|events| events.borrow_mut().clear());
 
     let stream = js_node_stream_readable_new(f64::from_bits(TAG_UNDEFINED));
+    test_install_manual_read(stream);
     let handle = raw_ptr_from_value(stream) as i64;
     let obj = raw_ptr_from_value(stream) as *const ObjectHeader;
     let pause = js_object_get_field_by_name_f64(obj, hidden_key(b"pause"));
@@ -378,6 +379,7 @@ fn readable_push_emits_data_with_stream_this_and_deferred_end() {
     READABLE_END_COUNT.with(|count| *count.borrow_mut() = 0);
 
     let stream = js_node_stream_readable_new(f64::from_bits(TAG_UNDEFINED));
+    test_install_manual_read(stream);
     let handle = raw_ptr_from_value(stream) as i64;
 
     let data_closure = js_closure_alloc(capture_data_listener as *const u8, 1);
diff --git a/crates/perry-runtime/src/node_submodules/mod.rs b/crates/perry-runtime/src/node_submodules/mod.rs
index e314c10cee..d214b36a45 100644
--- a/crates/perry-runtime/src/node_submodules/mod.rs
+++ b/crates/perry-runtime/src/node_submodules/mod.rs
@@ -1233,6 +1233,7 @@ mod tests {
     #[test]
     fn stream_promises_finished_rejects_later_destroy_error() {
         let stream = crate::node_stream::js_node_stream_readable_new(undefined_value());
+        crate::node_stream::test_install_manual_read(stream);
         let promise_value = thunk_streamP_finished(std::ptr::null(), stream, undefined_value());
         let promise = promise_ptr(promise_value);
 
diff --git a/scripts/check_file_size.sh b/scripts/check_file_size.sh
index 7b61cf8291..a201e08556 100755
--- a/scripts/check_file_size.sh
+++ b/scripts/check_file_size.sh
@@ -102,6 +102,12 @@ crates/perry-runtime/src/object/native_module.rs
 # ObjectHeader) tipped it over. Splitting the two towers into sibling
 # modules is tracked under #1435.
 crates/perry-runtime/src/builtins/formatting.rs
+# WHATWG Streams (ReadableStream/WritableStream/TransformStream + reader/
+# writer/controller dispatch). Crossed the limit at 2088 LOC after the
+# web-stream correctness batch (#2450 pipeTo preventClose, #2455 BYOB-on-
+# non-byte reject, #2460 reserved-type reject) landed on main without a
+# split. Splitting per stream-kind family is tracked under #2472.
+crates/perry-stdlib/src/streams.rs
 EOF
 )