diff --git a/nodes/passthrough/src/passthrough_node.cpp b/nodes/passthrough/src/passthrough_node.cpp
index e8acb1c..244c049 100644
--- a/nodes/passthrough/src/passthrough_node.cpp
+++ b/nodes/passthrough/src/passthrough_node.cpp
@@ -28,7 +28,6 @@ void PassthroughNode::on_add_reader(const std::string& port_id, mxlFlowReader re
         auto now = mxlGetTime();
         auto current_index = mxlTimestampToIndex(&grain_rate_, now);
         read_index_ = current_index - READ_DELAY_GRAINS;
-        delivery_deadline_ = mxlIndexToTimestamp(&grain_rate_, read_index_ + 1);
         aligned_ = true;
 
         spdlog::info("Passthrough: reader added, grain_rate={}/{}, read_index={}, delay={} grains",
@@ -55,12 +54,9 @@ void PassthroughNode::process() {
         return;
     }
 
-    auto now = mxlGetTime();
-    if (delivery_deadline_ > now) {
-        auto sleep_ns = delivery_deadline_ - now;
-        if (sleep_ns < 500000000ULL) {
-            mxlSleepUntil(delivery_deadline_);
-        }
+    auto ns_until = mxlGetNsUntilIndex(read_index_, &grain_rate_);
+    if (ns_until > 2000000ULL) {
+        return;
     }
 
     mxlGrainInfo grain_info{};
@@ -70,10 +66,9 @@ void PassthroughNode::process() {
     if (status != MXL_STATUS_OK) {
         if (status == MXL_ERR_OUT_OF_RANGE_TOO_LATE || status == MXL_ERR_OUT_OF_RANGE_TOO_EARLY) {
             auto old_index = read_index_;
-            now = mxlGetTime();
+            auto now = mxlGetTime();
             auto current_index = mxlTimestampToIndex(&grain_rate_, now);
             read_index_ = current_index - READ_DELAY_GRAINS;
-            delivery_deadline_ = mxlIndexToTimestamp(&grain_rate_, read_index_ + 1);
             spdlog::warn("Passthrough: index {} out of range ({}), realigned to {}",
                         old_index, static_cast<int>(status), read_index_);
         }
@@ -87,7 +82,6 @@ void PassthroughNode::process() {
         spdlog::warn("Passthrough: failed to open output grain at index {}: {}",
                     grain_info.index, static_cast<int>(status));
         read_index_++;
-        delivery_deadline_ = mxlIndexToTimestamp(&grain_rate_, read_index_ + 1);
         return;
     }
 
@@ -99,7 +93,6 @@ void PassthroughNode::process() {
     mxlFlowWriterCommitGrain(*writer_, &out_grain);
 
     read_index_++;
-    delivery_deadline_ = mxlIndexToTimestamp(&grain_rate_, read_index_ + 1);
     grains_processed_++;
 
     if (grains_processed_ <= 5 || grains_processed_ % 50 == 0) {
diff --git a/nodes/passthrough/src/passthrough_node.hpp b/nodes/passthrough/src/passthrough_node.hpp
index 8045c4a..c4e519a 100644
--- a/nodes/passthrough/src/passthrough_node.hpp
+++ b/nodes/passthrough/src/passthrough_node.hpp
@@ -39,7 +39,6 @@ private:
     std::optional<mxlFlowWriter> writer_;
     mxlRational grain_rate_{50, 1};
     uint64_t read_index_ = 0;
-    uint64_t delivery_deadline_ = 0;
     uint64_t grains_processed_ = 0;
     bool aligned_ = false;
 };
diff --git a/test.sh b/test.sh
new file mode 100755
index 0000000..838812e
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,51 @@
+#!/bin/bash
+set -e
+
+ENGINE_PORT=${ENGINE_PORT:-9000}
+MXL_DOMAIN=${MXL_DOMAIN:-/tmp/dmf-mxl}
+FLOW_ID=${FLOW_ID:-a0000001-0000-0000-0000-000000000001}
+BASE_URL="http://127.0.0.1:${ENGINE_PORT}"
+
+log() { echo "=== $1 ==="; }
+
+log "Adding passthrough node"
+curl -s -X POST "${BASE_URL}/api/graph/nodes" \
+  -H "Content-Type: application/json" \
+  -d '{"type":"passthrough","id":"pass1"}' | python3 -m json.tool 2>/dev/null || echo ""
+
+log "Starting graph"
+curl -s -X POST "${BASE_URL}/api/graph/start" | python3 -m json.tool 2>/dev/null || echo ""
+
+sleep 1
+
+log "Connecting input to flow ${FLOW_ID}"
+curl -s -X POST "${BASE_URL}/api/graph/nodes/pass1/connect-input" \
+  -H "Content-Type: application/json" \
+  -d "{\"port_id\":\"video_in\",\"flow_id\":\"${FLOW_ID}\"}" | python3 -m json.tool 2>/dev/null || echo ""
+
+log "Connecting output (creates new MXL flow)"
+OUTPUT=$(curl -s -X POST "${BASE_URL}/api/graph/nodes/pass1/connect-output" \
+  -H "Content-Type: application/json" \
+  -d '{"port_id":"video_out"}')
+echo "$OUTPUT" | python3 -m json.tool 2>/dev/null || echo "$OUTPUT"
+
+OUTPUT_FLOW_ID=$(echo "$OUTPUT" | python3 -c "import sys,json; print(json.load(sys.stdin)['flow_id'])" 2>/dev/null)
+
+if [ -n "$OUTPUT_FLOW_ID" ]; then
+  log "Output flow ID: ${OUTPUT_FLOW_ID}"
+  log "To verify with mxl-gst-sink:"
+  echo "  mxl-gst-sink -d ${MXL_DOMAIN} -v ${OUTPUT_FLOW_ID}"
+fi
+
+sleep 3
+
+log "Checking MXL domain"
+mxl-info --domain "${MXL_DOMAIN}" 2>/dev/null || true
+
+log "Sending status command"
+curl -s -X POST "${BASE_URL}/api/graph/nodes/pass1/command" \
+  -H "Content-Type: application/json" \
+  -d '{"cmd":"status"}' | python3 -m json.tool 2>/dev/null || echo ""
+
+log "Graph state"
+curl -s "${BASE_URL}/api/graph" | python3 -m json.tool 2>/dev/null || echo ""