diff --git a/AGENTS.md b/AGENTS.md
index ddea69e..856eecb 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -510,4 +510,18 @@ only if packet-attached metadata cannot explain the next failure.
 - [x] Include those timing metrics in segmented mirrored-probe summaries.
 - [x] Add planner tests covering client capture skew, client send skew, server receive skew, and queue ages.
 - [ ] Use the next mirrored run to compare browser p95/drift against client capture/send skew and server receive skew.
-- [ ] If client/server timing is stable while browser p95 still fails, instrument UVC/UAC sink emission timing next.
+- [x] Instrument UVC/UAC/HDMI sink handoff timing before waiting for another run.
+
+## 0.17.26 Blind Timing Window And Sink Handoff Checklist
+
+Context: the next probe should not be required to discover that the server is
+blind between "packet arrived" and "packet handed to UAC/UVC/HDMI". Close
+measurement gaps before tuning any new healing controller.
+
+- [x] Retain rolling client capture/send skew windows inside the server.
+- [x] Retain rolling server receive skew and client queue age windows.
+- [x] Record audio/video sink handoff instants and schedule lateness at the server boundary.
+- [x] Expose sink handoff skew, sink lateness, and rolling p95 timing metrics through `GetUpstreamSync`.
+- [x] Include rolling blind metrics in mirrored-probe CSV/JSONL summaries and blind targets.
+- [x] Add planner tests for rolling timing windows and sink handoff timing.
+- [ ] Use the next mirrored run only for correlation/tuning: decide whether the controller should adjust playout delay, offset, or drop/freeze policy from these blind metrics.
diff --git a/Cargo.lock b/Cargo.lock
index 925182f..ca47ee3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1652,7 +1652,7 @@ checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
 
 [[package]]
 name = "lesavka_client"
-version = "0.17.25"
+version = "0.17.26"
 dependencies = [
  "anyhow",
  "async-stream",
@@ -1686,7 +1686,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_common"
-version = "0.17.25"
+version = "0.17.26"
 dependencies = [
  "anyhow",
  "base64",
@@ -1698,7 +1698,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_server"
-version = "0.17.25"
+version = "0.17.26"
 dependencies = [
  "anyhow",
  "base64",
diff --git a/client/Cargo.toml b/client/Cargo.toml
index 14f2415..b2e818f 100644
--- a/client/Cargo.toml
+++ b/client/Cargo.toml
@@ -4,7 +4,7 @@ path                    = "src/main.rs"
 
 [package]
 name                    = "lesavka_client"
-version                 = "0.17.25"
+version                 = "0.17.26"
 edition                 = "2024"
 
 [dependencies]
diff --git a/client/src/bin/lesavka-relayctl.rs b/client/src/bin/lesavka-relayctl.rs
index 2a8d255..22b83f7 100644
--- a/client/src/bin/lesavka-relayctl.rs
+++ b/client/src/bin/lesavka-relayctl.rs
@@ -321,6 +321,83 @@ fn print_upstream_sync(state: lesavka_common::lesavka::UpstreamSyncState) {
             .map(|value| format!("{value:.1}"))
             .unwrap_or_else(|| "pending".to_string())
     );
+    println!(
+        "planner_client_capture_abs_skew_p95_ms={}",
+        state
+            .client_capture_abs_skew_p95_ms
+            .map(|value| format!("{value:.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_client_send_abs_skew_p95_ms={}",
+        state
+            .client_send_abs_skew_p95_ms
+            .map(|value| format!("{value:.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_server_receive_abs_skew_p95_ms={}",
+        state
+            .server_receive_abs_skew_p95_ms
+            .map(|value| format!("{value:.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_camera_client_queue_age_p95_ms={}",
+        state
+            .camera_client_queue_age_p95_ms
+            .map(|value| format!("{value:.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_microphone_client_queue_age_p95_ms={}",
+        state
+            .microphone_client_queue_age_p95_ms
+            .map(|value| format!("{value:.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_sink_handoff_skew_ms={}",
+        state
+            .sink_handoff_skew_ms
+            .map(|value| format!("{value:+.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_sink_handoff_abs_skew_p95_ms={}",
+        state
+            .sink_handoff_abs_skew_p95_ms
+            .map(|value| format!("{value:.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_camera_sink_late_ms={}",
+        state
+            .camera_sink_late_ms
+            .map(|value| format!("{value:+.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_microphone_sink_late_ms={}",
+        state
+            .microphone_sink_late_ms
+            .map(|value| format!("{value:+.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_camera_sink_late_p95_ms={}",
+        state
+            .camera_sink_late_p95_ms
+            .map(|value| format!("{value:.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
+    println!(
+        "planner_microphone_sink_late_p95_ms={}",
+        state
+            .microphone_sink_late_p95_ms
+            .map(|value| format!("{value:.1}"))
+            .unwrap_or_else(|| "pending".to_string())
+    );
     println!("planner_detail={}", state.last_reason);
 }
 
diff --git a/common/Cargo.toml b/common/Cargo.toml
index e6f2bb3..ad7d76d 100644
--- a/common/Cargo.toml
+++ b/common/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name                    = "lesavka_common"
-version                 = "0.17.25"
+version                 = "0.17.26"
 edition                 = "2024"
 build                   = "build.rs"
 
diff --git a/common/proto/lesavka.proto b/common/proto/lesavka.proto
index 1c9a55b..348e727 100644
--- a/common/proto/lesavka.proto
+++ b/common/proto/lesavka.proto
@@ -125,6 +125,17 @@ message UpstreamSyncState {
   optional float microphone_client_queue_age_ms = 20;
   optional float camera_server_receive_age_ms = 21;
   optional float microphone_server_receive_age_ms = 22;
+  optional float client_capture_abs_skew_p95_ms = 23;
+  optional float client_send_abs_skew_p95_ms = 24;
+  optional float server_receive_abs_skew_p95_ms = 25;
+  optional float camera_client_queue_age_p95_ms = 26;
+  optional float microphone_client_queue_age_p95_ms = 27;
+  optional float sink_handoff_skew_ms = 28;
+  optional float sink_handoff_abs_skew_p95_ms = 29;
+  optional float camera_sink_late_ms = 30;
+  optional float microphone_sink_late_ms = 31;
+  optional float camera_sink_late_p95_ms = 32;
+  optional float microphone_sink_late_p95_ms = 33;
 }
 
 message HandshakeSet  {
diff --git a/scripts/manual/run_upstream_mirrored_av_sync.sh b/scripts/manual/run_upstream_mirrored_av_sync.sh
index c26da5d..c7fd7da 100755
--- a/scripts/manual/run_upstream_mirrored_av_sync.sh
+++ b/scripts/manual/run_upstream_mirrored_av_sync.sh
@@ -861,6 +861,17 @@ for segment in range(1, segment_count + 1):
         "planner_microphone_client_queue_age_ms_after": as_float(planner_after.get("planner_microphone_client_queue_age_ms")),
         "planner_camera_server_receive_age_ms_after": as_float(planner_after.get("planner_camera_server_receive_age_ms")),
         "planner_microphone_server_receive_age_ms_after": as_float(planner_after.get("planner_microphone_server_receive_age_ms")),
+        "planner_client_capture_abs_skew_p95_ms_after": as_float(planner_after.get("planner_client_capture_abs_skew_p95_ms")),
+        "planner_client_send_abs_skew_p95_ms_after": as_float(planner_after.get("planner_client_send_abs_skew_p95_ms")),
+        "planner_server_receive_abs_skew_p95_ms_after": as_float(planner_after.get("planner_server_receive_abs_skew_p95_ms")),
+        "planner_camera_client_queue_age_p95_ms_after": as_float(planner_after.get("planner_camera_client_queue_age_p95_ms")),
+        "planner_microphone_client_queue_age_p95_ms_after": as_float(planner_after.get("planner_microphone_client_queue_age_p95_ms")),
+        "planner_sink_handoff_skew_ms_after": as_float(planner_after.get("planner_sink_handoff_skew_ms")),
+        "planner_sink_handoff_abs_skew_p95_ms_after": as_float(planner_after.get("planner_sink_handoff_abs_skew_p95_ms")),
+        "planner_camera_sink_late_ms_after": as_float(planner_after.get("planner_camera_sink_late_ms")),
+        "planner_microphone_sink_late_ms_after": as_float(planner_after.get("planner_microphone_sink_late_ms")),
+        "planner_camera_sink_late_p95_ms_after": as_float(planner_after.get("planner_camera_sink_late_p95_ms")),
+        "planner_microphone_sink_late_p95_ms_after": as_float(planner_after.get("planner_microphone_sink_late_p95_ms")),
         "active_audio_offset_us_before": as_float(calibration_before.get("calibration_active_audio_offset_us")),
         "active_audio_offset_us_after": as_float(calibration_after.get("calibration_active_audio_offset_us")),
         "active_video_offset_us_before": as_float(calibration_before.get("calibration_active_video_offset_us")),
@@ -939,6 +950,17 @@ if target_source_rows:
         "planner_server_receive_skew_ms_after": range_for(target_source_rows, "planner_server_receive_skew_ms_after"),
         "planner_camera_client_queue_age_ms_after": range_for(target_source_rows, "planner_camera_client_queue_age_ms_after"),
         "planner_microphone_client_queue_age_ms_after": range_for(target_source_rows, "planner_microphone_client_queue_age_ms_after"),
+        "planner_client_capture_abs_skew_p95_ms_after": range_for(target_source_rows, "planner_client_capture_abs_skew_p95_ms_after"),
+        "planner_client_send_abs_skew_p95_ms_after": range_for(target_source_rows, "planner_client_send_abs_skew_p95_ms_after"),
+        "planner_server_receive_abs_skew_p95_ms_after": range_for(target_source_rows, "planner_server_receive_abs_skew_p95_ms_after"),
+        "planner_camera_client_queue_age_p95_ms_after": range_for(target_source_rows, "planner_camera_client_queue_age_p95_ms_after"),
+        "planner_microphone_client_queue_age_p95_ms_after": range_for(target_source_rows, "planner_microphone_client_queue_age_p95_ms_after"),
+        "planner_sink_handoff_skew_ms_after": range_for(target_source_rows, "planner_sink_handoff_skew_ms_after"),
+        "planner_sink_handoff_abs_skew_p95_ms_after": range_for(target_source_rows, "planner_sink_handoff_abs_skew_p95_ms_after"),
+        "planner_camera_sink_late_ms_after": range_for(target_source_rows, "planner_camera_sink_late_ms_after"),
+        "planner_microphone_sink_late_ms_after": range_for(target_source_rows, "planner_microphone_sink_late_ms_after"),
+        "planner_camera_sink_late_p95_ms_after": range_for(target_source_rows, "planner_camera_sink_late_p95_ms_after"),
+        "planner_microphone_sink_late_p95_ms_after": range_for(target_source_rows, "planner_microphone_sink_late_p95_ms_after"),
         "active_audio_offset_us_after": range_for(target_source_rows, "active_audio_offset_us_after"),
         "active_video_offset_us_after": range_for(target_source_rows, "active_video_offset_us_after"),
         "probe_p95_abs_skew_ms": range_for(target_source_rows, "probe_p95_abs_skew_ms"),
diff --git a/server/Cargo.toml b/server/Cargo.toml
index 0496bc7..34e4fc6 100644
--- a/server/Cargo.toml
+++ b/server/Cargo.toml
@@ -10,7 +10,7 @@ bench                   = false
 
 [package]
 name                    = "lesavka_server"
-version                 = "0.17.25"
+version                 = "0.17.26"
 edition                 = "2024"
 autobins                = false
 
diff --git a/server/src/main/relay_service.rs b/server/src/main/relay_service.rs
index 4f135f6..b499e91 100644
--- a/server/src/main/relay_service.rs
+++ b/server/src/main/relay_service.rs
@@ -305,7 +305,7 @@ impl Relay for Handler {
                     tracing::info!(rpc_id, "🎤⬇ srv  pkt#{n}  {} bytes", pkt.data.len());
                 }
                 sink.push(&pkt);
-                upstream_media_rt.mark_audio_presented(pkt.pts);
+                upstream_media_rt.mark_audio_presented(pkt.pts, plan.due_at);
             }
             sink.finish(); // flush on EOS
             let _ = tx.send(Ok(Empty {})).await;
@@ -519,7 +519,7 @@ impl Relay for Handler {
                 startup_video_settled = true;
                 let presented_pts = pkt.pts;
                 relay.feed(pkt); // ← all logging inside video.rs
-                upstream_media_rt.mark_video_presented(presented_pts);
+                upstream_media_rt.mark_video_presented(presented_pts, plan.due_at);
             }
             tx.send(Ok(Empty {})).await.ok();
             Ok::<(), Status>(())
diff --git a/server/src/main/relay_service_coverage.rs b/server/src/main/relay_service_coverage.rs
index 91e8af5..38215c4 100644
--- a/server/src/main/relay_service_coverage.rs
+++ b/server/src/main/relay_service_coverage.rs
@@ -175,7 +175,7 @@ impl Relay for Handler {
                 }
                 pkt.pts = plan.local_pts_us;
                 sink.push(&pkt);
-                upstream_media_rt.mark_audio_presented(pkt.pts);
+                upstream_media_rt.mark_audio_presented(pkt.pts, plan.due_at);
             }
             sink.finish();
             upstream_media_rt.close_microphone(lease.generation);
@@ -264,7 +264,7 @@ impl Relay for Handler {
                 pkt.pts = plan.local_pts_us;
                 let presented_pts = pkt.pts;
                 relay.feed(pkt);
-                upstream_media_rt.mark_video_presented(presented_pts);
+                upstream_media_rt.mark_video_presented(presented_pts, plan.due_at);
             }
             upstream_media_rt.close_camera(upstream_lease.generation);
             tx.send(Ok(Empty {})).await.ok();
diff --git a/server/src/main/rpc_helpers.rs b/server/src/main/rpc_helpers.rs
index 20cdb9d..8c6af1e 100644
--- a/server/src/main/rpc_helpers.rs
+++ b/server/src/main/rpc_helpers.rs
@@ -198,6 +198,35 @@ impl Handler {
             microphone_server_receive_age_ms: snapshot
                 .microphone_server_receive_age_ms
                 .map(|value| value as f32),
+            client_capture_abs_skew_p95_ms: snapshot
+                .client_capture_abs_skew_p95_ms
+                .map(|value| value as f32),
+            client_send_abs_skew_p95_ms: snapshot
+                .client_send_abs_skew_p95_ms
+                .map(|value| value as f32),
+            server_receive_abs_skew_p95_ms: snapshot
+                .server_receive_abs_skew_p95_ms
+                .map(|value| value as f32),
+            camera_client_queue_age_p95_ms: snapshot
+                .camera_client_queue_age_p95_ms
+                .map(|value| value as f32),
+            microphone_client_queue_age_p95_ms: snapshot
+                .microphone_client_queue_age_p95_ms
+                .map(|value| value as f32),
+            sink_handoff_skew_ms: snapshot.sink_handoff_skew_ms.map(|value| value as f32),
+            sink_handoff_abs_skew_p95_ms: snapshot
+                .sink_handoff_abs_skew_p95_ms
+                .map(|value| value as f32),
+            camera_sink_late_ms: snapshot.camera_sink_late_ms.map(|value| value as f32),
+            microphone_sink_late_ms: snapshot
+                .microphone_sink_late_ms
+                .map(|value| value as f32),
+            camera_sink_late_p95_ms: snapshot
+                .camera_sink_late_p95_ms
+                .map(|value| value as f32),
+            microphone_sink_late_p95_ms: snapshot
+                .microphone_sink_late_p95_ms
+                .map(|value| value as f32),
         }))
     }
 }
diff --git a/server/src/upstream_media_runtime.rs b/server/src/upstream_media_runtime.rs
index 5ba9834..e5e6cfc 100644
--- a/server/src/upstream_media_runtime.rs
+++ b/server/src/upstream_media_runtime.rs
@@ -110,11 +110,17 @@ impl UpstreamMediaRuntime {
     }
 
     /// Mark one audio chunk as actually handed to the UAC sink.
-    pub fn mark_audio_presented(&self, local_pts_us: u64) {
+    pub fn mark_audio_presented(&self, local_pts_us: u64, due_at: Instant) {
         let mut state = self
             .state
             .lock()
             .expect("upstream media state mutex poisoned");
+        record_presentation_sample(
+            &mut state,
+            UpstreamMediaKind::Microphone,
+            local_pts_us,
+            due_at,
+        );
         state.last_audio_presented_pts_us = Some(local_pts_us);
         if state.phase != UpstreamSyncPhase::Failed {
             state.phase = UpstreamSyncPhase::Live;
@@ -139,14 +145,16 @@ impl UpstreamMediaRuntime {
             UpstreamMediaKind::Camera => state.latest_camera_timing = Some(sample),
             UpstreamMediaKind::Microphone => state.latest_microphone_timing = Some(sample),
         }
+        record_client_timing_windows(&mut state);
     }
 
     /// Mark one video frame as actually handed to the UVC/HDMI sink.
-    pub fn mark_video_presented(&self, local_pts_us: u64) {
+    pub fn mark_video_presented(&self, local_pts_us: u64, due_at: Instant) {
         let mut state = self
             .state
             .lock()
             .expect("upstream media state mutex poisoned");
+        record_presentation_sample(&mut state, UpstreamMediaKind::Camera, local_pts_us, due_at);
         state.last_video_presented_pts_us = Some(local_pts_us);
         if state.phase != UpstreamSyncPhase::Failed {
             state.phase = UpstreamSyncPhase::Live;
@@ -235,6 +243,19 @@ impl UpstreamMediaRuntime {
                     .as_secs_f64()
                     * 1000.0
             }),
+            client_capture_abs_skew_p95_ms: state.client_capture_skew_window_ms.p95_abs(),
+            client_send_abs_skew_p95_ms: state.client_send_skew_window_ms.p95_abs(),
+            server_receive_abs_skew_p95_ms: state.server_receive_skew_window_ms.p95_abs(),
+            camera_client_queue_age_p95_ms: state.camera_client_queue_age_window_ms.p95(),
+            microphone_client_queue_age_p95_ms: state.microphone_client_queue_age_window_ms.p95(),
+            sink_handoff_skew_ms: latest_sink_handoff_skew_ms(&state),
+            sink_handoff_abs_skew_p95_ms: state.sink_handoff_skew_window_ms.p95_abs(),
+            camera_sink_late_ms: state.latest_camera_presentation.map(presentation_late_ms),
+            microphone_sink_late_ms: state
+                .latest_microphone_presentation
+                .map(presentation_late_ms),
+            camera_sink_late_p95_ms: state.camera_sink_late_window_ms.p95(),
+            microphone_sink_late_p95_ms: state.microphone_sink_late_window_ms.p95(),
         }
     }
 }
@@ -713,6 +734,75 @@ fn instant_delta_us(left: Instant, right: Instant) -> i128 {
     }
 }
 
+fn record_client_timing_windows(state: &mut UpstreamClockState) {
+    let (Some(camera), Some(microphone)) =
+        (state.latest_camera_timing, state.latest_microphone_timing)
+    else {
+        return;
+    };
+    state
+        .client_capture_skew_window_ms
+        .push((camera.capture_pts_us as i128 - microphone.capture_pts_us as i128) as f64 / 1000.0);
+    state
+        .client_send_skew_window_ms
+        .push((camera.send_pts_us as i128 - microphone.send_pts_us as i128) as f64 / 1000.0);
+    state
+        .server_receive_skew_window_ms
+        .push(instant_delta_us(camera.received_at, microphone.received_at) as f64 / 1000.0);
+    state
+        .camera_client_queue_age_window_ms
+        .push(f64::from(camera.queue_age_ms));
+    state
+        .microphone_client_queue_age_window_ms
+        .push(f64::from(microphone.queue_age_ms));
+}
+
+fn record_presentation_sample(
+    state: &mut UpstreamClockState,
+    kind: UpstreamMediaKind,
+    local_pts_us: u64,
+    due_at: Instant,
+) {
+    let sample = state::UpstreamPresentationSample {
+        local_pts_us,
+        due_at,
+        handed_at: Instant::now(),
+    };
+    let late_ms = presentation_late_ms(sample).max(0.0);
+    match kind {
+        UpstreamMediaKind::Camera => {
+            state.latest_camera_presentation = Some(sample);
+            state.camera_sink_late_window_ms.push(late_ms);
+        }
+        UpstreamMediaKind::Microphone => {
+            state.latest_microphone_presentation = Some(sample);
+            state.microphone_sink_late_window_ms.push(late_ms);
+        }
+    }
+    if let Some(skew_ms) = latest_sink_handoff_skew_ms(state) {
+        state.sink_handoff_skew_window_ms.push(skew_ms);
+    }
+}
+
+fn latest_sink_handoff_skew_ms(state: &UpstreamClockState) -> Option<f64> {
+    let (Some(camera), Some(microphone)) = (
+        state.latest_camera_presentation,
+        state.latest_microphone_presentation,
+    ) else {
+        return None;
+    };
+    let local_pts_delta_ms =
+        (camera.local_pts_us as i128 - microphone.local_pts_us as i128).abs() as f64 / 1000.0;
+    if local_pts_delta_ms > 250.0 {
+        return None;
+    }
+    Some(instant_delta_us(camera.handed_at, microphone.handed_at) as f64 / 1000.0)
+}
+
+fn presentation_late_ms(sample: state::UpstreamPresentationSample) -> f64 {
+    instant_delta_us(sample.handed_at, sample.due_at) as f64 / 1000.0
+}
+
 fn refresh_unpaired_pairing_anchor(
     state: &mut UpstreamClockState,
     kind: UpstreamMediaKind,
diff --git a/server/src/upstream_media_runtime/lease_lifecycle.rs b/server/src/upstream_media_runtime/lease_lifecycle.rs
index 0769280..ef5d25b 100644
--- a/server/src/upstream_media_runtime/lease_lifecycle.rs
+++ b/server/src/upstream_media_runtime/lease_lifecycle.rs
@@ -168,6 +168,16 @@ fn reset_timing_anchors(state: &mut UpstreamClockState) {
     state.video_freezes = 0;
     state.latest_camera_timing = None;
     state.latest_microphone_timing = None;
+    state.latest_camera_presentation = None;
+    state.latest_microphone_presentation = None;
+    state.client_capture_skew_window_ms = Default::default();
+    state.client_send_skew_window_ms = Default::default();
+    state.server_receive_skew_window_ms = Default::default();
+    state.camera_client_queue_age_window_ms = Default::default();
+    state.microphone_client_queue_age_window_ms = Default::default();
+    state.sink_handoff_skew_window_ms = Default::default();
+    state.camera_sink_late_window_ms = Default::default();
+    state.microphone_sink_late_window_ms = Default::default();
     state.phase = UpstreamSyncPhase::Acquiring;
     state.last_reason = "timing anchors reset".to_string();
 }
diff --git a/server/src/upstream_media_runtime/state.rs b/server/src/upstream_media_runtime/state.rs
index 7f324e5..67dae52 100644
--- a/server/src/upstream_media_runtime/state.rs
+++ b/server/src/upstream_media_runtime/state.rs
@@ -1,5 +1,8 @@
+use std::collections::VecDeque;
 use tokio::time::Instant;
 
+const TIMING_WINDOW_CAPACITY: usize = 240;
+
 #[derive(Clone, Copy, Debug)]
 pub(super) struct UpstreamTimingSample {
     pub capture_pts_us: u64,
@@ -8,6 +11,45 @@ pub(super) struct UpstreamTimingSample {
     pub received_at: Instant,
 }
 
+#[derive(Clone, Copy, Debug)]
+pub(super) struct UpstreamPresentationSample {
+    pub local_pts_us: u64,
+    pub due_at: Instant,
+    pub handed_at: Instant,
+}
+
+#[derive(Debug, Default)]
+pub(super) struct UpstreamScalarWindow {
+    values: VecDeque<f64>,
+}
+
+impl UpstreamScalarWindow {
+    pub fn push(&mut self, value: f64) {
+        if self.values.len() >= TIMING_WINDOW_CAPACITY {
+            self.values.pop_front();
+        }
+        self.values.push_back(value);
+    }
+
+    pub fn p95_abs(&self) -> Option<f64> {
+        percentile(self.values.iter().map(|value| value.abs()), 0.95)
+    }
+
+    pub fn p95(&self) -> Option<f64> {
+        percentile(self.values.iter().copied(), 0.95)
+    }
+}
+
+fn percentile(values: impl Iterator<Item = f64>, quantile: f64) -> Option<f64> {
+    let mut sorted = values.filter(|value| value.is_finite()).collect::<Vec<_>>();
+    if sorted.is_empty() {
+        return None;
+    }
+    sorted.sort_by(|left, right| left.total_cmp(right));
+    let index = ((sorted.len() - 1) as f64 * quantile.clamp(0.0, 1.0)).ceil() as usize;
+    sorted.get(index).copied()
+}
+
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum UpstreamSyncPhase {
     Acquiring,
@@ -60,6 +102,16 @@ pub(super) struct UpstreamClockState {
     pub last_reason: String,
     pub latest_camera_timing: Option<UpstreamTimingSample>,
     pub latest_microphone_timing: Option<UpstreamTimingSample>,
+    pub latest_camera_presentation: Option<UpstreamPresentationSample>,
+    pub latest_microphone_presentation: Option<UpstreamPresentationSample>,
+    pub client_capture_skew_window_ms: UpstreamScalarWindow,
+    pub client_send_skew_window_ms: UpstreamScalarWindow,
+    pub server_receive_skew_window_ms: UpstreamScalarWindow,
+    pub camera_client_queue_age_window_ms: UpstreamScalarWindow,
+    pub microphone_client_queue_age_window_ms: UpstreamScalarWindow,
+    pub sink_handoff_skew_window_ms: UpstreamScalarWindow,
+    pub camera_sink_late_window_ms: UpstreamScalarWindow,
+    pub microphone_sink_late_window_ms: UpstreamScalarWindow,
 }
 
 impl Default for UpstreamSyncPhase {
diff --git a/server/src/upstream_media_runtime/tests/async_wait.rs b/server/src/upstream_media_runtime/tests/async_wait.rs
index 79dd43e..35a0b10 100644
--- a/server/src/upstream_media_runtime/tests/async_wait.rs
+++ b/server/src/upstream_media_runtime/tests/async_wait.rs
@@ -15,7 +15,7 @@ async fn wait_for_audio_master_releases_video_once_audio_catches_up() {
         super::UpstreamPlanDecision::AwaitingPair
     ));
     let audio_first = play(runtime.plan_audio_pts(1_000_000));
-    runtime.mark_audio_presented(audio_first.local_pts_us);
+    runtime.mark_audio_presented(audio_first.local_pts_us, audio_first.due_at);
     let video_first = play(runtime.plan_video_pts(1_000_000, 16_666));
 
     let waiter = tokio::spawn({
@@ -29,7 +29,7 @@ async fn wait_for_audio_master_releases_video_once_audio_catches_up() {
 
     tokio::time::sleep(Duration::from_millis(5)).await;
     let audio_next = play(runtime.plan_audio_pts(1_010_000));
-    runtime.mark_audio_presented(audio_next.local_pts_us);
+    runtime.mark_audio_presented(audio_next.local_pts_us, audio_next.due_at);
 
     assert!(waiter.await.expect("audio master waiter should finish"));
 }
@@ -47,7 +47,7 @@ async fn wait_for_audio_master_allows_configured_positive_audio_delay() {
         super::UpstreamPlanDecision::AwaitingPair
     ));
     let audio_first = play(runtime.plan_audio_pts(1_000_000));
-    runtime.mark_audio_presented(audio_first.local_pts_us);
+    runtime.mark_audio_presented(audio_first.local_pts_us, audio_first.due_at);
     let _video_first = play(runtime.plan_video_pts(1_000_000, 16_666));
     let delayed_video = play(runtime.plan_video_pts(1_700_000, 16_666));
 
@@ -75,7 +75,7 @@ async fn wait_for_audio_master_times_out_when_audio_never_catches_up() {
         super::UpstreamPlanDecision::AwaitingPair
     ));
     let audio_first = play(runtime.plan_audio_pts(1_000_000));
-    runtime.mark_audio_presented(audio_first.local_pts_us);
+    runtime.mark_audio_presented(audio_first.local_pts_us, audio_first.due_at);
     let video_first = play(runtime.plan_video_pts(1_000_000, 16_666));
 
     let due_at = tokio::time::Instant::now() + Duration::from_millis(20);
@@ -98,7 +98,7 @@ async fn wait_for_audio_master_keeps_video_waiting_through_sync_grace() {
         super::UpstreamPlanDecision::AwaitingPair
     ));
     let audio_first = play(runtime.plan_audio_pts(1_000_000));
-    runtime.mark_audio_presented(audio_first.local_pts_us);
+    runtime.mark_audio_presented(audio_first.local_pts_us, audio_first.due_at);
     let video_first = play(runtime.plan_video_pts(1_000_000, 16_666));
 
     let waiter = tokio::spawn({
@@ -117,7 +117,7 @@ async fn wait_for_audio_master_keeps_video_waiting_through_sync_grace() {
 
     tokio::time::sleep(Duration::from_millis(5)).await;
     let audio_next = play(runtime.plan_audio_pts(1_120_000));
-    runtime.mark_audio_presented(audio_next.local_pts_us);
+    runtime.mark_audio_presented(audio_next.local_pts_us, audio_next.due_at);
 
     assert!(
         waiter
diff --git a/server/src/upstream_media_runtime/tests/planning.rs b/server/src/upstream_media_runtime/tests/planning.rs
index 6655398..4b41997 100644
--- a/server/src/upstream_media_runtime/tests/planning.rs
+++ b/server/src/upstream_media_runtime/tests/planning.rs
@@ -345,7 +345,7 @@ fn video_too_far_behind_audio_master_is_dropped_and_counted_as_freeze() {
             ));
             let audio = play(runtime.plan_audio_pts(1_000_000));
             let _video = play(runtime.plan_video_pts(1_000_000, 16_666));
-            runtime.mark_audio_presented(audio.local_pts_us);
+            runtime.mark_audio_presented(audio.local_pts_us, audio.due_at);
             let audio_master = play(runtime.plan_audio_pts(1_200_000));
 
             assert!(
@@ -355,7 +355,7 @@ fn video_too_far_behind_audio_master_is_dropped_and_counted_as_freeze() {
                 ),
                 "future planned audio alone must not freeze video before UAC presentation"
             );
-            runtime.mark_audio_presented(audio_master.local_pts_us);
+            runtime.mark_audio_presented(audio_master.local_pts_us, audio_master.due_at);
 
             assert!(matches!(
                 runtime.plan_video_pts(1_116_666, 16_666),
@@ -465,8 +465,8 @@ fn planner_snapshot_tracks_presented_playheads_and_skew() {
     ));
     let audio = play(runtime.plan_audio_pts(1_000_000));
     let video = play(runtime.plan_video_pts(1_000_000, 16_666));
-    runtime.mark_audio_presented(audio.local_pts_us);
-    runtime.mark_video_presented(video.local_pts_us);
+    runtime.mark_audio_presented(audio.local_pts_us, audio.due_at);
+    runtime.mark_video_presented(video.local_pts_us, video.due_at);
 
     let snapshot = runtime.snapshot();
     assert_eq!(snapshot.phase, "live");
@@ -475,6 +475,44 @@ fn planner_snapshot_tracks_presented_playheads_and_skew() {
     assert_eq!(snapshot.planner_skew_ms, Some(0.0));
 }
 
+#[test]
+#[serial(upstream_media_runtime)]
+fn planner_snapshot_tracks_sink_handoff_timing_windows() {
+    let runtime = runtime_without_offsets();
+    let _camera = runtime.activate_camera();
+    let _microphone = runtime.activate_microphone();
+    let due_at = tokio::time::Instant::now()
+        .checked_sub(Duration::from_millis(5))
+        .unwrap_or_else(tokio::time::Instant::now);
+
+    runtime.mark_audio_presented(123_000, due_at);
+    std::thread::sleep(Duration::from_millis(1));
+    runtime.mark_video_presented(123_000, due_at);
+
+    let snapshot = runtime.snapshot();
+
+    assert!(
+        snapshot.sink_handoff_skew_ms.is_some_and(|skew| skew > 0.0),
+        "video was handed to its sink after audio"
+    );
+    assert!(
+        snapshot
+            .sink_handoff_abs_skew_p95_ms
+            .is_some_and(|skew| skew > 0.0),
+        "the rolling handoff window should include the audio/video handoff gap"
+    );
+    assert!(
+        snapshot.camera_sink_late_ms.is_some_and(|late| late > 0.0),
+        "handoff after due_at should be reported as positive lateness"
+    );
+    assert!(
+        snapshot
+            .microphone_sink_late_p95_ms
+            .is_some_and(|late| late > 0.0),
+        "audio sink lateness should be retained in the rolling window"
+    );
+}
+
 #[test]
 #[serial(upstream_media_runtime)]
 fn planner_snapshot_tracks_client_timing_sidecar_metrics() {
@@ -504,14 +542,24 @@ fn planner_snapshot_tracks_client_timing_sidecar_metrics() {
 
     assert_eq!(snapshot.client_capture_skew_ms, Some(60.0));
     assert_eq!(snapshot.client_send_skew_ms, Some(50.0));
+    assert_eq!(snapshot.client_capture_abs_skew_p95_ms, Some(60.0));
+    assert_eq!(snapshot.client_send_abs_skew_p95_ms, Some(50.0));
     assert_eq!(snapshot.camera_client_queue_age_ms, Some(20.0));
     assert_eq!(snapshot.microphone_client_queue_age_ms, Some(30.0));
+    assert_eq!(snapshot.camera_client_queue_age_p95_ms, Some(20.0));
+    assert_eq!(snapshot.microphone_client_queue_age_p95_ms, Some(30.0));
     assert!(
         snapshot
             .server_receive_skew_ms
             .is_some_and(|skew| skew < 0.0),
         "camera was received before microphone, so camera-minus-mic receive skew should be negative"
     );
+    assert!(
+        snapshot
+            .server_receive_abs_skew_p95_ms
+            .is_some_and(|skew| skew > 0.0),
+        "server receive jitter should be retained as an absolute p95"
+    );
     assert!(
         snapshot
             .camera_server_receive_age_ms
diff --git a/server/src/upstream_media_runtime/types.rs b/server/src/upstream_media_runtime/types.rs
index e5a8b97..356faa3 100644
--- a/server/src/upstream_media_runtime/types.rs
+++ b/server/src/upstream_media_runtime/types.rs
@@ -89,4 +89,15 @@ pub struct UpstreamPlannerSnapshot {
     pub microphone_client_queue_age_ms: Option<f64>,
     pub camera_server_receive_age_ms: Option<f64>,
     pub microphone_server_receive_age_ms: Option<f64>,
+    pub client_capture_abs_skew_p95_ms: Option<f64>,
+    pub client_send_abs_skew_p95_ms: Option<f64>,
+    pub server_receive_abs_skew_p95_ms: Option<f64>,
+    pub camera_client_queue_age_p95_ms: Option<f64>,
+    pub microphone_client_queue_age_p95_ms: Option<f64>,
+    pub sink_handoff_skew_ms: Option<f64>,
+    pub sink_handoff_abs_skew_p95_ms: Option<f64>,
+    pub camera_sink_late_ms: Option<f64>,
+    pub microphone_sink_late_ms: Option<f64>,
+    pub camera_sink_late_p95_ms: Option<f64>,
+    pub microphone_sink_late_p95_ms: Option<f64>,
 }