diff --git a/scripts/benchmark-compose-actions.rs b/scripts/benchmark-compose-actions.rs
new file mode 100644
index 00000000..99f34b17
--- /dev/null
+++ b/scripts/benchmark-compose-actions.rs
@@ -0,0 +1,146 @@
+//! Measure production document export, block formatting and list continuation.
+//! rustc --edition=2024 -O scripts/benchmark-compose-actions.rs -o /tmp/compose-actions
+//! /tmp/compose-actions export uniform 1048576 10
+//! For a matched source baseline, set COMPOSE_DOCUMENT_SOURCE to its absolute
+//! path and build with --cfg benchmark_baseline. One condition per process.
+//! Requested-live heap bytes exclude allocator overhead, layout, painting and
+//! app RSS/PSS. Fixture construction and entered text are outside the action.
+
+use std::{
+    alloc::{GlobalAlloc, Layout, System},
+    sync::atomic::{AtomicUsize, Ordering},
+    time::Instant,
+};
+#[cfg(benchmark_baseline)]
+#[allow(dead_code)]
+mod rich_compose {
+    include!(env!("COMPOSE_DOCUMENT_SOURCE"));
+}
+#[cfg(not(benchmark_baseline))]
+#[allow(dead_code)]
+#[path = "../src/rich_compose.rs"]
+mod rich_compose;
+use rich_compose::RichComposeDocument;
+struct Counter;
+static LIVE: AtomicUsize = AtomicUsize::new(0);
+static PEAK: AtomicUsize = AtomicUsize::new(0);
+static CALLS: AtomicUsize = AtomicUsize::new(0);
+#[global_allocator]
+static ALLOCATOR: Counter = Counter;
+fn grow(bytes: usize) {
+    let live = LIVE.fetch_add(bytes, Ordering::Relaxed) + bytes;
+    PEAK.fetch_max(live, Ordering::Relaxed);
+}
+unsafe impl GlobalAlloc for Counter {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        let pointer = unsafe { System.alloc(layout) };
+        if !pointer.is_null() {
+            grow(layout.size());
+            CALLS.fetch_add(1, Ordering::Relaxed);
+        }
+        pointer
+    }
+    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+        let pointer = unsafe { System.alloc_zeroed(layout) };
+        if !pointer.is_null() {
+            grow(layout.size());
+            CALLS.fetch_add(1, Ordering::Relaxed);
+        }
+        pointer
+    }
+    unsafe fn realloc(&self, pointer: *mut u8, layout: Layout, size: usize) -> *mut u8 {
+        let next = unsafe { System.realloc(pointer, layout, size) };
+        if !next.is_null() {
+            if size >= layout.size() {
+                grow(size - layout.size());
+            } else {
+                LIVE.fetch_sub(layout.size() - size, Ordering::Relaxed);
+            }
+            CALLS.fetch_add(1, Ordering::Relaxed);
+        }
+        next
+    }
+    unsafe fn dealloc(&self, pointer: *mut u8, layout: Layout) {
+        unsafe { System.dealloc(pointer, layout) };
+        LIVE.fetch_sub(layout.size(), Ordering::Relaxed);
+    }
+}
+fn fingerprint(value: &str) -> u64 {
+    value.bytes().fold(0xcbf29ce484222325, |hash, byte| {
+        (hash ^ u64::from(byte)).wrapping_mul(0x100000001b3)
+    })
+}
+fn main() {
+    let args = std::env::args().collect::<Vec<_>>();
+    assert_eq!(args.len(), 5, "expected action scenario bytes samples");
+    let action = args[1].as_str();
+    let scenario = args[2].as_str();
+    assert!(matches!(action, "export" | "block" | "list"));
+    assert!(matches!(scenario, "uniform" | "fragmented" | "linked"));
+    let bytes: usize = args[3].parse().expect("draft bytes");
+    let samples: usize = args[4].parse().expect("samples");
+    assert!((1024..=4 * 1024 * 1024).contains(&bytes));
+    assert!((1..=100).contains(&samples));
+    let base = if action == "list" {
+        format!("• {}", "x".repeat(bytes - 4))
+    } else {
+        "x".repeat(bytes)
+    };
+    let entered = format!("{base}\n");
+    println!(
+        "{{\"schema_version\":1,\"scope\":\"document_requested_heap\",\"action\":\"{action}\",\"scenario\":\"{scenario}\",\"draft_bytes\":{bytes},\"warmup_actions\":1,\"samples\":["
+    );
+    for index in 0..=samples {
+        let mut document = RichComposeDocument::default();
+        let end = base.len() as i32;
+        document.synchronize(&base, end, end);
+        match scenario {
+            "fragmented" => {
+                for mark in 0..32 {
+                    let start = (mark * base.len() / 64) as i32;
+                    document.format("bold", &base, start, start + 1);
+                }
+            }
+            "linked" => {
+                document.set_link("https://example.org/?a=1&b=2", &base, 0, end);
+            }
+            _ => {}
+        }
+        let before = LIVE.load(Ordering::Relaxed);
+        PEAK.store(before, Ordering::Relaxed);
+        CALLS.store(0, Ordering::Relaxed);
+        let started = Instant::now();
+        let output = match action {
+            "export" => document.body_html(),
+            "block" => {
+                document.format("bullet", &base, 0, end);
+                None
+            }
+            "list" => {
+                let end = entered.len() as i32;
+                document.synchronize(&entered, end, end);
+                None
+            }
+            _ => unreachable!(),
+        };
+        let elapsed_us = started.elapsed().as_micros();
+        let peak_extra = PEAK.load(Ordering::Relaxed).saturating_sub(before);
+        let settled_extra = LIVE.load(Ordering::Relaxed) as i128 - before as i128;
+        let allocation_calls = CALLS.load(Ordering::Relaxed);
+        let rendered = output.unwrap_or_else(|| document.body_html().unwrap());
+        if index > 0 {
+            if index > 1 {
+                println!(",");
+            }
+            print!(
+                "{{\"elapsed_us\":{elapsed_us},\"peak_extra_bytes\":{peak_extra},\"settled_extra_bytes\":{settled_extra},\"allocation_calls\":{allocation_calls},\"html_bytes\":{},\"html_fingerprint\":{},\"selection\":[{},{}]}}",
+                rendered.len(),
+                fingerprint(&rendered),
+                document.selection().start,
+                document.selection().end
+            );
+        }
+        std::hint::black_box((&document, &rendered));
+    }
+    println!("\n]}}");
+}