diff --git a/capsules/BLOCK_MAP.md b/capsules/BLOCK_MAP.md
index 734fbb1..68130f0 100644
--- a/capsules/BLOCK_MAP.md
+++ b/capsules/BLOCK_MAP.md
@@ -1,5 +1,5 @@
 # Capsule Block Manifest — Auto-generated
-<!-- Generated by mkcapsule --manifest  2026-08-20T14:53:07Z -->
+<!-- Generated by mkcapsule --manifest  2026-08-21T03:09:23Z -->
 <!-- DO NOT EDIT — re-run mkcapsule --manifest to refresh.  -->
 <!-- Hand-written justifications and immutability notes live  -->
 <!-- in MANIFEST.md alongside this auto-generated index.      -->
diff --git a/disk/artemis.img b/disk/artemis.img
index e99f510..31650b4 100644
Binary files a/disk/artemis.img and b/disk/artemis.img differ
diff --git a/lfs/amd64/starforth b/lfs/amd64/starforth
index 7167862..862dc1b 100755
Binary files a/lfs/amd64/starforth and b/lfs/amd64/starforth differ
diff --git a/src/word_source/starforth_words.c b/src/word_source/starforth_words.c
index bd50c0b..310c486 100644
--- a/src/word_source/starforth_words.c
+++ b/src/word_source/starforth_words.c
@@ -793,6 +793,20 @@ static void starforth_word_zuse_authenticate(VM *vm)
     vm->zuse_session = 1;
 }
 
+/**
+ * @brief Read-only accessor for the canonical heartbeat tick counter
+ *
+ * Stack effect: ( -- n )
+ * Pushes vm->heartbeat.tick_count -- the one clock this project's timing
+ * measurements are supposed to read, not host wall-clock. Read-only: no
+ * corresponding store word exists or should exist.
+ * @param vm Pointer to the VM instance
+ */
+static void starforth_word_heartbeat_ticks(VM* vm)
+{
+    vm_push(vm, (cell_t)vm->heartbeat.tick_count);
+}
+
 /**
  * @brief Register StarForth vocabulary words with the VM
  *
@@ -812,6 +826,7 @@ void register_starforth_words(VM* vm)
     register_word(vm, "RANDOM", starforth_word_random);
     register_word(vm, "WAIT", starforth_word_wait);
     register_word(vm, "ZUSE-AUTHENTICATE", starforth_word_zuse_authenticate);
+    register_word(vm, "HEARTBEAT-TICKS@", starforth_word_heartbeat_ticks);
 
     vm_bootstrap_root_vocabulary(vm, "STARFORTH");
     STARFORTH_CHECK_ARENA("register_starforth_words:post-root");
@@ -829,6 +844,7 @@ void register_starforth_words(VM* vm)
     register_word(vm, "RANDOM", starforth_word_random);
     register_word(vm, "WAIT", starforth_word_wait);
     register_word(vm, "ZUSE-AUTHENTICATE", starforth_word_zuse_authenticate);
+    register_word(vm, "HEARTBEAT-TICKS@", starforth_word_heartbeat_ticks);
 
     vocabulary_word_forth(vm);
     vocabulary_word_definitions(vm);