diff --git a/format.c b/format.c
index 928eb078e..477675a57 100644
--- a/format.c
+++ b/format.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: format.c,v 1.413 2026/08/24 07:26:43 nicm Exp $ */
+/* $OpenBSD: format.c,v 1.414 2026/08/31 19:27:46 nicm Exp $ */
 
 /*
  * Copyright (c) 2011 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1873,6 +1873,37 @@ format_cb_cursor_blinking(struct format_tree *ft)
 	return (NULL);
 }
 
+/* Callback for history_added. */
+static void *
+format_cb_history_added(struct format_tree *ft)
+{
+	if (ft->wp != NULL)
+		return (format_printf("%u", ft->wp->base.grid->scroll_added));
+	return (NULL);
+}
+
+/* Callback for history_collected. */
+static void *
+format_cb_history_collected(struct format_tree *ft)
+{
+	struct window_pane	*wp = ft->wp;
+
+	if (wp != NULL)
+		return (format_printf("%u", wp->base.grid->scroll_collected));
+	return (NULL);
+}
+
+/* Callback for history_generation. */
+static void *
+format_cb_history_generation(struct format_tree *ft)
+{
+	struct window_pane	*wp = ft->wp;
+
+	if (wp != NULL)
+		return (format_printf("%u", wp->base.grid->scroll_generation));
+	return (NULL);
+}
+
 /* Callback for history_limit. */
 static void *
 format_cb_history_limit(struct format_tree *ft)
@@ -3645,12 +3676,21 @@ static const struct format_table_entry format_table[] = {
 	{ "cursor_y", FORMAT_TABLE_STRING,
 	  format_cb_cursor_y
 	},
+	{ "history_added", FORMAT_TABLE_STRING,
+	  format_cb_history_added
+	},
 	{ "history_all_bytes", FORMAT_TABLE_STRING,
 	  format_cb_history_all_bytes
 	},
 	{ "history_bytes", FORMAT_TABLE_STRING,
 	  format_cb_history_bytes
 	},
+	{ "history_collected", FORMAT_TABLE_STRING,
+	  format_cb_history_collected
+	},
+	{ "history_generation", FORMAT_TABLE_STRING,
+	  format_cb_history_generation
+	},
 	{ "history_limit", FORMAT_TABLE_STRING,
 	  format_cb_history_limit
 	},
diff --git a/tmux.1 b/tmux.1
index d2c0a251a..41e0c03e2 100644
--- a/tmux.1
+++ b/tmux.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: tmux.1,v 1.1160 2026/08/31 12:41:03 kirill Exp $
+.\" $OpenBSD: tmux.1,v 1.1161 2026/08/31 19:27:46 nicm Exp $
 .\"
 .\" Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 .\"
@@ -7316,7 +7316,10 @@ The following variables are available, where appropriate:
 .It Li "cursor_very_visible" Ta "" Ta "1 if the cursor is in very visible mode"
 .It Li "cursor_x" Ta "" Ta "Cursor X position in pane"
 .It Li "cursor_y" Ta "" Ta "Cursor Y position in pane"
+.It Li "history_added" Ta "" Ta "Number of lines scrolled into pane history"
 .It Li "history_bytes" Ta "" Ta "Number of bytes in window history"
+.It Li "history_collected" Ta "" Ta "Number of oldest pane history lines discarded at the history limit"
+.It Li "history_generation" Ta "" Ta "Generation incremented when pane history is cleared or reflowed"
 .It Li "history_limit" Ta "" Ta "Maximum window history lines"
 .It Li "history_size" Ta "" Ta "Size of history in lines"
 .It Li "hook" Ta "" Ta "Name of running hook, if any"