Add layer_dismiss module: a key that drops the layer that delivered it

README.md

@@ -10,3 +10,6 @@ Available modules:
 - `oryx`: Includes the raw hid protocol to connect keyboards to Oryx's live
   training / Keymapp live view / typ.ing live view
 - `keycolors`: Includes per-layer key color change
+- `layer_dismiss`: Adds `KC_LAYER_DISMISS` (`LY_DSMS`), an assignable key that
+  turns off the layer that delivered it, on release, emitting nothing: the
+  lowering half of a toggle, aimed at whichever layer resolved the keypress

layer_dismiss/layer_dismiss.c

@@ -0,0 +1,45 @@
+// Copyright 2026 David Scarpetti
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// Layer Dismiss: an assignable key that turns off the layer that delivered
+// it, on release, and produces no output of its own. Where TG() both raises
+// and lowers one specific layer, KC_LAYER_DISMISS is just the lowering half,
+// aimed at whichever layer resolved the keypress, so the same binding works
+// on any layer it is placed on. It pairs conceptually with Layer Lock, which
+// holds a layer on. This lets one go. On the base layer the key is a
+// deliberate no-op: the root cannot be dismissed.
+//
+// Bound across the unused positions of a transiently-raised layer (for
+// example an automouse layer), it turns every foreign tap into a consumed
+// "wake" gesture: the layer drops, nothing types, and the next keystroke
+// lands on the layout below. Dropping on release rather than press means a
+// rolled-over second keystroke still resolves through the layer's
+// transparency to the layout below, so fast typing after a wake tap loses
+// nothing.
+//
+// Composed with automouse, dropping on release also yields a hold behavior
+// for free: while the key is held, automouse counts it as layer activity
+// and keeps refreshing its timer, so the layer stays open through any
+// pause, and release then drops it instantly. Tap dismisses, hold
+// sustains, release exits. The sustain depends on module order: automouse
+// must be listed before layer_dismiss in the keymap's modules list, so
+// that automouse sees the held key's press before this module consumes it.
+// Listed the other way, tap-to-dismiss still works but a hold no longer
+// counts as activity.
+
+#include QMK_KEYBOARD_H
+
+ASSERT_COMMUNITY_MODULES_MIN_API_VERSION(1, 0, 0);
+
+bool process_record_layer_dismiss(uint16_t keycode, keyrecord_t *record) {
+    if (keycode == KC_LAYER_DISMISS) {
+        if (!record->event.pressed) {
+            uint8_t layer = layer_switch_get_layer(record->event.key);
+            if (layer > 0) {
+                layer_off(layer);
+            }
+        }
+        return false;
+    }
+    return true;
+}

layer_dismiss/qmk_module.json

@@ -0,0 +1,11 @@
+{
+    "module_name": "Layer Dismiss",
+    "maintainer": "David Scarpetti",
+    "license": "GPL-2.0-or-later",
+    "keycodes": [
+        {
+            "key": "KC_LAYER_DISMISS",
+            "aliases": ["LY_DSMS"]
+        }
+    ]
+}