From 7ac6b66b514ba40f0c597e3409701f7b03e2bc47 Mon Sep 17 00:00:00 2001
From: VinPropane <don@donmail.org>
Date: Sat, 4 Apr 2026 23:45:54 -0400
Subject: [PATCH] NS-19: ignore vertical walkable surfaces in ground ray pick

---
 client/scripts/ground_pick.gd | 11 +++++++++++
 server/README.md              |  2 +-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/client/scripts/ground_pick.gd b/client/scripts/ground_pick.gd
index fd2b819..7bef4c8 100644
--- a/client/scripts/ground_pick.gd
+++ b/client/scripts/ground_pick.gd
@@ -1,10 +1,15 @@
 extends Node3D
 
 ## NS-16: walkable ground ray pick. Emits world target for MoveCommand; camera wired from main.
+## NS-19: ignores hits on **steep** surfaces (e.g. pedestal **walls**) so players cannot chain small
+## vertical steps up a vertical face; only **floor-like** normals (high dot with UP) count.
 ## (No `class_name` so headless/CI can load the project before `.godot` import exists.)
 
 signal target_chosen(world: Vector3)
 
+## Minimum `hit_normal.dot(Vector3.UP)` to accept a pick (0 = vertical wall, 1 = flat floor).
+const MIN_WALKABLE_NORMAL_DOT_UP: float = 0.82
+
 ## Fallback when `Viewport.get_camera_3d()` is null (e.g. some editor setups). Set from `main.gd`
 ## in `_ready`.
 var fallback_camera: Camera3D
@@ -36,6 +41,12 @@ func _try_pick(screen_pos: Vector2) -> void:
 	var collider: Variant = hit.get("collider")
 	if not _collider_is_walkable(collider):
 		return
+	var hit_normal: Variant = hit.get("normal", Vector3.ZERO)
+	if hit_normal is not Vector3:
+		return
+	var nrm: Vector3 = (hit_normal as Vector3).normalized()
+	if nrm.dot(Vector3.UP) < MIN_WALKABLE_NORMAL_DOT_UP:
+		return
 	var hit_pos: Variant = hit.get("position")
 	if hit_pos is Vector3:
 		target_chosen.emit(hit_pos as Vector3)
diff --git a/server/README.md b/server/README.md
index e728f22..d62b873 100644
--- a/server/README.md
+++ b/server/README.md
@@ -72,7 +72,7 @@ Unknown player ids return **404**. Full zone sync / replication is still out of
 | `Game:MovementValidation:DistrictBoundsEnabled` | Axis-aligned box on **target** (inclusive min/max) | `false` |
 | `Game:MovementValidation:DistrictMinX` … `DistrictMaxZ` | District extents when enabled | ±12 / Y −2…24 |
 
-**Manual QA (Godot `main.tscn`):** **Green bumps** (~0.15 m rise) stay under default `MaxVerticalStep` from the dev spawn; **orange reject pedestal** top is ~2.5 m above floor so a floor-level click yields **`vertical_step_exceeded`**; **far pad** is beyond default horizontal reach for **`horizontal_step_exceeded`**.
+**Manual QA (Godot `main.tscn`):** **Green bumps** (~0.15 m rise) stay under default `MaxVerticalStep` from the dev spawn; **orange reject pedestal** top is ~2.5 m above floor so a floor-level click yields **`vertical_step_exceeded`**; **far pad** is beyond default horizontal reach for **`horizontal_step_exceeded`**. The client’s **`ground_pick.gd`** only accepts ray hits whose surface **normal** is mostly **upward** (`MIN_WALKABLE_NORMAL_DOT_UP`), so **vertical faces** on the pedestal do not emit move targets—this complements server per-step limits and prevents “stair-stepping” up walls.
 
 Request body (example):