diff --git a/local/docs/REDBEAR-FULL-SDDM-BRINGUP.md b/local/docs/REDBEAR-FULL-SDDM-BRINGUP.md
index b95ed3fb28..13775b05ad 100644
--- a/local/docs/REDBEAR-FULL-SDDM-BRINGUP.md
+++ b/local/docs/REDBEAR-FULL-SDDM-BRINGUP.md
@@ -39,6 +39,31 @@ From the upstream-forks sweep — fetch + cherry-pick only if we hit these runti
 - relibc `9867c155..707169e2`: **ld.so lazy PLT relocation** (dlopen of libEGL/libgbm), poll/epoll timeout, UDS-connect outside rootfs.
 - base `59cf8189..488da6a1`: ramfs hosting AF_UNIX sockets (Wayland `$XDG_RUNTIME_DIR/wayland-0`).
 
+## Runtime wiring audit (config/redbear-full.toml)
+
+**Greeter compositor:** `/etc/sddm.conf` sets `[Wayland] CompositorCommand=/usr/bin/redbear-compositor`.
+So the SDDM greeter renders on **redbear-compositor** (KWin is the post-login
+session compositor). Rendering the greeter does NOT need the compositor input
+wiring (that only gates typing a login) — so "see the SDDM prompt" is reachable
+without the input refactor.
+
+**Runtime chain (coherent):** `00_driver-manager` sees the GPU PCI device →
+spawns `redox-drm` (priority-61 for virtio/Intel/AMD) → `/scheme/drm/card0` →
+`21_sddm` (`REDBEAR_DRM_WAIT_SECONDS=30` waits for card0) → launches
+`redbear-compositor` → SDDM greeter Qt/Wayland UI. Needs `dbus`, `seatd`,
+`redbear-sessiond`, `redbear-authd` (all `requires_weak` on sddm).
+
+**CONFLICT (must resolve for a clean SDDM greeter):** three display entry points
+all fire as `oneshot_async`, each trying to own the GPU/card0/VT:
+- `20_display.service` → `redbear-session-launch` (KDE session, VT 4)
+- `20_greeter.service` → `redbear-greeterd` (custom RedBear greeter, VT 3)
+- `21_sddm.service` → `sddm` (the target)
+For the SDDM path, `20_display` and `20_greeter` should be disabled (GPU/DRM is
+single-owner). This is a service-removal decision → **needs operator sign-off**
+(policy: only the user authorizes removing services). Options: (a) disable the two
+competing units for the SDDM path, or (b) confirm SDDM is the chosen greeter and
+the others are legacy.
+
 ## Build notes / deficiencies fixed
 - Full builds re-cooked llvm21 (~1-2h) on every base/relibc bump — fixed in Phase 0.
 - Mesa source/ is an untracked build artifact; durable Mesa changes MUST be patches (Phase 1a).