diff --git a/.project/objectives/p3-18-water-crossing-embark-transport.md b/.project/objectives/p3-18-water-crossing-embark-transport.md
index 31a40547..901d4fb0 100644
--- a/.project/objectives/p3-18-water-crossing-embark-transport.md
+++ b/.project/objectives/p3-18-water-crossing-embark-transport.md
@@ -70,12 +70,23 @@ two-tier Civ model on the existing tree (`public/resources/techs/naval.json`):
   the embark tier (mountains/volcano/ice stay blocked). So a teched frontier /
   capital-march army paths across water. Tests `embark_opens_water_for_passability`
   + `embark_never_opens_non_water_impassables`; mc-ai 287 green. Commit `6b41b07f4`.
+- [x] **P3b — delete the Civ-V explicit-embark model (single source).** ✅ Removed
+  `ActionKind::Embark/Disembark`, the 4 embark `DisabledReason`s, the amphibious
+  action-gen block, `handle_embark/handle_disembark` + dispatch, the dead
+  `UnitCapability` embark fields + all fixtures/tests. Auto-embark is now the only
+  embark model. mc-core 263 / mc-ai 287 / mc-turn 244 green. Commit `f830a1ce0`.
+  (api-gdext `legal_actions_for`/`can_invoke` keep the embark FFI inputs as
+  vestigial/ABI-stable — trimmed in P5.)
 - [ ] **P4 — transport load/carry/unload.** Implement the `transport` keyword:
   load adjacent land units (≤ capacity) onto a transport ship, they move with it,
-  unload onto adjacent land. Carried units protected. Unit tests.
-- [ ] **P5 — GDScript pathfinder mirror.** `pathfinder.gd::_is_passable` mirrors
-  the embark gate (or, preferably, the GDScript movement delegates to the Rust
-  pathfinder so there is one implementation — Rail 1).
+  unload onto adjacent land. Carried units protected. Unit tests. *(Large fresh
+  mechanic — cargo state on MapUnit + load/unload + carry-move + combat. Pure
+  Rust, cargo-test verifiable.)*
+- [ ] **P5 — GDScript pathfinder mirror + FFI trim.** `pathfinder.gd::_is_passable`
+  mirrors the embark gate (or delegates to the Rust pathfinder — Rail 1); drop the
+  vestigial embark inputs from `legal_actions_for`/`can_invoke` + their GDScript
+  callers (`unit_panel.gd`, `unit.gd`, `test_unit_actions.gd`). *(Needs the build
+  host: GUT + dylib; local cargo resolver panics on gdextension-api.)*
 - [ ] **P6 — end-to-end.** A headless 1v1 (both sides driven) reaches a decisive
   `game_over` by crossing water to capture the enemy capital — the demo that
   motivated this objective.