diff --git a/game/__init__.py b/game/__init__.py
new file mode 100644
index 0000000..808560a
--- /dev/null
+++ b/game/__init__.py
@@ -0,0 +1 @@
+"""Pitchwell game package (sim stubs; no Godot required)."""
diff --git a/game/sim/__init__.py b/game/sim/__init__.py
new file mode 100644
index 0000000..a74850a
--- /dev/null
+++ b/game/sim/__init__.py
@@ -0,0 +1,13 @@
+"""Godot-less Pitchwell sim stubs."""
+
+from .pitch_economy import Economy, SumpWell, Worker, START_PITCH, WORKER_LOAD, WELL_CAPACITY, SEEP_PER_SEC
+
+__all__ = [
+    "Economy",
+    "SumpWell",
+    "Worker",
+    "START_PITCH",
+    "WORKER_LOAD",
+    "WELL_CAPACITY",
+    "SEEP_PER_SEC",
+]
diff --git a/game/sim/pitch_economy.py b/game/sim/pitch_economy.py
new file mode 100644
index 0000000..ff784f7
--- /dev/null
+++ b/game/sim/pitch_economy.py
@@ -0,0 +1,67 @@
+"""Pitch economy stub — numbers from docs/GAMEPLAY.md (Sump Wells / Start / Carry)."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+
+
+# GAMEPLAY.md: Start 500 Pitch
+START_PITCH: float = 500.0
+# GAMEPLAY.md: Worker load 100
+WORKER_LOAD: int = 100
+# GAMEPLAY.md: Sump Wells finite 2500, seep +0.4/s while claimed
+WELL_CAPACITY: float = 2500.0
+SEEP_PER_SEC: float = 0.4
+
+
+@dataclass
+class SumpWell:
+    """Finite Pitch node. Claim via finished refinery in radius (GAMEPLAY.md)."""
+
+    remaining: float = WELL_CAPACITY
+    claimed: bool = False
+    has_refinery: bool = False
+
+    def claim_via_refinery(self) -> None:
+        """Claim well by finishing a refinery flag (GAMEPLAY.md)."""
+        self.has_refinery = True
+        self.claimed = True
+
+    def tick_seep(self, dt: float) -> float:
+        """Seep +0.4/s while claimed; depletes remaining. Returns Pitch extracted."""
+        if not self.claimed or self.remaining <= 0.0 or dt <= 0.0:
+            return 0.0
+        extracted = min(self.remaining, SEEP_PER_SEC * dt)
+        self.remaining -= extracted
+        return extracted
+
+
+@dataclass
+class Worker:
+    """Carry load 100 (GAMEPLAY.md). Stub — load cap only for now."""
+
+    load: int = 0
+    capacity: int = WORKER_LOAD
+
+    def can_pick(self, amount: int) -> int:
+        return max(0, min(amount, self.capacity - self.load))
+
+
+@dataclass
+class Economy:
+    """Faction Pitch pool + claimed wells."""
+
+    pitch: float = START_PITCH
+    wells: list[SumpWell] = field(default_factory=list)
+
+    def add_well(self, well: SumpWell | None = None) -> SumpWell:
+        w = well if well is not None else SumpWell()
+        self.wells.append(w)
+        return w
+
+    def tick(self, dt: float) -> float:
+        gained = 0.0
+        for w in self.wells:
+            gained += w.tick_seep(dt)
+        self.pitch += gained
+        return gained
diff --git a/kitchen/patches/D3.md b/kitchen/patches/D3.md
new file mode 100644
index 0000000..0957e73
--- /dev/null
+++ b/kitchen/patches/D3.md
@@ -0,0 +1,21 @@
+# D3 — `@deltoid-loop` Pitch economy stub
+
+**When:** 2026-09-05 ~22:10:20Z  
+**Scope:** Godot-less sim matching `docs/GAMEPLAY.md` Pitch numbers. No Nintendo/KKnD assets. No push.
+
+## Files
+
+| Path | Role |
+|------|------|
+| `game/sim/pitch_economy.py` | SumpWell (2500, seep +0.4/s claimed), Worker load 100, start Pitch 500, claim via refinery |
+| `game/sim/__init__.py` | exports |
+| `game/__init__.py` | package |
+| `scripts/smoke/economy_smoke.py` | 500 → claim → 10s seep → assert gain; exit 0/1 |
+| `scripts/smoke/run_all.sh` | runs economy_smoke (+ hooks if other smokes appear); no `D3-HOOK` in missing headless |
+
+## Verify
+
+```bash
+python3 scripts/smoke/economy_smoke.py
+# expect PASS, exit 0
+```