diff --git a/proteus/agents/__init__.py b/proteus/agents/__init__.py
deleted file mode 100644
index 6e70073a7613f314174ef407c56ba6321b6f1de8..0000000000000000000000000000000000000000
--- a/proteus/agents/__init__.py
+++ /dev/null
@@ -1,7 +0,0 @@
-"""proteus.agents — slim LLM agent abstraction (no forfeit/stake/risk)."""
-
-from proteus.agents.base import Agent, ActResult, ProbeResult
-from proteus.agents.human import HumanAgent
-from proteus.agents.vanilla import VanillaAgent
-
-__all__ = ["Agent", "ActResult", "ProbeResult", "HumanAgent", "VanillaAgent"]
diff --git a/proteus/cli.py b/proteus/cli.py
index 24a00b82b475e9e2f50147fea09d9a76f4cac5e3..bccfb4dcde9217235fdd34fbe4f1772f63c42fe2 100644
--- a/proteus/cli.py
+++ b/proteus/cli.py
@@ -15,19 +15,19 @@ from __future__ import annotations
 import argparse
 import sys
 
-import proteus.grid  # noqa: F401  — side-effect: populate the scenario registry
-from proteus.agents import HumanAgent, VanillaAgent
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.scenario import list_scenarios
+import proteus.game.scenarios  # noqa: F401  — side-effect: populate the scenario registry
+from proteus.game.agents import HumanAgent, VanillaAgent
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.scenarios.base import list_scenarios
 from proteus.providers import available_providers, make_provider
-from proteus.runtime import SessionRunner, append_trace, read_traces
-from proteus.runtime.memory import (
+from proteus.game.runtime import SessionRunner, append_trace, read_traces
+from proteus.game.runtime.memory import (
     latest_for_model,
     load_checkpoint,
     save_checkpoint,
 )
-from proteus.runtime.memory_gen import generate_memory
-from proteus.runtime.persona import available_personas, get_persona
+from proteus.game.runtime.memory_gen import generate_memory
+from proteus.game.metrics.persona import available_personas, get_persona
 
 
 def _cmd_run(args: argparse.Namespace) -> int:
@@ -100,7 +100,7 @@ def _auto_gif(out_path: str | None, no_gif: bool) -> None:
         return
     from pathlib import Path
 
-    from proteus.viz import reconstruct, write_gif
+    from proteus.game.viz import reconstruct, write_gif
 
     gif_path = Path(out_path).with_suffix(".gif")
     for trace in read_traces(out_path):
@@ -233,7 +233,7 @@ def _cmd_replay(args: argparse.Namespace) -> int:
         return 1
 
     if args.visual or args.png:
-        from proteus.viz import reconstruct, render_terminal, write_pngs
+        from proteus.game.viz import reconstruct, render_terminal, write_pngs
 
         for trace in traces:
             steps = reconstruct(trace)
@@ -264,7 +264,7 @@ def _cmd_replay(args: argparse.Namespace) -> int:
 def _cmd_compare(args: argparse.Namespace) -> int:
     import json
 
-    from proteus.runtime.aggregate import aggregate_traces
+    from proteus.game.metrics.aggregate import aggregate_traces
 
     all_traces = []
     for path in args.trace_files:
diff --git a/proteus/game/__init__.py b/proteus/game/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..98252d84c9030e302d7a79df650c87a0f09198bb
--- /dev/null
+++ b/proteus/game/__init__.py
@@ -0,0 +1,7 @@
+"""proteus.game — the grid game and evaluation engine.
+
+Subpackages: engine (world/physics + vendored ARC engine), scenarios
+(Scenario ABC + registry + concrete scenarios), agents (player interface),
+runtime (session orchestration, trace, memory, I/O), metrics (scoring),
+viz (trace visualization). game never imports proteus.web.
+"""
diff --git a/proteus/game/agents/__init__.py b/proteus/game/agents/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..cc37d8c0c5e601d977e4b3d94082ece9d7e31c70
--- /dev/null
+++ b/proteus/game/agents/__init__.py
@@ -0,0 +1,7 @@
+"""proteus.game.agents — slim LLM agent abstraction (no forfeit/stake/risk)."""
+
+from proteus.game.agents.base import Agent, ActResult, ProbeResult
+from proteus.game.agents.human import HumanAgent
+from proteus.game.agents.vanilla import VanillaAgent
+
+__all__ = ["Agent", "ActResult", "ProbeResult", "HumanAgent", "VanillaAgent"]
diff --git a/proteus/agents/base.py b/proteus/game/agents/base.py
similarity index 100%
rename from proteus/agents/base.py
rename to proteus/game/agents/base.py
diff --git a/proteus/agents/human.py b/proteus/game/agents/human.py
similarity index 97%
rename from proteus/agents/human.py
rename to proteus/game/agents/human.py
index a4a4ea112c8215542f2b10079b90a63767299075..ade6f91b5e9935afc67b96c3ba24059c69ef9fd3 100644
--- a/proteus/agents/human.py
+++ b/proteus/game/agents/human.py
@@ -7,7 +7,7 @@ SessionTrace schema-identical to an LLM trace, so the two compare directly
 input stream — no TTY, no network.
 
 Fairness note: the live view is the ASCII observation the LLM also sees; the
-truecolor / PNG renderers are reserved for post-hoc replay (proteus.viz), so a
+truecolor / PNG renderers are reserved for post-hoc replay (proteus.game.viz), so a
 human baseline reads exactly what the model reads.
 """
 
@@ -16,7 +16,7 @@ from __future__ import annotations
 import builtins
 from typing import Callable, Optional
 
-from proteus.agents.base import Agent, ActResult, ProbeResult
+from proteus.game.agents.base import Agent, ActResult, ProbeResult
 
 # Single-key shortcuts -> canonical action strings (WASD).
 _SHORTCUTS = {"w": "up", "a": "left", "s": "down", "d": "right"}
diff --git a/proteus/agents/parsing.py b/proteus/game/agents/parsing.py
similarity index 100%
rename from proteus/agents/parsing.py
rename to proteus/game/agents/parsing.py
diff --git a/proteus/agents/vanilla.py b/proteus/game/agents/vanilla.py
similarity index 97%
rename from proteus/agents/vanilla.py
rename to proteus/game/agents/vanilla.py
index 8bd4838f23a197f582363be12021094b8ce40798..f14d194f561501c9f5fc4d5cf3f28a02b083afde 100644
--- a/proteus/agents/vanilla.py
+++ b/proteus/game/agents/vanilla.py
@@ -8,8 +8,8 @@ as the agent's reasoning even when the action text is terse.
 
 from __future__ import annotations
 
-from proteus.agents.base import Agent, ActResult, ProbeResult
-from proteus.agents.parsing import extract_action
+from proteus.game.agents.base import Agent, ActResult, ProbeResult
+from proteus.game.agents.parsing import extract_action
 from proteus.providers.base import LLMProvider
 from proteus.providers.thinking_utils import parse_thinking_tags
 
diff --git a/proteus/arc_grid/README.md b/proteus/game/engine/README.md
similarity index 100%
rename from proteus/arc_grid/README.md
rename to proteus/game/engine/README.md
diff --git a/proteus/arc_grid/__init__.py b/proteus/game/engine/__init__.py
similarity index 100%
rename from proteus/arc_grid/__init__.py
rename to proteus/game/engine/__init__.py
diff --git a/proteus/arc_grid/arcengine/LICENSE b/proteus/game/engine/arcengine/LICENSE
similarity index 100%
rename from proteus/arc_grid/arcengine/LICENSE
rename to proteus/game/engine/arcengine/LICENSE
diff --git a/proteus/arc_grid/arcengine/OVERVIEW.md b/proteus/game/engine/arcengine/OVERVIEW.md
similarity index 100%
rename from proteus/arc_grid/arcengine/OVERVIEW.md
rename to proteus/game/engine/arcengine/OVERVIEW.md
diff --git a/proteus/arc_grid/arcengine/__init__.py b/proteus/game/engine/arcengine/__init__.py
similarity index 100%
rename from proteus/arc_grid/arcengine/__init__.py
rename to proteus/game/engine/arcengine/__init__.py
diff --git a/proteus/arc_grid/arcengine/base_game.py b/proteus/game/engine/arcengine/base_game.py
similarity index 100%
rename from proteus/arc_grid/arcengine/base_game.py
rename to proteus/game/engine/arcengine/base_game.py
diff --git a/proteus/arc_grid/arcengine/camera.py b/proteus/game/engine/arcengine/camera.py
similarity index 100%
rename from proteus/arc_grid/arcengine/camera.py
rename to proteus/game/engine/arcengine/camera.py
diff --git a/proteus/arc_grid/arcengine/enums.py b/proteus/game/engine/arcengine/enums.py
similarity index 100%
rename from proteus/arc_grid/arcengine/enums.py
rename to proteus/game/engine/arcengine/enums.py
diff --git a/proteus/arc_grid/arcengine/interfaces.py b/proteus/game/engine/arcengine/interfaces.py
similarity index 100%
rename from proteus/arc_grid/arcengine/interfaces.py
rename to proteus/game/engine/arcengine/interfaces.py
diff --git a/proteus/arc_grid/arcengine/level.py b/proteus/game/engine/arcengine/level.py
similarity index 100%
rename from proteus/arc_grid/arcengine/level.py
rename to proteus/game/engine/arcengine/level.py
diff --git a/proteus/arc_grid/arcengine/py.typed b/proteus/game/engine/arcengine/py.typed
similarity index 100%
rename from proteus/arc_grid/arcengine/py.typed
rename to proteus/game/engine/arcengine/py.typed
diff --git a/proteus/arc_grid/arcengine/sprites.py b/proteus/game/engine/arcengine/sprites.py
similarity index 100%
rename from proteus/arc_grid/arcengine/sprites.py
rename to proteus/game/engine/arcengine/sprites.py
diff --git a/proteus/grid/ascii_view.py b/proteus/game/engine/ascii_view.py
similarity index 100%
rename from proteus/grid/ascii_view.py
rename to proteus/game/engine/ascii_view.py
diff --git a/proteus/grid/difficulty.py b/proteus/game/engine/difficulty.py
similarity index 100%
rename from proteus/grid/difficulty.py
rename to proteus/game/engine/difficulty.py
diff --git a/proteus/grid/game.py b/proteus/game/engine/grid.py
similarity index 97%
rename from proteus/grid/game.py
rename to proteus/game/engine/grid.py
index e3287c85898efe3f825e3ec20f44ae5260249ee1..b46cdf45c4fc9c37798a81fb14888ddad076ce09 100644
--- a/proteus/grid/game.py
+++ b/proteus/game/engine/grid.py
@@ -1,6 +1,6 @@
 """MotiveGridGame — the shared per-turn game loop for the motive_grid family.
 
-``MotiveGridGame`` subclasses ``proteus.arc_grid.ARCBaseGame``.  It owns the
+``MotiveGridGame`` subclasses ``proteus.game.engine.ARCBaseGame``.  It owns the
 turn loop and delegates all scenario-specific behaviour (level construction,
 threat motion, elimination, answer keys) to an injected :class:`Scenario`.
 
@@ -20,7 +20,7 @@ from typing import TYPE_CHECKING
 
 import numpy as np
 
-from proteus.arc_grid import (
+from proteus.game.engine import (
     ARCBaseGame,
     ActionInput,
     Camera,
@@ -30,7 +30,7 @@ from proteus.arc_grid import (
 )
 
 if TYPE_CHECKING:
-    from .scenario import Scenario
+    from ..scenarios.base import Scenario
 
 # Action string -> (dx, dy) grid delta.  y grows downward (arc_grid convention).
 _DIRECTION_DELTAS: dict[str, tuple[int, int]] = {
@@ -217,7 +217,7 @@ class MotiveGridGame(ARCBaseGame):
             name: The sprite name to look up on the current level.
 
         Returns:
-            The matching :class:`~proteus.arc_grid.Sprite`, or ``None``.
+            The matching :class:`~proteus.game.engine.Sprite`, or ``None``.
         """
         sprites = self.current_level.get_sprites_by_name(name)
         return sprites[0] if sprites else None
diff --git a/proteus/arc_grid/rendering.py b/proteus/game/engine/rendering.py
similarity index 100%
rename from proteus/arc_grid/rendering.py
rename to proteus/game/engine/rendering.py
diff --git a/proteus/game/metrics/__init__.py b/proteus/game/metrics/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..1fec8d450ec032d787bb3d01015db74486ca7f1d
--- /dev/null
+++ b/proteus/game/metrics/__init__.py
@@ -0,0 +1,7 @@
+"""proteus.game.metrics — scoring and evaluation.
+
+Submodules: metrics (compute_metrics), persona (PersonaWeights, reference
+policies), rollout (optimal_rollout), aggregate (aggregate_traces). Import the
+submodules directly (e.g. proteus.game.metrics.persona) to avoid an __init__
+import cycle with proteus.game.runtime.trace.
+"""
diff --git a/proteus/runtime/aggregate.py b/proteus/game/metrics/aggregate.py
similarity index 95%
rename from proteus/runtime/aggregate.py
rename to proteus/game/metrics/aggregate.py
index 093456919571311aba45e4f5de393147f0d9f90f..1e66f1a4c0b756314dc3dd9acf9e849a75b241de 100644
--- a/proteus/runtime/aggregate.py
+++ b/proteus/game/metrics/aggregate.py
@@ -6,7 +6,7 @@ Pure functions only (no I/O), so the aggregation is headless-testable. The CLI
 
 from __future__ import annotations
 
-from proteus.runtime.trace import SessionTrace
+from proteus.game.runtime.trace import SessionTrace
 
 
 def aggregate_traces(
diff --git a/proteus/runtime/metrics.py b/proteus/game/metrics/metrics.py
similarity index 99%
rename from proteus/runtime/metrics.py
rename to proteus/game/metrics/metrics.py
index c9caec9e9b3f4fa5de5bf851199ddecd84fd130f..4e962b76c48be71f89065306ab2faea675bb7a59 100644
--- a/proteus/runtime/metrics.py
+++ b/proteus/game/metrics/metrics.py
@@ -34,7 +34,7 @@ the pre-predator position) without redefinition.
 
 from __future__ import annotations
 
-from proteus.runtime.trace import TurnTrace
+from proteus.game.runtime.trace import TurnTrace
 
 
 def compute_metrics(
diff --git a/proteus/runtime/persona.py b/proteus/game/metrics/persona.py
similarity index 100%
rename from proteus/runtime/persona.py
rename to proteus/game/metrics/persona.py
diff --git a/proteus/runtime/rollout.py b/proteus/game/metrics/rollout.py
similarity index 93%
rename from proteus/runtime/rollout.py
rename to proteus/game/metrics/rollout.py
index 11a51689b342c8a8ac024e9c3244f1edd258d8f4..45ef615a271e4817fd2ccceb22b55b61560d762a 100644
--- a/proteus/runtime/rollout.py
+++ b/proteus/game/metrics/rollout.py
@@ -12,9 +12,9 @@ from __future__ import annotations
 import random
 from dataclasses import dataclass
 
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
 
 
 @dataclass(frozen=True)
diff --git a/proteus/runtime/__init__.py b/proteus/game/runtime/__init__.py
similarity index 50%
rename from proteus/runtime/__init__.py
rename to proteus/game/runtime/__init__.py
index 6643b861dc53b0454d9708fcab700d00d9ceb0b1..5f271da8cd9eb6133cd19ff55268a1277a822d81 100644
--- a/proteus/runtime/__init__.py
+++ b/proteus/game/runtime/__init__.py
@@ -1,10 +1,10 @@
-"""proteus.runtime — session orchestration, trace, metrics, and I/O."""
+"""proteus.game.runtime — session orchestration, trace, metrics, and I/O."""
 
-from proteus.runtime.session import SessionRunner
-from proteus.runtime.trace import SessionTrace, TurnTrace
-from proteus.runtime.metrics import compute_metrics
-from proteus.runtime.io import append_trace, read_traces
-from proteus.runtime.memory import (
+from proteus.game.runtime.session import SessionRunner
+from proteus.game.runtime.trace import SessionTrace, TurnTrace
+from proteus.game.metrics.metrics import compute_metrics
+from proteus.game.runtime.io import append_trace, read_traces
+from proteus.game.runtime.memory import (
     MemoryCheckpoint,
     MemoryTurn,
     save_checkpoint,
@@ -12,7 +12,7 @@ from proteus.runtime.memory import (
     latest_for_model,
     render_memory_block,
 )
-from proteus.runtime.memory_gen import generate_memory
+from proteus.game.runtime.memory_gen import generate_memory
 
 __all__ = [
     "SessionRunner",
diff --git a/proteus/runtime/_session_core.py b/proteus/game/runtime/_session_core.py
similarity index 95%
rename from proteus/runtime/_session_core.py
rename to proteus/game/runtime/_session_core.py
index df22b961eec48e7014f460f4892c1fd5eef5d1f0..9786418177b33771595107adb8c64088eea062a7 100644
--- a/proteus/runtime/_session_core.py
+++ b/proteus/game/runtime/_session_core.py
@@ -16,20 +16,20 @@ from dataclasses import dataclass
 
 import numpy as np
 
-from proteus.grid.ascii_view import frame_to_ascii, legend_text
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import Scenario, get_scenario
-from proteus.runtime.memory import MemoryCheckpoint, render_memory_block
-from proteus.runtime.metrics import compute_metrics
-from proteus.runtime.persona import (
+from proteus.game.engine.ascii_view import frame_to_ascii, legend_text
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import Scenario, get_scenario
+from proteus.game.runtime.memory import MemoryCheckpoint, render_memory_block
+from proteus.game.metrics.metrics import compute_metrics
+from proteus.game.metrics.persona import (
     PersonaWeights,
     pressure as persona_pressure,
     reference_actions,
     reward_rw,
 )
-from proteus.runtime.rollout import optimal_rollout
-from proteus.runtime.trace import SessionTrace, TurnTrace
+from proteus.game.metrics.rollout import optimal_rollout
+from proteus.game.runtime.trace import SessionTrace, TurnTrace
 
 _ACTIONS = ["up", "down", "left", "right", "stay"]
 _DIRECTIONS = {"up", "down", "left", "right"}
diff --git a/proteus/runtime/interactive.py b/proteus/game/runtime/interactive.py
similarity index 96%
rename from proteus/runtime/interactive.py
rename to proteus/game/runtime/interactive.py
index af6987d6aac9c9ca70a71cc2a4c7e6efe6ec0689..0ff53c8bc86bae9df9fef6187415185cb8ab725e 100644
--- a/proteus/runtime/interactive.py
+++ b/proteus/game/runtime/interactive.py
@@ -11,9 +11,9 @@ only once the game is over.
 """
 from __future__ import annotations
 
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime import _session_core as core
-from proteus.runtime.trace import SessionTrace, TurnTrace
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime import _session_core as core
+from proteus.game.runtime.trace import SessionTrace, TurnTrace
 
 
 class InteractiveSession:
diff --git a/proteus/runtime/io.py b/proteus/game/runtime/io.py
similarity index 96%
rename from proteus/runtime/io.py
rename to proteus/game/runtime/io.py
index da104f7096fa589793450368c571cce77249c85c..28e4dda6c7032c75dddb435a8230fde4b0237816 100644
--- a/proteus/runtime/io.py
+++ b/proteus/game/runtime/io.py
@@ -10,7 +10,7 @@ from __future__ import annotations
 
 from pathlib import Path
 
-from proteus.runtime.trace import SessionTrace
+from proteus.game.runtime.trace import SessionTrace
 
 
 def append_trace(trace: SessionTrace, path: str | Path) -> Path:
diff --git a/proteus/runtime/memory.py b/proteus/game/runtime/memory.py
similarity index 100%
rename from proteus/runtime/memory.py
rename to proteus/game/runtime/memory.py
diff --git a/proteus/runtime/memory_gen.py b/proteus/game/runtime/memory_gen.py
similarity index 92%
rename from proteus/runtime/memory_gen.py
rename to proteus/game/runtime/memory_gen.py
index 4c4ab07124f16eecc781b523d789235241b1a550..0effe09440afb10deaab715662eba0d74a65a6d9 100644
--- a/proteus/runtime/memory_gen.py
+++ b/proteus/game/runtime/memory_gen.py
@@ -12,13 +12,13 @@ import random
 from datetime import datetime, timezone
 from typing import Callable
 
-from proteus.agents.base import Agent
-from proteus.grid.ascii_view import legend_text
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
-from proteus.runtime.memory import MemoryCheckpoint, MemoryTurn
-from proteus.runtime.persona import PersonaWeights, reference_actions
+from proteus.game.agents.base import Agent
+from proteus.game.engine.ascii_view import legend_text
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
+from proteus.game.runtime.memory import MemoryCheckpoint, MemoryTurn
+from proteus.game.metrics.persona import PersonaWeights, reference_actions
 
 _ACTIONS = ["up", "down", "left", "right", "stay"]
 _REASONING_LIMIT = 2000  # cap stored reasoning so checkpoints stay small
diff --git a/proteus/runtime/memory_policies.py b/proteus/game/runtime/memory_policies.py
similarity index 98%
rename from proteus/runtime/memory_policies.py
rename to proteus/game/runtime/memory_policies.py
index d8061b20b5c216eb2a9a4cca7d10c3b5b283b117..b4ce9c7559a4d3fc3208d2f4f7eaa6722e098be4 100644
--- a/proteus/runtime/memory_policies.py
+++ b/proteus/game/runtime/memory_policies.py
@@ -1,7 +1,7 @@
 """Scripted hand-authored memory policies for pack_evade demonstrations.
 
 Each policy is a deterministic ``policy(scenario, game) -> action`` callable used
-by :func:`proteus.runtime.memory_gen.generate_memory` (the ``policy=`` path) to
+by :func:`proteus.game.runtime.memory_gen.generate_memory` (the ``policy=`` path) to
 produce a 100-turn handover-memory trajectory with a distinct *motive*:
 
 - ``survival_dynamic``  — keep maximum distance from the predator (evade, moving).
diff --git a/proteus/runtime/session.py b/proteus/game/runtime/session.py
similarity index 92%
rename from proteus/runtime/session.py
rename to proteus/game/runtime/session.py
index 3f9dcc658259872b91d43ea7479a34e5a21faa05..418ca7d7f14b4bd515cbdc831ad5400366e3b89d 100644
--- a/proteus/runtime/session.py
+++ b/proteus/game/runtime/session.py
@@ -4,18 +4,18 @@ One session: build the scenario+game from (scenario, seed, difficulty), replay
 the scripted Cut pre-roll, hand control to the agent for up to ``play_turns``
 turns (observation -> optional probe -> act -> apply -> record), and emit a
 scored SessionTrace. The per-session mechanics are shared with InteractiveSession
-via ``proteus.runtime._session_core`` (single source of truth) — including the
+via ``proteus.game.runtime._session_core`` (single source of truth) — including the
 CP7 memory pre-roll (prepended to the turn-1 observation) and the CP8 persona
 reference/regret bookkeeping, both threaded through the shared helpers.
 """
 from __future__ import annotations
 
-from proteus.agents.base import Agent
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime import _session_core as core
-from proteus.runtime.memory import MemoryCheckpoint
-from proteus.runtime.persona import PersonaWeights
-from proteus.runtime.trace import SessionTrace, TurnTrace
+from proteus.game.agents.base import Agent
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime import _session_core as core
+from proteus.game.runtime.memory import MemoryCheckpoint
+from proteus.game.metrics.persona import PersonaWeights
+from proteus.game.runtime.trace import SessionTrace, TurnTrace
 
 
 class SessionRunner:
diff --git a/proteus/runtime/spectate.py b/proteus/game/runtime/spectate.py
similarity index 95%
rename from proteus/runtime/spectate.py
rename to proteus/game/runtime/spectate.py
index 49dde747a5287eec5b2b3956a3e6976a45965ef5..9b8b973a120a2d2b2d63d69a555642d672f81cbb 100644
--- a/proteus/runtime/spectate.py
+++ b/proteus/game/runtime/spectate.py
@@ -11,10 +11,10 @@ model itself still only ever receives the observation passed to ``agent.act``.)
 """
 from __future__ import annotations
 
-from proteus.agents.base import Agent
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime import _session_core as core
-from proteus.runtime.trace import SessionTrace, TurnTrace
+from proteus.game.agents.base import Agent
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime import _session_core as core
+from proteus.game.runtime.trace import SessionTrace, TurnTrace
 
 
 class SpectateSession:
diff --git a/proteus/runtime/trace.py b/proteus/game/runtime/trace.py
similarity index 100%
rename from proteus/runtime/trace.py
rename to proteus/game/runtime/trace.py
diff --git a/proteus/grid/scenarios/__init__.py b/proteus/game/scenarios/__init__.py
similarity index 55%
rename from proteus/grid/scenarios/__init__.py
rename to proteus/game/scenarios/__init__.py
index ca73fbfc7992803d26457bc5a3609ee354a86e4c..e94c798f46d7f1ece526693ae06533313e619684 100644
--- a/proteus/grid/scenarios/__init__.py
+++ b/proteus/game/scenarios/__init__.py
@@ -1,10 +1,10 @@
 """Scenario implementations for the motive_grid family.
 
 Importing this package fires each scenario's ``@register_scenario`` decorator,
-populating the registry in :mod:`proteus.grid.scenario`.
+populating the registry in :mod:`proteus.game.scenarios.base`.
 """
 
-from proteus.grid.scenarios import predator_evade  # noqa: F401  — side-effect: register
-from proteus.grid.scenarios import pack_evade  # noqa: F401  — side-effect: register
+from proteus.game.scenarios import predator_evade  # noqa: F401  — side-effect: register
+from proteus.game.scenarios import pack_evade  # noqa: F401  — side-effect: register
 
 __all__ = ["predator_evade", "pack_evade"]
diff --git a/proteus/grid/scenario.py b/proteus/game/scenarios/base.py
similarity index 96%
rename from proteus/grid/scenario.py
rename to proteus/game/scenarios/base.py
index a8d96233c3e8b18aced395ac26b9227e138a4250..4f07128ca484af4f405ab2c43e65130958b32f3b 100644
--- a/proteus/grid/scenario.py
+++ b/proteus/game/scenarios/base.py
@@ -7,9 +7,9 @@ and the prediction/discrimination answer keys) while the shared turn loop in
 
 Concrete scenarios register themselves via the ``@register_scenario``
 decorator, mirroring the task-module registry at
-``proteus.grid``::
+``proteus.game.scenarios``::
 
-    from proteus.grid.scenario import (
+    from proteus.game.scenarios.base import (
         Scenario, register_scenario,
     )
 
@@ -18,7 +18,7 @@ decorator, mirroring the task-module registry at
         ...
 
     # Elsewhere:
-    from proteus.grid.scenario import get_scenario
+    from proteus.game.scenarios.base import get_scenario
     scenario = get_scenario("predator_evade")()
 
 See ``docs/superpowers/specs/2026-06-01-motive-grid-design.md`` §4 for the
@@ -31,15 +31,15 @@ import random
 from abc import ABC, abstractmethod
 from typing import TYPE_CHECKING
 
-from proteus.arc_grid import Level
+from proteus.game.engine import Level
 
 if TYPE_CHECKING:
     # Imported only for type checking to avoid a runtime circular import:
     # game.py imports scenario.py is NOT done at runtime; instead a Scenario
     # is injected into MotiveGridGame, and the game reads it back here only
     # for annotations.
-    from .game import MotiveGridGame
-    from .difficulty import Difficulty
+    from ..engine.grid import MotiveGridGame
+    from ..engine.difficulty import Difficulty
 
 
 class Scenario(ABC):
@@ -79,7 +79,7 @@ class Scenario(ABC):
             difficulty: The session difficulty band (a ``Difficulty``).
 
         Returns:
-            A freshly built :class:`~proteus.arc_grid.Level`.
+            A freshly built :class:`~proteus.game.engine.Level`.
         """
         raise NotImplementedError
 
@@ -216,7 +216,7 @@ class Scenario(ABC):
         scenarios override this with a compact textual state so the observation
         is not a several-thousand-character grid.
         """
-        from proteus.grid.ascii_view import frame_to_ascii
+        from proteus.game.engine.ascii_view import frame_to_ascii
         return frame_to_ascii(game.current_grid(), self.legend())
 
     def default_memory(self, seed, difficulty):
diff --git a/proteus/grid/scenarios/pack_evade.py b/proteus/game/scenarios/pack_evade.py
similarity index 96%
rename from proteus/grid/scenarios/pack_evade.py
rename to proteus/game/scenarios/pack_evade.py
index b1d82c31f806a7546fd802086d666a7e8201b58c..958df83f438b45dbc7840e33360c8e15e68afff6 100644
--- a/proteus/grid/scenarios/pack_evade.py
+++ b/proteus/game/scenarios/pack_evade.py
@@ -2,7 +2,7 @@
 
 A single 5x5 predator hunts a 3x3 focal agent (the lone survivor of a pack of
 three; the two that were caught live only in the hand-authored handover memory,
-see ``proteus.runtime.pack_evade_memory``). The field is open (no walls), so all
+see ``proteus.game.runtime.pack_evade_memory``). The field is open (no walls), so all
 geometry is **center-to-center Manhattan** — no BFS. There is no habit/diagnostic
 (``optimal_action == habit_action`` always): this is pure evasion.
 
@@ -15,14 +15,14 @@ from __future__ import annotations
 import random
 from typing import TYPE_CHECKING
 
-from proteus.arc_grid import BlockingMode, Level, Sprite
-from proteus.grid.difficulty import Difficulty
+from proteus.game.engine import BlockingMode, Level, Sprite
+from proteus.game.engine.difficulty import Difficulty
 
-from ..scenario import Scenario, register_scenario
+from .base import Scenario, register_scenario
 
 if TYPE_CHECKING:
-    from ..game import MotiveGridGame
-    from proteus.runtime.memory import MemoryCheckpoint
+    from ..engine.grid import MotiveGridGame
+    from proteus.game.runtime.memory import MemoryCheckpoint
 
 BACKGROUND_IDX = 5  # arc_grid Camera default background
 FOCAL_IDX = 1
@@ -441,7 +441,7 @@ class PackEvade(Scenario):
         """True iff the 3x3 focal footprint anchored at *cell* is on-grid + wall-free.
 
         Used only by the shared hidden-persona reference policy
-        (``proteus.runtime.persona``), which calls it on the focal's top-left
+        (``proteus.game.metrics.persona``), which calls it on the focal's top-left
         anchor, so footprint-awareness is exactly the right semantics here.
         """
         return self._footprint_free(game, game.focal_sprite, cell[0], cell[1])
@@ -473,10 +473,10 @@ class PackEvade(Scenario):
         actually plays a pack_evade episode, and that self-play trajectory is the
         handover memory. The eval model sees only the behaviour (the raw weights
         are never serialized) and must infer/maintain the persona. Reuses the
-        CP7/CP8 generator (``proteus.runtime.memory_gen``) in its persona mode.
+        CP7/CP8 generator (``proteus.game.runtime.memory_gen``) in its persona mode.
         """
-        from proteus.runtime.memory_gen import generate_memory
-        from proteus.runtime.persona import get_persona
+        from proteus.game.runtime.memory_gen import generate_memory
+        from proteus.game.metrics.persona import get_persona
 
         return generate_memory(
             "pack_evade", None,
diff --git a/proteus/grid/scenarios/predator_evade.py b/proteus/game/scenarios/predator_evade.py
similarity index 98%
rename from proteus/grid/scenarios/predator_evade.py
rename to proteus/game/scenarios/predator_evade.py
index af1e36771dd801b5750725797416bf5106fe818d..cbd4e73afea4b0b93af74abd1fa0a6403b53b496 100644
--- a/proteus/grid/scenarios/predator_evade.py
+++ b/proteus/game/scenarios/predator_evade.py
@@ -63,13 +63,13 @@ from collections import deque
 from dataclasses import dataclass
 from typing import TYPE_CHECKING
 
-from proteus.arc_grid import BlockingMode, Level, Sprite
-from proteus.grid.difficulty import Difficulty
+from proteus.game.engine import BlockingMode, Level, Sprite
+from proteus.game.engine.difficulty import Difficulty
 
-from ..scenario import Scenario, register_scenario
+from .base import Scenario, register_scenario
 
 if TYPE_CHECKING:
-    from ..game import MotiveGridGame
+    from ..engine.grid import MotiveGridGame
 
 # --------------------------------------------------------------------------- #
 # Palette indices (must match build_level pixels and legend()).
@@ -238,7 +238,7 @@ class PredatorEvade(Scenario):
             difficulty: The session difficulty band.
 
         Returns:
-            A :class:`~proteus.arc_grid.Level` with focal, predator, and walls.
+            A :class:`~proteus.game.engine.Level` with focal, predator, and walls.
         """
         del rng  # deterministic hand-authored layouts
         layout = _LAYOUTS.get(difficulty, _LAYOUTS[Difficulty.EASY])
diff --git a/proteus/viz/__init__.py b/proteus/game/viz/__init__.py
similarity index 67%
rename from proteus/viz/__init__.py
rename to proteus/game/viz/__init__.py
index da387bc5fff4dc2ea5e3b25210a9644a45873e9e..ef08d61fbeb4ab2f93d6a19d065b30ef72f23f89 100644
--- a/proteus/viz/__init__.py
+++ b/proteus/game/viz/__init__.py
@@ -1,4 +1,4 @@
-"""proteus.viz — human/debug visualization of a SessionTrace.
+"""proteus.game.viz — human/debug visualization of a SessionTrace.
 
 Frames are reconstructed by deterministically replaying the trace through the
 real engine (reconstruct), then rendered to the terminal (truecolor + side
@@ -6,15 +6,15 @@ panel) or to per-frame PNGs. matplotlib (the `viz` extra) is imported lazily by
 the PNG writer only, so importing this package stays offline-safe.
 """
 
-from proteus.viz.gif import write_gif
-from proteus.viz.png import write_pngs
-from proteus.viz.reconstruct import (
+from proteus.game.viz.gif import write_gif
+from proteus.game.viz.png import write_pngs
+from proteus.game.viz.reconstruct import (
     FrameMeta,
     FrameStep,
     TraceReconstructionError,
     reconstruct,
 )
-from proteus.viz.terminal import render as render_terminal
+from proteus.game.viz.terminal import render as render_terminal
 
 __all__ = [
     "FrameMeta",
diff --git a/proteus/viz/gif.py b/proteus/game/viz/gif.py
similarity index 93%
rename from proteus/viz/gif.py
rename to proteus/game/viz/gif.py
index 00413fe09d87df5935f74606cc4108dd40688e7c..0184dd510cc95d5226fd080ae5debe2806e29b7e 100644
--- a/proteus/viz/gif.py
+++ b/proteus/game/viz/gif.py
@@ -10,8 +10,8 @@ from __future__ import annotations
 from pathlib import Path
 from typing import Union
 
-from proteus.arc_grid.rendering import COLOR_MAP, frame_to_rgb_array
-from proteus.viz.reconstruct import FrameStep
+from proteus.game.engine.rendering import COLOR_MAP, frame_to_rgb_array
+from proteus.game.viz.reconstruct import FrameStep
 
 
 def write_gif(
diff --git a/proteus/viz/png.py b/proteus/game/viz/png.py
similarity index 94%
rename from proteus/viz/png.py
rename to proteus/game/viz/png.py
index ed8b32d887ebb0679ad5903a5350b92241c5f033..d2f62ebd3672fcdfc451f77c5d2015e8f0ab3109 100644
--- a/proteus/viz/png.py
+++ b/proteus/game/viz/png.py
@@ -12,8 +12,8 @@ from __future__ import annotations
 from pathlib import Path
 from typing import Union
 
-from proteus.arc_grid.rendering import COLOR_MAP, frame_to_rgb_array
-from proteus.viz.reconstruct import FrameStep
+from proteus.game.engine.rendering import COLOR_MAP, frame_to_rgb_array
+from proteus.game.viz.reconstruct import FrameStep
 
 
 def _title(step: FrameStep) -> str:
diff --git a/proteus/viz/reconstruct.py b/proteus/game/viz/reconstruct.py
similarity index 95%
rename from proteus/viz/reconstruct.py
rename to proteus/game/viz/reconstruct.py
index a21ae00c8ae1d1c0f1701f7a00575ca9e33c2b1d..f119a17f1ab45adf027e8cff873a70b82bfe10b0 100644
--- a/proteus/viz/reconstruct.py
+++ b/proteus/game/viz/reconstruct.py
@@ -21,11 +21,11 @@ from dataclasses import dataclass
 
 import numpy as np
 
-from proteus.grid.ascii_view import frame_to_ascii
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
-from proteus.runtime.trace import SessionTrace, TurnTrace
+from proteus.game.engine.ascii_view import frame_to_ascii
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
+from proteus.game.runtime.trace import SessionTrace, TurnTrace
 
 
 class TraceReconstructionError(RuntimeError):
diff --git a/proteus/viz/terminal.py b/proteus/game/viz/terminal.py
similarity index 95%
rename from proteus/viz/terminal.py
rename to proteus/game/viz/terminal.py
index 067bc00a2bfaef56f1f25b6b07785f341b0d59c7..8fbcb7ce2a2b8eb91fd9d5ab579760937a1a9de0 100644
--- a/proteus/viz/terminal.py
+++ b/proteus/game/viz/terminal.py
@@ -15,8 +15,8 @@ from __future__ import annotations
 import time
 from typing import Callable, Optional
 
-from proteus.arc_grid.rendering import COLOR_MAP, hex_to_rgb, rgb_to_ansi
-from proteus.viz.reconstruct import FrameMeta, FrameStep
+from proteus.game.engine.rendering import COLOR_MAP, hex_to_rgb, rgb_to_ansi
+from proteus.game.viz.reconstruct import FrameMeta, FrameStep
 
 _RESET = "\033[0m"
 _BLOCK = "██"
diff --git a/proteus/grid/__init__.py b/proteus/grid/__init__.py
deleted file mode 100644
index b91796c1ef3a8ed4872a9a00fd0318a2a5082519..0000000000000000000000000000000000000000
--- a/proteus/grid/__init__.py
+++ /dev/null
@@ -1,10 +0,0 @@
-"""proteus.grid — the motive_grid scenario family (ported).
-
-Importing this package imports :mod:`proteus.grid.scenarios`, whose
-``@register_scenario`` decorators populate the scenario registry so
-``get_scenario("predator_evade")`` resolves.
-"""
-
-from proteus.grid import scenarios  # noqa: F401  — side-effect: populate registry
-
-__all__ = ["scenarios"]
diff --git a/proteus/shared/__init__.py b/proteus/shared/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..47dcfd61f2778c21286be34b960e93035b4c9350
--- /dev/null
+++ b/proteus/shared/__init__.py
@@ -0,0 +1,6 @@
+"""proteus.shared — cross-cutting vocabulary shared by game and web.
+
+Skeleton for now. Future home for trace/data models hoisted out of
+game.runtime to break the game.runtime <-> game.metrics package cycle
+(see 2026-06-02-proteus-game-web-restructure-design.md §6.1).
+"""
diff --git a/proteus/web/__init__.py b/proteus/web/__init__.py
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..324a50bcfe97e4d4ac4bdbab2fb580aaf8fea60c 100644
--- a/proteus/web/__init__.py
+++ b/proteus/web/__init__.py
@@ -0,0 +1 @@
+"""proteus.web — interface publishing. local (stdlib single-user) + arena (skeleton)."""
diff --git a/proteus/web/__main__.py b/proteus/web/__main__.py
index cb85c208e8ef1ae7358241df279d1a364a33e360..21f423d093728a1b25bb3b6eef95cf8c1dfc7da0 100644
--- a/proteus/web/__main__.py
+++ b/proteus/web/__main__.py
@@ -1,29 +1,4 @@
-"""`python -m proteus.web` — launch the interactive color-grid play server."""
-from __future__ import annotations
+"""`python -m proteus.web` — delegate to the local play server."""
+from proteus.web.local.__main__ import main
 
-import argparse
-
-import proteus.grid  # noqa: F401  (registers scenarios before any request)
-from proteus.web.server import make_server
-
-
-def main(argv: list[str] | None = None) -> int:
-    parser = argparse.ArgumentParser(prog="proteus.web")
-    parser.add_argument("--host", default="127.0.0.1")
-    parser.add_argument("--port", type=int, default=8000)
-    args = parser.parse_args(argv)
-
-    server = make_server(args.host, args.port)
-    host, port = server.server_address[0], server.server_address[1]
-    print(f"PROTEUS arena — open http://{host}:{port}/  (Ctrl-C to stop)")
-    try:
-        server.serve_forever()
-    except KeyboardInterrupt:
-        print("\nstopping.")
-    finally:
-        server.server_close()
-    return 0
-
-
-if __name__ == "__main__":
-    raise SystemExit(main())
+raise SystemExit(main())
diff --git a/proteus/web/arena/__init__.py b/proteus/web/arena/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..2f18318da49ff8ef3b9cfe450885eb51904e144a
--- /dev/null
+++ b/proteus/web/arena/__init__.py
@@ -0,0 +1,6 @@
+"""proteus.web.arena — multi-user competition arena (SKELETON).
+
+Design: docs/superpowers/specs/2026-06-02-arena-leaderboard-db-design.md
+Subpackages: api (REST routes), db (ORM + migrations), leaderboard
+(aggregation), worker (eval queue + runner). Not implemented yet.
+"""
diff --git a/proteus/web/arena/api/__init__.py b/proteus/web/arena/api/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..bcfecf59a1fb4270baa5b5f30fe978a4071a6e0c
--- /dev/null
+++ b/proteus/web/arena/api/__init__.py
@@ -0,0 +1 @@
+"""Arena skeleton — not implemented. See 2026-06-02-arena-leaderboard-db-design.md."""
diff --git a/proteus/web/arena/db/__init__.py b/proteus/web/arena/db/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..bcfecf59a1fb4270baa5b5f30fe978a4071a6e0c
--- /dev/null
+++ b/proteus/web/arena/db/__init__.py
@@ -0,0 +1 @@
+"""Arena skeleton — not implemented. See 2026-06-02-arena-leaderboard-db-design.md."""
diff --git a/proteus/web/arena/leaderboard/__init__.py b/proteus/web/arena/leaderboard/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..bcfecf59a1fb4270baa5b5f30fe978a4071a6e0c
--- /dev/null
+++ b/proteus/web/arena/leaderboard/__init__.py
@@ -0,0 +1 @@
+"""Arena skeleton — not implemented. See 2026-06-02-arena-leaderboard-db-design.md."""
diff --git a/proteus/web/arena/worker/__init__.py b/proteus/web/arena/worker/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..bcfecf59a1fb4270baa5b5f30fe978a4071a6e0c
--- /dev/null
+++ b/proteus/web/arena/worker/__init__.py
@@ -0,0 +1 @@
+"""Arena skeleton — not implemented. See 2026-06-02-arena-leaderboard-db-design.md."""
diff --git a/proteus/web/local/__init__.py b/proteus/web/local/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/proteus/web/local/__main__.py b/proteus/web/local/__main__.py
new file mode 100644
index 0000000000000000000000000000000000000000..4dcb57419b7acf7e72c50c7365ee22970b3f9435
--- /dev/null
+++ b/proteus/web/local/__main__.py
@@ -0,0 +1,29 @@
+"""`python -m proteus.web.local` — launch the interactive color-grid play server."""
+from __future__ import annotations
+
+import argparse
+
+import proteus.game.scenarios  # noqa: F401  (registers scenarios before any request)
+from proteus.web.local.server import make_server
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(prog="proteus.web.local")
+    parser.add_argument("--host", default="127.0.0.1")
+    parser.add_argument("--port", type=int, default=8000)
+    args = parser.parse_args(argv)
+
+    server = make_server(args.host, args.port)
+    host, port = server.server_address[0], server.server_address[1]
+    print(f"PROTEUS arena — open http://{host}:{port}/  (Ctrl-C to stop)")
+    try:
+        server.serve_forever()
+    except KeyboardInterrupt:
+        print("\nstopping.")
+    finally:
+        server.server_close()
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/proteus/web/server.py b/proteus/web/local/server.py
similarity index 91%
rename from proteus/web/server.py
rename to proteus/web/local/server.py
index 32a46fa26586f78d44bae3acb944af7f5571fa19..5bc44350eea98526097f40fbbbcc539db977e327 100644
--- a/proteus/web/server.py
+++ b/proteus/web/local/server.py
@@ -16,12 +16,12 @@ import uuid
 from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
 from pathlib import Path
 
-from proteus.arc_grid.rendering import COLOR_MAP
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.scenario import list_scenarios
-from proteus.runtime import _session_core as core
-from proteus.runtime.interactive import InteractiveSession
-from proteus.runtime.io import append_trace
+from proteus.game.engine.rendering import COLOR_MAP
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.scenarios.base import list_scenarios
+from proteus.game.runtime import _session_core as core
+from proteus.game.runtime.interactive import InteractiveSession
+from proteus.game.runtime.io import append_trace
 
 _STATIC = Path(__file__).parent / "static" / "index.html"
 _DEFAULT_SEED = 42
@@ -66,9 +66,9 @@ def _resolve_web_memory(
         return None, True, None
     if mode == "none":
         return None, False, None
-    from proteus.runtime.memory_gen import generate_memory
+    from proteus.game.runtime.memory_gen import generate_memory
     if mode.startswith("persona"):
-        from proteus.runtime.persona import available_personas, get_persona
+        from proteus.game.metrics.persona import available_personas, get_persona
         pid = mode.split(":", 1)[1] if ":" in mode else "risk_averse"
         try:
             persona = get_persona(pid)
@@ -80,7 +80,7 @@ def _resolve_web_memory(
         )
         return ckpt, False, None
     if mode.startswith("policy:"):
-        from proteus.runtime.memory_policies import available_policies, get_policy
+        from proteus.game.runtime.memory_policies import available_policies, get_policy
         name = mode.split(":", 1)[1]
         try:
             policy = get_policy(name)
@@ -100,20 +100,20 @@ def _resolve_web_memory(
         except Exception as exc:  # missing SDK / key / bad spec -> clear client error
             return None, False, str(exc)
         if mode == "generate":
-            from proteus.agents.vanilla import VanillaAgent
-            from proteus.runtime.memory import save_checkpoint
+            from proteus.game.agents.vanilla import VanillaAgent
+            from proteus.game.runtime.memory import save_checkpoint
             ckpt = generate_memory(
                 scenario, VanillaAgent(provider), difficulty=difficulty, seed=seed,
                 memory_turns=memory_turns, model_name=provider.model_name,
             )
             save_checkpoint(ckpt, root=memory_root)
             return ckpt, False, None
-        from proteus.runtime.memory import latest_for_model
+        from proteus.game.runtime.memory import latest_for_model
         ckpt = latest_for_model(provider.model_name, root=memory_root)
         if ckpt is None:
             return None, False, f"no saved memory for {provider.model_name!r}"
         return ckpt, False, None
-    from proteus.runtime.memory import load_checkpoint
+    from proteus.game.runtime.memory import load_checkpoint
     try:
         return load_checkpoint(mode), False, None
     except FileNotFoundError:
@@ -136,8 +136,8 @@ def _memory_info(session) -> dict:
         "frames": [],
     }
     if mem is not None:
-        from proteus.grid.scenario import get_scenario
-        from proteus.runtime.memory import memory_frames, render_memory_block
+        from proteus.game.scenarios.base import get_scenario
+        from proteus.game.runtime.memory import memory_frames, render_memory_block
         info["block"] = render_memory_block(mem)
         scen = get_scenario(mem.scenario)()
         info["frames"] = memory_frames(
@@ -206,10 +206,10 @@ def _finish(sid: str, body: dict, registry: dict) -> Response:
 
 
 def _create_spectate(body: dict, registry: dict) -> Response:
-    # Lazy imports keep `import proteus.web.server` free of provider SDKs.
-    from proteus.agents.vanilla import VanillaAgent
+    # Lazy imports keep `import proteus.web.local.server` free of provider SDKs.
+    from proteus.game.agents.vanilla import VanillaAgent
     from proteus.providers import make_provider
-    from proteus.runtime.spectate import SpectateSession
+    from proteus.game.runtime.spectate import SpectateSession
     try:
         scenario = body["scenario"]
         difficulty = Difficulty(body.get("difficulty", "easy"))
diff --git a/proteus/web/static/index.html b/proteus/web/local/static/index.html
similarity index 100%
rename from proteus/web/static/index.html
rename to proteus/web/local/static/index.html
diff --git a/tests/agents/test_agent_base.py b/tests/agents/test_agent_base.py
index 71e44cca460b4deabc6ad0edb96d5bb80e0c4130..ccd4c58985822f7882c1d5f78332dc2522a0ddcf 100644
--- a/tests/agents/test_agent_base.py
+++ b/tests/agents/test_agent_base.py
@@ -1,6 +1,6 @@
 import pytest
 
-from proteus.agents.base import Agent, ActResult
+from proteus.game.agents.base import Agent, ActResult
 
 
 def test_actresult_fields():
diff --git a/tests/agents/test_human.py b/tests/agents/test_human.py
index 31eec7a5f830abbbe72104e2316d35105356597e..4058bae80e876c3a9458c228acd7256daee992fc 100644
--- a/tests/agents/test_human.py
+++ b/tests/agents/test_human.py
@@ -1,5 +1,5 @@
-from proteus.agents import HumanAgent
-from proteus.agents.base import ActResult, ProbeResult
+from proteus.game.agents import HumanAgent
+from proteus.game.agents.base import ActResult, ProbeResult
 
 _ACTIONS = ["up", "down", "left", "right", "stay"]
 
diff --git a/tests/agents/test_parsing.py b/tests/agents/test_parsing.py
index 96ab11bfd748a3ca7d0dcfc10a6830d1a7d2927b..04b2b3f01adf037e4e5dba0cfe376f6e57f2c913 100644
--- a/tests/agents/test_parsing.py
+++ b/tests/agents/test_parsing.py
@@ -1,4 +1,4 @@
-from proteus.agents.parsing import extract_action
+from proteus.game.agents.parsing import extract_action
 
 VALID = ["up", "down", "left", "right", "stay"]
 
diff --git a/tests/agents/test_vanilla.py b/tests/agents/test_vanilla.py
index ec78a4f28c5698eef7a6a76a97f45d14972876fa..a389009caa2f6c5e6f270fce2cab00944c377ea0 100644
--- a/tests/agents/test_vanilla.py
+++ b/tests/agents/test_vanilla.py
@@ -1,5 +1,5 @@
 from proteus.providers import FakeProvider
-from proteus.agents import VanillaAgent, ActResult
+from proteus.game.agents import VanillaAgent, ActResult
 
 VALID = ["up", "down", "left", "right", "stay"]
 
@@ -106,7 +106,7 @@ def test_act_prefers_provider_thinking_tokens_when_present():
 
 
 def test_probe_returns_probe_result_with_reasoning_and_tokens():
-    from proteus.agents import ProbeResult
+    from proteus.game.agents import ProbeResult
     provider = FakeProvider(responses=["<think>predator is two cells east</think>go up"])
     result = VanillaAgent(provider).probe("grid", "where is the predator?", "rules")
     assert isinstance(result, ProbeResult)
diff --git a/tests/cli/test_cli.py b/tests/cli/test_cli.py
index 41f8f1ce039dfb51cc91e044908f27b3f34f4264..abdc5ad92c50e33f6b20aa4e821ac51e4fd57e91 100644
--- a/tests/cli/test_cli.py
+++ b/tests/cli/test_cli.py
@@ -1,5 +1,5 @@
 from proteus.cli import main
-from proteus.runtime import read_traces
+from proteus.game.runtime import read_traces
 
 
 def test_list_scenarios_prints_predator_evade(capsys):
diff --git a/tests/cli/test_cli_memory.py b/tests/cli/test_cli_memory.py
index c583a8954d28a6c66f5aa2cd3fecdb617093edc0..0bc4525132709a382f360c4d9cd06cf36de317cd 100644
--- a/tests/cli/test_cli_memory.py
+++ b/tests/cli/test_cli_memory.py
@@ -1,5 +1,5 @@
 from proteus.cli import main
-from proteus.runtime.memory import load_checkpoint
+from proteus.game.runtime.memory import load_checkpoint
 
 
 def test_memory_subcommand_writes_loadable_checkpoint(tmp_path):
@@ -25,7 +25,7 @@ def test_memory_subcommand_unknown_model_exits_2(tmp_path, capsys):
     assert "bogusprovider" in capsys.readouterr().err
 
 
-from proteus.runtime import read_traces
+from proteus.game.runtime import read_traces
 
 
 def test_run_memory_generate_sets_memory_ref(tmp_path):
diff --git a/tests/cli/test_cli_persona.py b/tests/cli/test_cli_persona.py
index 17d09972d5062e2bcde283f4babc0cc4923802ea..4645b3b7ccbbffe5fb146dbb2709ba963943351b 100644
--- a/tests/cli/test_cli_persona.py
+++ b/tests/cli/test_cli_persona.py
@@ -1,5 +1,5 @@
 from proteus.cli import main
-from proteus.runtime import read_traces
+from proteus.game.runtime import read_traces
 
 
 def test_run_with_persona_records_id_and_metrics(tmp_path):
@@ -41,7 +41,7 @@ def test_run_unknown_persona_errors(tmp_path):
 
 
 def test_memory_with_persona_tags_checkpoint(tmp_path):
-    from proteus.runtime.memory import load_checkpoint
+    from proteus.game.runtime.memory import load_checkpoint
     out = tmp_path / "mem.json"
     rc = main([
         "memory", "--scenario", "predator_evade", "--model", "fake:demo",
diff --git a/tests/grid/test_ascii_view.py b/tests/grid/test_ascii_view.py
index e9ada8c288cb7863b2a9d2e80747f68319f84068..8a9150dd2a13d407481cd597492e60b07c4ee458 100644
--- a/tests/grid/test_ascii_view.py
+++ b/tests/grid/test_ascii_view.py
@@ -1,6 +1,6 @@
 import numpy as np
 
-from proteus.grid.ascii_view import frame_to_ascii, legend_text
+from proteus.game.engine.ascii_view import frame_to_ascii, legend_text
 
 
 def test_frame_to_ascii_maps_indices_and_unknowns():
diff --git a/tests/grid/test_difficulty.py b/tests/grid/test_difficulty.py
index fe25720745af853d99005ff884528a69fc99b2e2..01bc6fff94435badb5b48f19184985c184a0c956 100644
--- a/tests/grid/test_difficulty.py
+++ b/tests/grid/test_difficulty.py
@@ -1,4 +1,4 @@
-from proteus.grid.difficulty import Difficulty
+from proteus.game.engine.difficulty import Difficulty
 
 
 def test_difficulty_values():
diff --git a/tests/grid/test_difficulty_layouts.py b/tests/grid/test_difficulty_layouts.py
index b6fafc263b011269ca3da922404c32640bffda99..482f9282468067294d42c7169620ff23cffb4e98 100644
--- a/tests/grid/test_difficulty_layouts.py
+++ b/tests/grid/test_difficulty_layouts.py
@@ -2,9 +2,9 @@ import random
 
 import numpy as np
 
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import Scenario, get_scenario
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import Scenario, get_scenario
 
 
 def _scenario():
diff --git a/tests/grid/test_distance_helpers.py b/tests/grid/test_distance_helpers.py
index 380859fb83e70e63fc4b4c589fce238fd59503b6..176892a20a84881d046a00b2c729b37347c23050 100644
--- a/tests/grid/test_distance_helpers.py
+++ b/tests/grid/test_distance_helpers.py
@@ -1,8 +1,8 @@
 import random
-import proteus.grid  # noqa: F401
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import Scenario, get_scenario
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import Scenario, get_scenario
 
 
 def _game():
diff --git a/tests/grid/test_footprint_bounds.py b/tests/grid/test_footprint_bounds.py
index 527e78b57d785e20509287002f442fe37dc0480b..869cd8a7fd0e6a40400bc61f4008bce2fb206764 100644
--- a/tests/grid/test_footprint_bounds.py
+++ b/tests/grid/test_footprint_bounds.py
@@ -4,10 +4,10 @@ from __future__ import annotations
 
 import random
 
-import proteus.grid  # noqa: F401
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
 
 
 def test_3x3_focal_cannot_leave_grid():
diff --git a/tests/grid/test_game_import.py b/tests/grid/test_game_import.py
index c571e92ee0ddd6045766b13593b389adcd941044..fa910e54bda7da4d929cb6579a9a238ac52f76f6 100644
--- a/tests/grid/test_game_import.py
+++ b/tests/grid/test_game_import.py
@@ -1,5 +1,5 @@
 def test_game_module_imports_and_action_maps_are_consistent():
-    from proteus.grid.game import (
+    from proteus.game.engine.grid import (
         MotiveGridGame,
         _DIRECTION_DELTAS,
         _ACTION_TO_GAMEACTION,
diff --git a/tests/grid/test_pack_evade.py b/tests/grid/test_pack_evade.py
index 4a92eedb55d2f99bc29930a6f81b33e49c052546..76fce1c6d72c2eb5470b8fa1b90c6a4602f7ca17 100644
--- a/tests/grid/test_pack_evade.py
+++ b/tests/grid/test_pack_evade.py
@@ -3,10 +3,10 @@ from __future__ import annotations
 
 import random
 
-import proteus.grid  # noqa: F401  (registers scenarios)
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
+import proteus.game.scenarios  # noqa: F401  (registers scenarios)
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
 
 
 def _game(play_turns=20):
diff --git a/tests/grid/test_pack_evade_food.py b/tests/grid/test_pack_evade_food.py
index b0628ad5fec3ce60438df423535f52bf628aeda0..9633a584ec678874340a0522031a91d0503a420d 100644
--- a/tests/grid/test_pack_evade_food.py
+++ b/tests/grid/test_pack_evade_food.py
@@ -3,10 +3,10 @@ from __future__ import annotations
 
 import random
 
-import proteus.grid  # noqa: F401  (registers scenarios)
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
+import proteus.game.scenarios  # noqa: F401  (registers scenarios)
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
 
 
 def _scn(seed=7, diff=Difficulty.MEDIUM):
diff --git a/tests/grid/test_pack_evade_observation.py b/tests/grid/test_pack_evade_observation.py
index 306469e0ac87edf76ffd3f1dcce52a6e685e766a..549be6d4b01cb846c854715f329ac41304d8a452 100644
--- a/tests/grid/test_pack_evade_observation.py
+++ b/tests/grid/test_pack_evade_observation.py
@@ -4,11 +4,11 @@ from __future__ import annotations
 
 import random
 
-import proteus.grid  # noqa: F401
-from proteus.grid.ascii_view import frame_to_ascii
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.engine.ascii_view import frame_to_ascii
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
 
 
 def test_predator_evade_render_frame_is_unchanged_ascii():
diff --git a/tests/grid/test_pack_evade_walls.py b/tests/grid/test_pack_evade_walls.py
index 8ba84c22d1664d6944d9224efcc11b5df3a652ee..a8a441c3f3cdd8dbd4cd1329878e5d4da7e526fd 100644
--- a/tests/grid/test_pack_evade_walls.py
+++ b/tests/grid/test_pack_evade_walls.py
@@ -3,10 +3,10 @@ from __future__ import annotations
 
 import random
 
-import proteus.grid  # noqa: F401  (registers scenarios)
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
+import proteus.game.scenarios  # noqa: F401  (registers scenarios)
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
 
 
 def _scn(seed=7, diff=Difficulty.MEDIUM):
diff --git a/tests/grid/test_predator_evade_behavior.py b/tests/grid/test_predator_evade_behavior.py
index f67f4300c03b913ce1be026a73f41220d52920d0..c3b0dfbe8050eb7f924dd30e8864f1fc84cd6d1d 100644
--- a/tests/grid/test_predator_evade_behavior.py
+++ b/tests/grid/test_predator_evade_behavior.py
@@ -1,8 +1,8 @@
 import random
 
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
 
 
 def _build_at_handover():
diff --git a/tests/grid/test_predator_evade_registered.py b/tests/grid/test_predator_evade_registered.py
index 36d3e8a4e11c0581e746f113899e325101b91f8c..8d3c1512fb6a3d8b853858ed57430cdb8c5be12d 100644
--- a/tests/grid/test_predator_evade_registered.py
+++ b/tests/grid/test_predator_evade_registered.py
@@ -1,6 +1,6 @@
 def test_importing_proteus_grid_registers_predator_evade():
-    import proteus.grid  # noqa: F401  (side-effect: registers scenarios)
-    from proteus.grid.scenario import get_scenario, list_scenarios
+    import proteus.game.scenarios  # noqa: F401  (side-effect: registers scenarios)
+    from proteus.game.scenarios.base import get_scenario, list_scenarios
     assert "predator_evade" in list_scenarios()
     cls = get_scenario("predator_evade")
     inst = cls()
diff --git a/tests/grid/test_scenario_registry.py b/tests/grid/test_scenario_registry.py
index 7cbb7068d64b9b10caffd6c87429a0a5f20bdea4..4eddf2611b4d5638acdd650269e15f74e16a54cd 100644
--- a/tests/grid/test_scenario_registry.py
+++ b/tests/grid/test_scenario_registry.py
@@ -1,6 +1,6 @@
 import pytest
 
-from proteus.grid.scenario import (
+from proteus.game.scenarios.base import (
     Scenario,
     register_scenario,
     get_scenario,
diff --git a/tests/grid/test_step_reward.py b/tests/grid/test_step_reward.py
index b97e3ab25a0c35e9c7e3e02c29446fe57c640575..f089c8d6f16712538d28eb7626785e8c96dff7b7 100644
--- a/tests/grid/test_step_reward.py
+++ b/tests/grid/test_step_reward.py
@@ -1,8 +1,8 @@
 import random
 
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
 
 
 def _handover():
diff --git a/tests/runtime/test_aggregate.py b/tests/runtime/test_aggregate.py
index b763f10dd6a5df5b04e1d793c2dbfc07967ddda5..446b0458deff7a4fdf9b2e0d9916eaa4eab962f3 100644
--- a/tests/runtime/test_aggregate.py
+++ b/tests/runtime/test_aggregate.py
@@ -1,7 +1,7 @@
-from proteus.agents import VanillaAgent
+from proteus.game.agents import VanillaAgent
 from proteus.providers import FakeProvider
-from proteus.runtime.aggregate import aggregate_traces
-from proteus.runtime.session import SessionRunner
+from proteus.game.metrics.aggregate import aggregate_traces
+from proteus.game.runtime.session import SessionRunner
 
 
 def _trace(seed):
diff --git a/tests/runtime/test_auto_regressive.py b/tests/runtime/test_auto_regressive.py
index a582b0314e3430aedda46030c4a4faa3f093fe82..a9414285a58164d4632acdadb2bc3c4a2e190aef 100644
--- a/tests/runtime/test_auto_regressive.py
+++ b/tests/runtime/test_auto_regressive.py
@@ -3,10 +3,10 @@ OWN prior moves this run AND the handover memory every turn (not just turn 1,
 not just the current grid) — so a stateless agent can maintain its trajectory."""
 from __future__ import annotations
 
-import proteus.grid  # noqa: F401
-from proteus.agents.human import HumanAgent
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime.session import SessionRunner
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.agents.human import HumanAgent
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime.session import SessionRunner
 
 
 def _human(actions):
diff --git a/tests/runtime/test_human_comparability.py b/tests/runtime/test_human_comparability.py
index 61fc59ac9652d62ca01f89c3197132301e61006a..617f7856f4a717f26db400e9eb17f66b57e1e55a 100644
--- a/tests/runtime/test_human_comparability.py
+++ b/tests/runtime/test_human_comparability.py
@@ -1,6 +1,6 @@
-from proteus.agents import HumanAgent, VanillaAgent
+from proteus.game.agents import HumanAgent, VanillaAgent
 from proteus.providers import FakeProvider
-from proteus.runtime.session import SessionRunner
+from proteus.game.runtime.session import SessionRunner
 
 
 def _scripted(seq):
diff --git a/tests/runtime/test_integration_golden.py b/tests/runtime/test_integration_golden.py
index 3fc6f616f4acf18c0cedb511a2b4ba25c8b36452..f292896618d04c36005e04eaf06f0bea0fc226ec 100644
--- a/tests/runtime/test_integration_golden.py
+++ b/tests/runtime/test_integration_golden.py
@@ -1,8 +1,8 @@
 import json
 
-from proteus.runtime import SessionRunner, SessionTrace
+from proteus.game.runtime import SessionRunner, SessionTrace
 from proteus.providers import FakeProvider
-from proteus.agents import VanillaAgent
+from proteus.game.agents import VanillaAgent
 
 
 def test_full_session_serializes_to_jsonl_and_reloads():
diff --git a/tests/runtime/test_interactive_equivalence.py b/tests/runtime/test_interactive_equivalence.py
index 67e03675272653b6efa7d21bc00bcf6075748ac2..29afe0a7808f13795a47e24ce52020768040f3f3 100644
--- a/tests/runtime/test_interactive_equivalence.py
+++ b/tests/runtime/test_interactive_equivalence.py
@@ -3,11 +3,11 @@ driven through InteractiveSession (HTTP path) or SessionRunner + a scripted
 HumanAgent (CLI path). This pins the two paths together so they cannot drift."""
 from __future__ import annotations
 
-import proteus.grid  # noqa: F401
-from proteus.agents.human import HumanAgent
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime.interactive import InteractiveSession
-from proteus.runtime.session import SessionRunner
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.agents.human import HumanAgent
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime.interactive import InteractiveSession
+from proteus.game.runtime.session import SessionRunner
 
 ACTIONS = ["up", "up", "left", "stay", "right", "up"]
 
diff --git a/tests/runtime/test_interactive_session.py b/tests/runtime/test_interactive_session.py
index 83b934d2753609505de7b6b658de13574316356f..4bb220997e71a72b453cbaa1bf94d048ff0fc865 100644
--- a/tests/runtime/test_interactive_session.py
+++ b/tests/runtime/test_interactive_session.py
@@ -3,10 +3,10 @@ from __future__ import annotations
 
 import pytest
 
-import proteus.grid  # noqa: F401
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime._session_core import SessionFinishedError
-from proteus.runtime.interactive import InteractiveSession
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime._session_core import SessionFinishedError
+from proteus.game.runtime.interactive import InteractiveSession
 
 
 def _new(play_turns=10):
diff --git a/tests/runtime/test_io.py b/tests/runtime/test_io.py
index 19ab77704121c19a1ccf97fd23dcb4422d7cee41..d37a1f4e82a193c15b09c43fbd10ec17aaf4e2cd 100644
--- a/tests/runtime/test_io.py
+++ b/tests/runtime/test_io.py
@@ -1,6 +1,6 @@
-from proteus.agents import VanillaAgent
+from proteus.game.agents import VanillaAgent
 from proteus.providers import FakeProvider
-from proteus.runtime import SessionRunner, append_trace, read_traces
+from proteus.game.runtime import SessionRunner, append_trace, read_traces
 
 
 def _trace(seed):
diff --git a/tests/runtime/test_memory.py b/tests/runtime/test_memory.py
index 12cbc40529981f81ecec745d83db6dd993850832..47907baa84fe049991b80a721e2409fccd141e78 100644
--- a/tests/runtime/test_memory.py
+++ b/tests/runtime/test_memory.py
@@ -1,4 +1,4 @@
-from proteus.runtime.memory import MemoryCheckpoint, MemoryTurn
+from proteus.game.runtime.memory import MemoryCheckpoint, MemoryTurn
 
 
 def _checkpoint() -> MemoryCheckpoint:
@@ -40,7 +40,7 @@ def test_checkpoint_defaults():
 
 
 def test_save_and_load_round_trip(tmp_path):
-    from proteus.runtime.memory import save_checkpoint, load_checkpoint
+    from proteus.game.runtime.memory import save_checkpoint, load_checkpoint
 
     ck = _checkpoint()
     path = save_checkpoint(ck, root=tmp_path)
@@ -53,7 +53,7 @@ def test_save_and_load_round_trip(tmp_path):
 
 
 def test_load_missing_raises(tmp_path):
-    from proteus.runtime.memory import load_checkpoint
+    from proteus.game.runtime.memory import load_checkpoint
 
     import pytest
     with pytest.raises(FileNotFoundError):
@@ -61,7 +61,7 @@ def test_load_missing_raises(tmp_path):
 
 
 def test_latest_for_model_picks_newest(tmp_path):
-    from proteus.runtime.memory import save_checkpoint, latest_for_model
+    from proteus.game.runtime.memory import save_checkpoint, latest_for_model
 
     older = _checkpoint()
     older.created_at = "2026-06-02T09-00-00Z"
@@ -76,13 +76,13 @@ def test_latest_for_model_picks_newest(tmp_path):
 
 
 def test_latest_for_model_none_when_absent(tmp_path):
-    from proteus.runtime.memory import latest_for_model
+    from proteus.game.runtime.memory import latest_for_model
 
     assert latest_for_model("nobody", root=tmp_path) is None
 
 
 def test_render_memory_block_contains_frames_and_actions():
-    from proteus.runtime.memory import render_memory_block
+    from proteus.game.runtime.memory import render_memory_block
 
     ck = _checkpoint()
     block = render_memory_block(ck)
@@ -92,7 +92,7 @@ def test_render_memory_block_contains_frames_and_actions():
 
 
 def test_render_memory_block_empty_episode():
-    from proteus.runtime.memory import MemoryCheckpoint, render_memory_block
+    from proteus.game.runtime.memory import MemoryCheckpoint, render_memory_block
 
     ck = MemoryCheckpoint(
         model="m", scenario="s", difficulty="easy", seed=None,
@@ -104,7 +104,7 @@ def test_render_memory_block_empty_episode():
 
 
 def test_checkpoint_wall_rects_defaults_empty_and_roundtrips():
-    from proteus.runtime.memory import MemoryCheckpoint
+    from proteus.game.runtime.memory import MemoryCheckpoint
     ck = MemoryCheckpoint(
         model="m", scenario="pack_evade", difficulty="easy", seed=1,
         created_at="2026-01-01T00-00-00Z", outcome="survived",
@@ -122,4 +122,4 @@ def test_checkpoint_wall_rects_defaults_empty_and_roundtrips():
 
 
 def test_memory_symbols_exported_from_runtime():
-    from proteus.runtime import MemoryCheckpoint, save_checkpoint  # noqa: F401
+    from proteus.game.runtime import MemoryCheckpoint, save_checkpoint  # noqa: F401
diff --git a/tests/runtime/test_memory_frames.py b/tests/runtime/test_memory_frames.py
index a06b2d2a18f91bb0dfdb5c12fe1fa1774343e08c..1efc8ea4e49bf75279f2ab67cbaccb9a27abb5ec 100644
--- a/tests/runtime/test_memory_frames.py
+++ b/tests/runtime/test_memory_frames.py
@@ -1,7 +1,7 @@
 """Pure reconstruction of per-turn color grids from a MemoryCheckpoint."""
 from __future__ import annotations
 
-from proteus.runtime.memory import MemoryCheckpoint, MemoryTurn, memory_frames
+from proteus.game.runtime.memory import MemoryCheckpoint, MemoryTurn, memory_frames
 
 _GRID_LEGEND = {5: ".", 1: "A", 2: "B", 3: "#"}
 
@@ -50,7 +50,7 @@ def test_prose_frame_paints_food_cells():
 
 
 def test_checkpoint_food_cells_roundtrips():
-    from proteus.runtime.memory import MemoryCheckpoint
+    from proteus.game.runtime.memory import MemoryCheckpoint
     ck = MemoryCheckpoint(
         model="m", scenario="pack_evade", difficulty="easy", seed=1,
         created_at="t", outcome="survived", transparent_prompt="x",
diff --git a/tests/runtime/test_memory_gen.py b/tests/runtime/test_memory_gen.py
index 3a5aa6fb769d099d49382e811f18bd421d0c01a7..6d4979de228e9c5a7c4605102a3d9b3068084019 100644
--- a/tests/runtime/test_memory_gen.py
+++ b/tests/runtime/test_memory_gen.py
@@ -1,5 +1,5 @@
-import proteus.grid  # noqa: F401  (registers predator_evade)
-from proteus.grid.scenario import Scenario, get_scenario
+import proteus.game.scenarios  # noqa: F401  (registers predator_evade)
+from proteus.game.scenarios.base import Scenario, get_scenario
 
 
 def test_scenario_base_memory_brief_default_empty():
@@ -15,8 +15,8 @@ def test_predator_evade_memory_brief_is_transparent():
     assert "shortest" in low or "bfs" in low  # discloses the chase rule
 
 
-from proteus.agents import VanillaAgent
-from proteus.grid.difficulty import Difficulty
+from proteus.game.agents import VanillaAgent
+from proteus.game.engine.difficulty import Difficulty
 from proteus.providers import FakeProvider
 
 
@@ -25,7 +25,7 @@ def _agent(action: str = "down", n: int = 20) -> VanillaAgent:
 
 
 def test_generate_memory_is_deterministic_and_records_episode():
-    from proteus.runtime.memory_gen import generate_memory
+    from proteus.game.runtime.memory_gen import generate_memory
 
     ck = generate_memory(
         "predator_evade", _agent(), difficulty=Difficulty.EASY, seed=42,
@@ -48,7 +48,7 @@ def test_generate_memory_is_deterministic_and_records_episode():
 
 
 def test_generate_memory_uses_memory_brief_as_prompt():
-    from proteus.runtime.memory_gen import generate_memory
+    from proteus.game.runtime.memory_gen import generate_memory
 
     agent = _agent()
     generate_memory(
diff --git a/tests/runtime/test_memory_persona.py b/tests/runtime/test_memory_persona.py
index 4a880b8d0caa7562c38768e3dd3cce736f77fa10..a0f0d1f1db3e04ea0eef743e08ab8e0bcb79afc5 100644
--- a/tests/runtime/test_memory_persona.py
+++ b/tests/runtime/test_memory_persona.py
@@ -1,6 +1,6 @@
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime.memory_gen import generate_memory
-from proteus.runtime.persona import PersonaWeights
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime.memory_gen import generate_memory
+from proteus.game.metrics.persona import PersonaWeights
 
 
 def test_persona_memory_is_deterministic_and_tags_persona():
diff --git a/tests/runtime/test_memory_policies.py b/tests/runtime/test_memory_policies.py
index 9281ef737907f3d0f2d2ed1e23550d7af2461727..fcce760d1a54daad56a7ab470d7cfbb46ea0572a 100644
--- a/tests/runtime/test_memory_policies.py
+++ b/tests/runtime/test_memory_policies.py
@@ -1,10 +1,10 @@
 """Scripted memory policies produce distinct, on-motive 100-turn trajectories."""
 from __future__ import annotations
 
-import proteus.grid  # noqa: F401  (registers scenarios)
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime.memory_gen import generate_memory
-from proteus.runtime.memory_policies import (
+import proteus.game.scenarios  # noqa: F401  (registers scenarios)
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime.memory_gen import generate_memory
+from proteus.game.runtime.memory_policies import (
     available_policies, get_policy,
 )
 
diff --git a/tests/runtime/test_metrics.py b/tests/runtime/test_metrics.py
index 3d512a994ec406a6a1393b8053cbf234cc6a79bd..998e8e1fd6d40ec95c0c0af290aa08ef529967dc 100644
--- a/tests/runtime/test_metrics.py
+++ b/tests/runtime/test_metrics.py
@@ -1,5 +1,5 @@
-from proteus.runtime.trace import TurnTrace, SessionTrace
-from proteus.runtime.metrics import compute_metrics
+from proteus.game.runtime.trace import TurnTrace, SessionTrace
+from proteus.game.metrics.metrics import compute_metrics
 
 
 def _turn(idx, action, motive, habit, reward, focal_pos=(0, 0)):
@@ -142,8 +142,8 @@ def test_trajectory_agreement_penalizes_turns_beyond_optimal():
 
 
 def test_distance_metrics_present_and_sane():
-    from proteus.runtime.metrics import compute_metrics
-    from proteus.runtime.trace import TurnTrace
+    from proteus.game.metrics.metrics import compute_metrics
+    from proteus.game.runtime.trace import TurnTrace
 
     turns = [
         TurnTrace(turn_idx=i, observation="", action="up", motive_action="up",
diff --git a/tests/runtime/test_pack_evade_memory.py b/tests/runtime/test_pack_evade_memory.py
index a99bcadbdc14e805017d6177c6d8e6cdec38c251..c2291b612b0e9e8e64dd1ca93f95c47bbfb837b3 100644
--- a/tests/runtime/test_pack_evade_memory.py
+++ b/tests/runtime/test_pack_evade_memory.py
@@ -4,12 +4,12 @@ design (docs/agentness_game_design_from_paper.md §3-4). The raw weights never
 leak; only the public persona_weight_id + the behaviour trajectory are stored."""
 from __future__ import annotations
 
-import proteus.grid  # noqa: F401
-from proteus.agents.human import HumanAgent
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.scenario import get_scenario
-from proteus.runtime.memory import MemoryCheckpoint
-from proteus.runtime.session import SessionRunner
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.agents.human import HumanAgent
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.scenarios.base import get_scenario
+from proteus.game.runtime.memory import MemoryCheckpoint
+from proteus.game.runtime.session import SessionRunner
 
 
 def test_default_memory_is_persona_generated():
diff --git a/tests/runtime/test_persona.py b/tests/runtime/test_persona.py
index 2d1024fd8a30c43dd02c10e9c290bc71357a5176..bd30d1aa4a65043b2c69bd04a68521efdd362d01 100644
--- a/tests/runtime/test_persona.py
+++ b/tests/runtime/test_persona.py
@@ -1,9 +1,9 @@
 import random
-import proteus.grid  # noqa: F401
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.game import MotiveGridGame
-from proteus.grid.scenario import get_scenario
-from proteus.runtime.persona import PersonaWeights, reference_actions, pressure
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
+from proteus.game.metrics.persona import PersonaWeights, reference_actions, pressure
 
 
 def _sg():
@@ -34,9 +34,9 @@ def test_pressure_in_unit_range():
 
 def _runner(action, persona_id="risk_averse", play_turns=1):
     from proteus.providers import FakeProvider
-    from proteus.agents import VanillaAgent
-    from proteus.runtime import SessionRunner
-    from proteus.runtime.persona import get_persona
+    from proteus.game.agents import VanillaAgent
+    from proteus.game.runtime import SessionRunner
+    from proteus.game.metrics.persona import get_persona
     prov = FakeProvider([f"ACTION: {action}"] * 10, model_name="demo")
     return SessionRunner(
         "predator_evade", VanillaAgent(prov), difficulty=Difficulty.EASY,
@@ -70,8 +70,8 @@ def test_into_wall_lowers_agreement_and_positive_regret():
 
 def test_persona_metrics_absent_without_persona():
     from proteus.providers import FakeProvider
-    from proteus.agents import VanillaAgent
-    from proteus.runtime import SessionRunner
+    from proteus.game.agents import VanillaAgent
+    from proteus.game.runtime import SessionRunner
     prov = FakeProvider(["ACTION: up"] * 10, model_name="demo")
     m = SessionRunner(
         "predator_evade", VanillaAgent(prov), difficulty=Difficulty.EASY,
diff --git a/tests/runtime/test_rollout.py b/tests/runtime/test_rollout.py
index dadc76ea24a397f0594eaad92e6008e2671954af..23d6074a12569d950fa8a4afebf0d77059c3fd8f 100644
--- a/tests/runtime/test_rollout.py
+++ b/tests/runtime/test_rollout.py
@@ -1,5 +1,5 @@
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime.rollout import RolloutResult, optimal_rollout
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.metrics.rollout import RolloutResult, optimal_rollout
 
 
 def test_optimal_rollout_is_deterministic():
diff --git a/tests/runtime/test_session.py b/tests/runtime/test_session.py
index f7163bf8a711eae0b54d7aab0e7ed9e32647768e..7804175c4e3993ae64c8b8ca80fc6c02e7034061 100644
--- a/tests/runtime/test_session.py
+++ b/tests/runtime/test_session.py
@@ -1,7 +1,7 @@
 from proteus.providers import FakeProvider
-from proteus.agents import VanillaAgent
-from proteus.runtime.session import SessionRunner
-from proteus.runtime.trace import SessionTrace
+from proteus.game.agents import VanillaAgent
+from proteus.game.runtime.session import SessionRunner
+from proteus.game.runtime.trace import SessionTrace
 
 
 def _agent(responses):
diff --git a/tests/runtime/test_session_core.py b/tests/runtime/test_session_core.py
index 72827220d8c1b9aafe46ac853662d0301726f2ee..fafb4b1db263694f30cec713b3f8b3edb4d2dd2a 100644
--- a/tests/runtime/test_session_core.py
+++ b/tests/runtime/test_session_core.py
@@ -4,9 +4,9 @@ from __future__ import annotations
 
 import pytest
 
-import proteus.grid  # noqa: F401  (registers predator_evade)
-from proteus.grid.difficulty import Difficulty
-from proteus.runtime import _session_core as core
+import proteus.game.scenarios  # noqa: F401  (registers predator_evade)
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.runtime import _session_core as core
 
 
 def test_build_session_is_deterministic_and_non_terminal():
diff --git a/tests/runtime/test_session_distance.py b/tests/runtime/test_session_distance.py
index 4e9a2af9a44c178e1e3a3ba1a12d9f0abe7d32f6..3c7482dcfa3f2c0a6da24120a5877edb9c0972bf 100644
--- a/tests/runtime/test_session_distance.py
+++ b/tests/runtime/test_session_distance.py
@@ -1,8 +1,8 @@
-import proteus.grid  # noqa: F401
-from proteus.grid.difficulty import Difficulty
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.engine.difficulty import Difficulty
 from proteus.providers import FakeProvider
-from proteus.agents import VanillaAgent
-from proteus.runtime import SessionRunner
+from proteus.game.agents import VanillaAgent
+from proteus.game.runtime import SessionRunner
 
 
 def test_each_turn_records_pre_and_post_bfs_distance():
diff --git a/tests/runtime/test_session_memory.py b/tests/runtime/test_session_memory.py
index b1ef7423d4688cca143259debfae81629a692da1..0e97d430e24ca40f27723e44d6b4433254fbdb85 100644
--- a/tests/runtime/test_session_memory.py
+++ b/tests/runtime/test_session_memory.py
@@ -1,4 +1,4 @@
-from proteus.runtime.trace import SessionTrace
+from proteus.game.runtime.trace import SessionTrace
 
 
 def test_session_trace_memory_ref_defaults_none_and_round_trips():
@@ -18,11 +18,11 @@ def test_session_trace_memory_ref_defaults_none_and_round_trips():
     assert SessionTrace.model_validate_json(t3.model_dump_json()).memory_ref == "demo@FIXED"
 
 
-from proteus.agents import VanillaAgent
-from proteus.grid.difficulty import Difficulty
+from proteus.game.agents import VanillaAgent
+from proteus.game.engine.difficulty import Difficulty
 from proteus.providers import FakeProvider
-from proteus.runtime import SessionRunner
-from proteus.runtime.memory import MemoryCheckpoint, MemoryTurn
+from proteus.game.runtime import SessionRunner
+from proteus.game.runtime.memory import MemoryCheckpoint, MemoryTurn
 
 
 def _memory() -> MemoryCheckpoint:
diff --git a/tests/runtime/test_spectate.py b/tests/runtime/test_spectate.py
index 00d6f9fb4e03913f36e717f288368d596a6d075f..c4a57a6b421c479de8bce557e835ff1a6b15cd25 100644
--- a/tests/runtime/test_spectate.py
+++ b/tests/runtime/test_spectate.py
@@ -3,12 +3,12 @@ from __future__ import annotations
 
 import pytest
 
-import proteus.grid  # noqa: F401
-from proteus.agents.vanilla import VanillaAgent
-from proteus.grid.difficulty import Difficulty
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.agents.vanilla import VanillaAgent
+from proteus.game.engine.difficulty import Difficulty
 from proteus.providers.fake import FakeProvider
-from proteus.runtime._session_core import SessionFinishedError
-from proteus.runtime.spectate import SpectateSession
+from proteus.game.runtime._session_core import SessionFinishedError
+from proteus.game.runtime.spectate import SpectateSession
 
 
 def _agent(n=10):
diff --git a/tests/runtime/test_spectate_equivalence.py b/tests/runtime/test_spectate_equivalence.py
index 8e99e9b74d4df69b7bf2774a9ff6447036462bc5..8847a9242a00cc0dff000181fcf3d31a867f6712 100644
--- a/tests/runtime/test_spectate_equivalence.py
+++ b/tests/runtime/test_spectate_equivalence.py
@@ -3,12 +3,12 @@ whether driven through SpectateSession (one advance per turn) or SessionRunner +
 VanillaAgent (batch). Pins the spectate path to the runner path."""
 from __future__ import annotations
 
-import proteus.grid  # noqa: F401
-from proteus.agents.vanilla import VanillaAgent
-from proteus.grid.difficulty import Difficulty
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.agents.vanilla import VanillaAgent
+from proteus.game.engine.difficulty import Difficulty
 from proteus.providers.fake import FakeProvider
-from proteus.runtime.session import SessionRunner
-from proteus.runtime.spectate import SpectateSession
+from proteus.game.runtime.session import SessionRunner
+from proteus.game.runtime.spectate import SpectateSession
 
 RESPONSES = ["ACTION: up", "ACTION: up", "ACTION: left",
              "ACTION: stay", "ACTION: right", "ACTION: up"]
diff --git a/tests/runtime/test_trace.py b/tests/runtime/test_trace.py
index b7b00f85e5c186e99160493935344eaf2fa28a2a..3c9a70d8ff1cb74261afd0d23d6073dbf10ce9a5 100644
--- a/tests/runtime/test_trace.py
+++ b/tests/runtime/test_trace.py
@@ -1,4 +1,4 @@
-from proteus.runtime.trace import TurnTrace, SessionTrace
+from proteus.game.runtime.trace import TurnTrace, SessionTrace
 
 
 def test_turntrace_roundtrips_json():
@@ -56,7 +56,7 @@ def test_sessiontrace_defaults_and_nesting():
 
 
 def test_turntrace_distance_fields_default_none_and_round_trip():
-    from proteus.runtime.trace import TurnTrace
+    from proteus.game.runtime.trace import TurnTrace
     t = TurnTrace(
         turn_idx=1, observation="o", action="up", motive_action="up",
         habit_action="left", is_diagnostic=True, was_congruent=True,
diff --git a/tests/runtime/test_trace_accounting.py b/tests/runtime/test_trace_accounting.py
index 708429338942fbd640352ab22d1ef4eed6b503fd..6a6db512e853789675f27458ca7048958ec550a5 100644
--- a/tests/runtime/test_trace_accounting.py
+++ b/tests/runtime/test_trace_accounting.py
@@ -1,6 +1,6 @@
-from proteus.agents import VanillaAgent
+from proteus.game.agents import VanillaAgent
 from proteus.providers import FakeProvider
-from proteus.runtime import SessionRunner, SessionTrace
+from proteus.game.runtime import SessionRunner, SessionTrace
 
 
 def _run(response):
diff --git a/tests/test_arc_grid_vendored.py b/tests/test_arc_grid_vendored.py
index d4fa87edfec125e67ba762310fb67579e81b4bc3..ede2fc751bd5d921fa0e613b54e6f97b003eb997 100644
--- a/tests/test_arc_grid_vendored.py
+++ b/tests/test_arc_grid_vendored.py
@@ -1,5 +1,5 @@
 def test_arc_grid_engine_surface_importable():
-    from proteus.arc_grid import Sprite, Level, Camera, ARCBaseGame, GameAction
+    from proteus.game.engine import Sprite, Level, Camera, ARCBaseGame, GameAction
     sprite = Sprite(pixels=[[1]], name="x", x=0, y=0)
     assert sprite.x == 0 and sprite.y == 0
 
diff --git a/tests/viz/test_gif.py b/tests/viz/test_gif.py
index 410f4bf9332ac734a4ddc11282be1197eb4837cb..f031710a73ffd8ff6d49b3d77ad9f238d59badc8 100644
--- a/tests/viz/test_gif.py
+++ b/tests/viz/test_gif.py
@@ -1,9 +1,9 @@
-import proteus.grid  # noqa: F401
-from proteus.grid.difficulty import Difficulty
+import proteus.game.scenarios  # noqa: F401
+from proteus.game.engine.difficulty import Difficulty
 from proteus.providers import FakeProvider
-from proteus.agents import VanillaAgent
-from proteus.runtime import SessionRunner
-from proteus.viz import reconstruct, write_gif
+from proteus.game.agents import VanillaAgent
+from proteus.game.runtime import SessionRunner
+from proteus.game.viz import reconstruct, write_gif
 
 
 def _trace():
diff --git a/tests/viz/test_import_safety.py b/tests/viz/test_import_safety.py
index 279775143fa2b7c10b8ac2d04c62f1749b83ebdd..98545b2d6477d93f2f183e4546630de82b223028 100644
--- a/tests/viz/test_import_safety.py
+++ b/tests/viz/test_import_safety.py
@@ -7,11 +7,11 @@ def test_importing_viz_does_not_import_matplotlib():
         if name == "matplotlib" or name.startswith("matplotlib."):
             del sys.modules[name]
     for name in list(sys.modules):
-        if name == "proteus.viz" or name.startswith("proteus.viz."):
+        if name == "proteus.game.viz" or name.startswith("proteus.game.viz."):
             del sys.modules[name]
 
-    import proteus.viz  # noqa: F401
+    import proteus.game.viz  # noqa: F401
 
     assert "matplotlib" not in sys.modules, (
-        "importing proteus.viz pulled in matplotlib; keep it lazy in write_pngs"
+        "importing proteus.game.viz pulled in matplotlib; keep it lazy in write_pngs"
     )
diff --git a/tests/viz/test_png.py b/tests/viz/test_png.py
index 24872eccc87c03c0583bec262693b2a25da0b471..eb518b427e78bba13855e19e90769a31f080a30a 100644
--- a/tests/viz/test_png.py
+++ b/tests/viz/test_png.py
@@ -2,10 +2,10 @@ import pytest
 
 pytest.importorskip("matplotlib")  # PNG path needs the `viz` extra
 
-from proteus.agents import VanillaAgent
+from proteus.game.agents import VanillaAgent
 from proteus.providers import FakeProvider
-from proteus.runtime.session import SessionRunner
-from proteus.viz import reconstruct, write_pngs
+from proteus.game.runtime.session import SessionRunner
+from proteus.game.viz import reconstruct, write_pngs
 
 
 def _steps():
@@ -36,8 +36,8 @@ def test_write_pngs_creates_missing_dir(tmp_path):
     assert len(paths) == len(steps)
 
 
-from proteus.viz.png import _title
-from proteus.viz.reconstruct import FrameMeta, FrameStep
+from proteus.game.viz.png import _title
+from proteus.game.viz.reconstruct import FrameMeta, FrameStep
 import numpy as np
 
 
diff --git a/tests/viz/test_reconstruct.py b/tests/viz/test_reconstruct.py
index 47ed6b49c00eaf0ac2390ce6c028e0371074c37f..21f1458dfcc0b8fdfc80547ea8ab26fef2367fcc 100644
--- a/tests/viz/test_reconstruct.py
+++ b/tests/viz/test_reconstruct.py
@@ -1,12 +1,12 @@
 import numpy as np
 import pytest
 
-from proteus.agents import VanillaAgent
-from proteus.grid.difficulty import Difficulty
-from proteus.grid.scenario import get_scenario
+from proteus.game.agents import VanillaAgent
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.scenarios.base import get_scenario
 from proteus.providers import FakeProvider
-from proteus.runtime.session import SessionRunner
-from proteus.viz import FrameStep, TraceReconstructionError, reconstruct
+from proteus.game.runtime.session import SessionRunner
+from proteus.game.viz import FrameStep, TraceReconstructionError, reconstruct
 
 
 def _make_trace(seed=42, turns=5, action="ACTION: up"):
diff --git a/tests/viz/test_terminal.py b/tests/viz/test_terminal.py
index d19605016b67ef186b111c5831583404721c08aa..71eeec58f7469883efdaf691d519898d5e3f22de 100644
--- a/tests/viz/test_terminal.py
+++ b/tests/viz/test_terminal.py
@@ -1,7 +1,7 @@
-from proteus.agents import VanillaAgent
+from proteus.game.agents import VanillaAgent
 from proteus.providers import FakeProvider
-from proteus.runtime.session import SessionRunner
-from proteus.viz import reconstruct, render_terminal
+from proteus.game.runtime.session import SessionRunner
+from proteus.game.viz import reconstruct, render_terminal
 
 
 def _steps():
@@ -34,6 +34,6 @@ def test_render_terminal_emits_truecolor_and_panel_fields():
 def test_render_terminal_does_not_sleep(monkeypatch):
     steps, _ = _steps()
     calls = []
-    monkeypatch.setattr("proteus.viz.terminal.time.sleep", lambda s: calls.append(s))
+    monkeypatch.setattr("proteus.game.viz.terminal.time.sleep", lambda s: calls.append(s))
     render_terminal(steps, fps=0, writer=lambda s: None)
     assert calls == []  # fps=0 computes delay=0.0 -> sleep never called
diff --git a/tests/web/test_import_safety.py b/tests/web/test_import_safety.py
index f9cb4c18631f993afc6be08b1d3b0079fb09d45a..e63596e7c6c5b141a5714b899a5e92df809c7ce1 100644
--- a/tests/web/test_import_safety.py
+++ b/tests/web/test_import_safety.py
@@ -6,29 +6,29 @@ import sys
 
 
 def test_importing_web_pulls_no_heavy_or_network_deps():
-    # Drop any pre-loaded matplotlib and proteus.web so we observe a fresh
+    # Drop any pre-loaded matplotlib and proteus.web.local so we observe a fresh
     # import graph even when earlier tests have cached these modules.
     for mod in list(sys.modules):
         if mod == "matplotlib" or mod.startswith("matplotlib."):
             del sys.modules[mod]
     for mod in list(sys.modules):
-        if mod == "proteus.web" or mod.startswith("proteus.web."):
+        if mod == "proteus.web.local" or mod.startswith("proteus.web.local."):
             del sys.modules[mod]
 
-    import proteus.web            # noqa: F401
-    import proteus.web.server     # noqa: F401
+    import proteus.web.local            # noqa: F401
+    import proteus.web.local.server     # noqa: F401
 
     assert "matplotlib" not in sys.modules, (
-        "importing proteus.web pulled in matplotlib; keep the web layer offline"
+        "importing proteus.web.local pulled in matplotlib; keep the web layer offline"
     )
     # provider SDKs are never imported by the web layer
     for sdk in ("openai", "anthropic", "google", "ollama"):
         assert sdk not in sys.modules, (
-            f"importing proteus.web pulled in provider SDK {sdk!r}"
+            f"importing proteus.web.local pulled in provider SDK {sdk!r}"
         )
 
     # spectate routes import providers LAZILY (inside the handler), so a plain
     # import of the web layer must still pull no provider SDK.
-    import proteus.web.server  # noqa: F401  (re-exercised after the clear above)
+    import proteus.web.local.server  # noqa: F401  (re-exercised after the clear above)
     for sdk in ("openai", "anthropic", "google", "ollama"):
         assert sdk not in sys.modules
diff --git a/tests/web/test_memory_modes.py b/tests/web/test_memory_modes.py
index cff4a7d6f8f050f210b02344f8d1f1a2ec8445fc..d9cebe836bb5ad454aa5e6e9edf3322870b012be 100644
--- a/tests/web/test_memory_modes.py
+++ b/tests/web/test_memory_modes.py
@@ -2,8 +2,8 @@
 default / none / persona[:id] / generate / latest, plus the raised action quota."""
 from __future__ import annotations
 
-import proteus.grid  # noqa: F401
-from proteus.web import server
+import proteus.game.scenarios  # noqa: F401
+from proteus.web.local import server
 
 
 def _reg():
diff --git a/tests/web/test_server.py b/tests/web/test_server.py
index dd8395ecc9bbc97af615392301c07d9f77486636..3dd65a5f20a6be9b1ddb55498cf4d43cad3d767e 100644
--- a/tests/web/test_server.py
+++ b/tests/web/test_server.py
@@ -3,8 +3,8 @@ from __future__ import annotations
 
 import json
 
-import proteus.grid  # noqa: F401
-from proteus.web import server
+import proteus.game.scenarios  # noqa: F401
+from proteus.web.local import server
 
 
 def _registry():
diff --git a/tests/web/test_spectate_routes.py b/tests/web/test_spectate_routes.py
index 655ba4e811149e3ff1634057973776ca1bd13381..8aff5d9c0c6def336b1468875c18c121adc22a95 100644
--- a/tests/web/test_spectate_routes.py
+++ b/tests/web/test_spectate_routes.py
@@ -1,8 +1,8 @@
 """Route-level tests for spectating (offline via fake:demo, no socket)."""
 from __future__ import annotations
 
-import proteus.grid  # noqa: F401
-from proteus.web import server
+import proteus.game.scenarios  # noqa: F401
+from proteus.web.local import server
 
 
 def _reg():