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+# Phase L.2g slice 1 — Dynamic PhysicsState Toggling Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Spec:** [docs/superpowers/specs/2026-05-12-l2g-dynamic-physicsstate-design.md](../specs/2026-05-12-l2g-dynamic-physicsstate-design.md) (committed in `2c10dd4`).
+**Branch:** `claude/gallant-mestorf-3bf2e3` (do all commits here; user merges to main separately).
+
+**Goal:** Parse inbound `GameMessageSetState (opcode 0xF74B)` and propagate
+the new `PhysicsState` value into `ShadowObjectRegistry`'s cached per-entity
+record so the existing `CollisionExemption.IsExempt(...)` short-circuit honors
+runtime ETHEREAL flips — unblocking the M1 demo's *"open the inn door"* line.
+
+**Architecture:** One new wire-message parser (`SetState`), one new event on
+`WorldSession`, one new mutator method on `ShadowObjectRegistry`
+(`UpdatePhysicsState`), one new subscriber in `GameWindow`. **No resolver
+changes.** The existing `CollisionExemption.cs` short-circuit (cited at
+`acclient_2013_pseudo_c.txt:276782`) already handles ETHEREAL; slice 1 just
+feeds it fresh data.
+
+**Tech Stack:** C# .NET 10, xUnit for tests, BinaryPrimitives for
+little-endian reads. Mirror the existing `VectorUpdate.cs` parser pattern.
+
+**Retail anchor (port reference):** `CPhysicsObj::set_state` at
+`docs/research/named-retail/acclient_2013_pseudo_c.txt:283044`. The retail
+implementation: `this->state = arg2` (line 283048) plus three side-effect
+handlers for the changed-bit set (`0x800` lighting, `0x20` nodraw, `0x4000`
+hidden). **Slice 1 ports only the state-store half**; ETHEREAL (`0x4`) is
+not in the side-effect set, so the cosmetic handlers are not on the
+M1-critical path and stay deferred.
+
+---
+
+## File Structure
+
+| File | Action | Responsibility |
+|---|---|---|
+| `src/AcDream.Core.Net/Messages/SetState.cs` | Create | New inbound DTO + `TryParse` for opcode `0xF74B`. Mirrors `VectorUpdate.cs`. |
+| `src/AcDream.Core.Net/WorldSession.cs` | Modify | Add `StateUpdated` event + dispatch branch for `op == SetState.Opcode`. |
+| `src/AcDream.Core/Physics/ShadowObjectRegistry.cs` | Modify | Add `UpdatePhysicsState(uint, uint)` method that mutates the cached `ShadowEntry.State` in every cell the entity occupies. |
+| `src/AcDream.App/Rendering/GameWindow.cs` | Modify | Subscribe to `_liveSession.StateUpdated`, route `(guid, newState)` to `_physicsEngine.ShadowObjects.UpdatePhysicsState(...)`. Extend `[entity-source]` log with `state=` + `flags=` (slice 0.5 freebie). |
+| `tests/AcDream.Core.Net.Tests/Messages/SetStateTests.cs` | Create | TryParse byte-level tests (well-formed, truncated, opcode-mismatch). |
+| `tests/AcDream.Core.Tests/Physics/ShadowObjectRegistryTests.cs` | Modify | Add `UpdatePhysicsState_FlipsEthereal_NextLookupExempt` test using `CollisionExemption.ShouldSkip`. |
+
+**No new project references needed** — all files live in existing assemblies.
+
+---
+
+## Task 1: Parser DTO + TryParse for `SetState` (opcode `0xF74B`)
+
+**Files:**
+- Create: `src/AcDream.Core.Net/Messages/SetState.cs`
+- Create: `tests/AcDream.Core.Net.Tests/Messages/SetStateTests.cs`
+
+**Reference template:** `src/AcDream.Core.Net/Messages/VectorUpdate.cs`
+(read it before writing — same opcode dispatch convention, same body-length
+check shape, same `BinaryPrimitives` style).
+
+**Wire format** (per
+`references/holtburger/crates/holtburger-protocol/src/messages/object/messages/properties.rs:117-122`,
+matched by every other acdream parser):
+
+```
+offset 0 : u32 opcode (= 0xF74B)
+offset 4 : u32 guid
+offset 8 : u32 physics_state (bitmask; ETHEREAL = 0x4)
+offset 12 : u16 instance_sequence
+offset 14 : u16 state_sequence
+Total: 16 bytes from start of body.
+```
+
+- [ ] **Step 1.1: Write the failing TryParse tests**
+
+Create `tests/AcDream.Core.Net.Tests/Messages/SetStateTests.cs` with:
+
+```csharp
+using System;
+using System.Buffers.Binary;
+using AcDream.Core.Net.Messages;
+using Xunit;
+
+namespace AcDream.Core.Net.Tests.Messages;
+
+public class SetStateTests
+{
+ [Fact]
+ public void TryParse_WellFormedBody_ReturnsParsed()
+ {
+ // Build a synthetic SetState body: opcode + guid + state + 2×u16 seq.
+ var buf = new byte[16];
+ BinaryPrimitives.WriteUInt32LittleEndian(buf.AsSpan(0, 4), 0xF74Bu);
+ BinaryPrimitives.WriteUInt32LittleEndian(buf.AsSpan(4, 4), 0x000F4244u); // door guid
+ BinaryPrimitives.WriteUInt32LittleEndian(buf.AsSpan(8, 4), 0x00000004u); // ETHEREAL bit
+ BinaryPrimitives.WriteUInt16LittleEndian(buf.AsSpan(12, 2), (ushort)355);
+ BinaryPrimitives.WriteUInt16LittleEndian(buf.AsSpan(14, 2), (ushort)42);
+
+ var parsed = SetState.TryParse(buf);
+
+ Assert.NotNull(parsed);
+ Assert.Equal(0x000F4244u, parsed.Value.Guid);
+ Assert.Equal(0x00000004u, parsed.Value.PhysicsState);
+ Assert.Equal((ushort)355, parsed.Value.InstanceSequence);
+ Assert.Equal((ushort)42, parsed.Value.StateSequence);
+ }
+
+ [Fact]
+ public void TryParse_Truncated_ReturnsNull()
+ {
+ var buf = new byte[10]; // < 16 bytes
+ Assert.Null(SetState.TryParse(buf));
+ }
+
+ [Fact]
+ public void TryParse_WrongOpcode_ReturnsNull()
+ {
+ var buf = new byte[16];
+ BinaryPrimitives.WriteUInt32LittleEndian(buf.AsSpan(0, 4), 0xF74Cu); // UpdateMotion, not SetState
+ Assert.Null(SetState.TryParse(buf));
+ }
+}
+```
+
+- [ ] **Step 1.2: Run tests to verify they fail (RED)**
+
+Run: `dotnet test tests/AcDream.Core.Net.Tests/AcDream.Core.Net.Tests.csproj --filter "FullyQualifiedName~SetStateTests"`
+Expected: Compile error — `SetState` type not defined.
+
+- [ ] **Step 1.3: Write the parser**
+
+Create `src/AcDream.Core.Net/Messages/SetState.cs`:
+
+```csharp
+using System;
+using System.Buffers.Binary;
+
+namespace AcDream.Core.Net.Messages;
+
+///
+/// Inbound SetState GameMessage (opcode 0xF74B). The server
+/// broadcasts this whenever a previously-spawned entity's
+/// PhysicsState bitmask changes after CreateObject — chiefly
+/// when a door opens / closes (server flips ETHEREAL_PS = 0x4) or a
+/// spell projectile becomes ethereal post-impact.
+///
+///
+/// Wire layout (per
+/// references/holtburger/crates/holtburger-protocol/src/messages/object/messages/properties.rs:117-122,
+/// matched by every other acdream parser):
+///
+///
+/// - u32 opcode — 0xF74B
+/// - u32 objectGuid
+/// - u32 physicsState — bitmask (acclient.h:2815 / 2819)
+/// - u16 instanceSequence — stale-packet rejection
+/// - u16 stateSequence — stale-packet rejection
+///
+///
+///
+/// Total body size: 16 bytes from start (opcode + 12-byte payload).
+///
+///
+///
+/// Server-side reference:
+/// references/ACE/Source/ACE.Server/Network/GameMessages/Messages/GameMessageSetState.cs:8-15
+/// (ACE writes the same field order but appears to use uint for the
+/// sequence fields; verified against retail format by hex-dump probe in
+/// Task 5). Holtburger has been validated against a retail-format server,
+/// so its 12-byte payload is the trusted spec.
+///
+///
+public static class SetState
+{
+ public const uint Opcode = 0xF74Bu;
+
+ public readonly record struct Parsed(
+ uint Guid,
+ uint PhysicsState,
+ ushort InstanceSequence,
+ ushort StateSequence);
+
+ ///
+ /// Parse a 0xF74B body. must start with the
+ /// 4-byte opcode (matches the convention used by VectorUpdate /
+ /// UpdateMotion / UpdatePosition). Returns null on truncation or
+ /// opcode mismatch.
+ ///
+ public static Parsed? TryParse(ReadOnlySpan body)
+ {
+ if (body.Length < 16) return null;
+ try
+ {
+ uint opcode = BinaryPrimitives.ReadUInt32LittleEndian(body.Slice(0, 4));
+ if (opcode != Opcode) return null;
+
+ uint guid = BinaryPrimitives.ReadUInt32LittleEndian(body.Slice(4, 4));
+ uint state = BinaryPrimitives.ReadUInt32LittleEndian(body.Slice(8, 4));
+ ushort instSeq = BinaryPrimitives.ReadUInt16LittleEndian(body.Slice(12, 2));
+ ushort stateSeq = BinaryPrimitives.ReadUInt16LittleEndian(body.Slice(14, 2));
+
+ return new Parsed(guid, state, instSeq, stateSeq);
+ }
+ catch
+ {
+ return null;
+ }
+ }
+}
+```
+
+- [ ] **Step 1.4: Run tests to verify they pass (GREEN)**
+
+Run: `dotnet test tests/AcDream.Core.Net.Tests/AcDream.Core.Net.Tests.csproj --filter "FullyQualifiedName~SetStateTests"`
+Expected: 3 passed.
+
+- [ ] **Step 1.5: Verify project build still green**
+
+Run: `dotnet build`
+Expected: Build succeeded, 0 errors, 0 new warnings.
+
+- [ ] **Step 1.6: Commit**
+
+```
+git add src/AcDream.Core.Net/Messages/SetState.cs tests/AcDream.Core.Net.Tests/Messages/SetStateTests.cs
+git commit -m "feat(phys L.2g slice 1): inbound SetState (0xF74B) parser
+
+DTO + TryParse for the GameMessageSetState wire message. The server
+broadcasts this when an already-spawned entity's PhysicsState changes
+post-CreateObject — chiefly when a door's Ethereal bit toggles on Use.
+
+Wire format per holtburger SetStateData (validated against retail-format
+servers): u32 opcode + u32 guid + u32 state + u16 instanceSequence + u16
+stateSequence = 16 bytes total. Mirrors the existing VectorUpdate.cs
+template.
+
+Co-Authored-By: Claude Opus 4.7 (1M context) "
+```
+
+---
+
+## Task 2: `ShadowObjectRegistry.UpdatePhysicsState(guid, newState)`
+
+**Files:**
+- Modify: `src/AcDream.Core/Physics/ShadowObjectRegistry.cs` (add new method after `UpdatePosition`, before `Deregister`)
+- Modify: `tests/AcDream.Core.Tests/Physics/ShadowObjectRegistryTests.cs` (append new test)
+
+**Design rationale:** `ShadowEntry` is a `readonly record struct` (value type)
+stored as copies inside per-cell `List`. Mutation pattern:
+find every cell the entity occupies via `_entityToCells[entityId]`, then
+replace each in-list copy with `list[i] = list[i] with { State = newState }`.
+
+**Retail anchor:** `CPhysicsObj::set_state` at
+`docs/research/named-retail/acclient_2013_pseudo_c.txt:283044`. Retail
+does `this->state = arg2` (line 283048) — direct overwrite. Our cached
+state lives in the registry copy, not the entity, so the equivalent is
+"overwrite every shadow copy."
+
+- [ ] **Step 2.1: Write the failing test**
+
+Append to `tests/AcDream.Core.Tests/Physics/ShadowObjectRegistryTests.cs`
+(top-of-file using directives already have `AcDream.Core.Physics` + xUnit):
+
+```csharp
+ // -----------------------------------------------------------------------
+ // UpdatePhysicsState — L.2g slice 1 (doors flip ETHEREAL post-spawn)
+ // -----------------------------------------------------------------------
+
+ [Fact]
+ public void UpdatePhysicsState_FlipsEthereal_NextLookupSeesNewBits()
+ {
+ // Register a door-like entity with State=0 (closed = solid).
+ var reg = new ShadowObjectRegistry();
+ const uint doorId = 0x000F4244u;
+ reg.Register(doorId, 0x020019FFu, new Vector3(12f, 12f, 50f),
+ Quaternion.Identity, 1f, OffX, OffY, LbId,
+ state: 0u, flags: EntityCollisionFlags.None);
+
+ // Sanity: cached state starts at 0 (no ETHEREAL).
+ var before = reg.AllEntriesForDebug().Single(e => e.EntityId == doorId);
+ Assert.Equal(0u, before.State);
+
+ // Flip ETHEREAL_PS (0x4) — the server's "door is now open" message.
+ reg.UpdatePhysicsState(doorId, 0x00000004u);
+
+ // Cached state should now show the new bit.
+ var after = reg.AllEntriesForDebug().Single(e => e.EntityId == doorId);
+ Assert.Equal(0x00000004u, after.State);
+ }
+
+ [Fact]
+ public void UpdatePhysicsState_UnregisteredEntity_IsNoOp()
+ {
+ var reg = new ShadowObjectRegistry();
+ // No entity registered. Should not throw.
+ reg.UpdatePhysicsState(0xDEADBEEFu, 0x00000004u);
+ Assert.Equal(0, reg.TotalRegistered);
+ }
+
+ [Fact]
+ public void UpdatePhysicsState_EntitySpanningMultipleCells_AllCellsUpdated()
+ {
+ // Entity at (24,12) with radius=2 spans cells (0,0) and (1,0).
+ var reg = new ShadowObjectRegistry();
+ reg.Register(99u, 0x01000099u, new Vector3(24f, 12f, 50f),
+ Quaternion.Identity, 2f, OffX, OffY, LbId,
+ state: 0u);
+
+ reg.UpdatePhysicsState(99u, 0x00000004u);
+
+ uint cellA = LbId | 1u; // cx=0
+ uint cellB = LbId | (1u*8 + 0 + 1); // cx=1
+ var inA = reg.GetObjectsInCell(cellA).Single(e => e.EntityId == 99u);
+ var inB = reg.GetObjectsInCell(cellB).Single(e => e.EntityId == 99u);
+ Assert.Equal(0x00000004u, inA.State);
+ Assert.Equal(0x00000004u, inB.State);
+ }
+```
+
+You may need a `using System.Linq;` at the top of the test file. Add it if
+not already present.
+
+- [ ] **Step 2.2: Run tests to verify they fail (RED)**
+
+Run: `dotnet test tests/AcDream.Core.Tests/AcDream.Core.Tests.csproj --filter "FullyQualifiedName~UpdatePhysicsState"`
+Expected: Compile error — `UpdatePhysicsState` method not defined.
+
+- [ ] **Step 2.3: Implement `UpdatePhysicsState`**
+
+Insert into `src/AcDream.Core/Physics/ShadowObjectRegistry.cs` after the
+`UpdatePosition` method (around line 127, before the `Deregister` summary
+comment):
+
+```csharp
+ ///
+ /// Update the cached bits for an
+ /// already-registered entity. Called by the inbound
+ /// SetState (0xF74B) dispatcher when the server broadcasts a
+ /// post-spawn PhysicsState change — chiefly doors flipping
+ /// ETHEREAL_PS = 0x4 on Use, so the
+ /// short-circuit can honor
+ /// the new state on the next resolve.
+ ///
+ ///
+ /// Retail equivalent: CPhysicsObj::set_state at
+ /// docs/research/named-retail/acclient_2013_pseudo_c.txt:283044
+ /// — direct write `this->state = arg2`. Retail also fires side-effect
+ /// handlers for the 0x800 (lighting), 0x20 (nodraw), 0x4000 (hidden)
+ /// changed bits; ETHEREAL (0x4) doesn't trigger any of them, so slice 1
+ /// scopes to the bare state-write.
+ ///
+ ///
+ ///
+ /// Implementation: is a value-type record
+ /// copied into per-cell lists, so we rewrite the copy in each cell the
+ /// entity occupies. Unregistered entities are a no-op (callers don't
+ /// have to gate).
+ ///
+ ///
+ public void UpdatePhysicsState(uint entityId, uint newState)
+ {
+ if (!_entityToCells.TryGetValue(entityId, out var cellIds))
+ return; // not registered — no-op
+
+ foreach (var cellId in cellIds)
+ {
+ if (!_cells.TryGetValue(cellId, out var list)) continue;
+ for (int i = 0; i < list.Count; i++)
+ {
+ if (list[i].EntityId == entityId)
+ list[i] = list[i] with { State = newState };
+ }
+ }
+ }
+```
+
+- [ ] **Step 2.4: Run tests to verify they pass (GREEN)**
+
+Run: `dotnet test tests/AcDream.Core.Tests/AcDream.Core.Tests.csproj --filter "FullyQualifiedName~UpdatePhysicsState"`
+Expected: 3 passed.
+
+- [ ] **Step 2.5: Verify full test suite still green (no regressions)**
+
+Run: `dotnet test`
+Expected: All previously-passing tests still pass. **Note:** ~8 pre-existing
+failures may be in the baseline (see `docs/research/2026-05-13-l2d-slice1-shipped-handoff.md`
+"Open concerns"); ensure the count does not increase. Stash + rerun to
+confirm if uncertain: `git stash && dotnet test 2>&1 | findstr Failed` then
+`git stash pop`.
+
+- [ ] **Step 2.6: Commit**
+
+```
+git add src/AcDream.Core/Physics/ShadowObjectRegistry.cs tests/AcDream.Core.Tests/Physics/ShadowObjectRegistryTests.cs
+git commit -m "feat(phys L.2g slice 1): ShadowObjectRegistry.UpdatePhysicsState
+
+New mutator that overwrites cached PhysicsState bits on every shadow copy
+of the named entity. The existing CollisionExemption.ShouldSkip(...) check
+(acclient_2013_pseudo_c.txt:276782) reads the same cached field, so a
+post-spawn ETHEREAL flip is now honored on the next resolver tick without
+any resolver-path change.
+
+Retail anchor: CPhysicsObj::set_state at acclient_2013_pseudo_c.txt:283044.
+Slice 1 scopes to the bare state-write — retail's cosmetic side-effect
+handlers (0x800 lighting, 0x20 nodraw, 0x4000 hidden) don't fire for the
+ETHEREAL bit and stay deferred.
+
+Three TDD tests cover: ETHEREAL flip from 0->0x4; unregistered-entity
+no-op; entity spanning multiple cells gets all copies updated.
+
+Co-Authored-By: Claude Opus 4.7 (1M context) "
+```
+
+---
+
+## Task 3: Wire `0xF74B` into `WorldSession` dispatcher + new event
+
+**Files:**
+- Modify: `src/AcDream.Core.Net/WorldSession.cs` (one new event declaration near the existing `VectorUpdated`/`MotionUpdated` events; one new `else if` branch in the inbound dispatcher near `op == VectorUpdate.Opcode`)
+
+**Reference pattern:** Read the existing `VectorUpdate.Opcode` branch first
+(it's at WorldSession.cs:739–752). Copy its shape exactly.
+
+- [ ] **Step 3.1: Add the public event declaration**
+
+Find the existing `public event Action<...>? VectorUpdated;` declaration
+in `WorldSession.cs` (near line 119, in the events region). Add a sibling:
+
+```csharp
+ ///
+ /// Fires when the server broadcasts a SetState (0xF74B) game
+ /// message — a previously-spawned entity's PhysicsState
+ /// bitmask changed post-CreateObject. Chiefly doors flipping
+ /// ETHEREAL_PS = 0x4 on Use (see ACE
+ /// WorldObjects/Door.cs:127, WorldObject.cs:640-660).
+ /// Subscribers route the new state into
+ /// so the
+ /// existing collision-exemption short-circuit honors the flip on the
+ /// next resolver tick.
+ ///
+ public event Action? StateUpdated;
+```
+
+Place it immediately after the existing `VectorUpdated` event for grep-
+findability.
+
+- [ ] **Step 3.2: Add the dispatcher branch**
+
+In the inbound game-message dispatcher (the chain of `else if (op == X.Opcode)`
+branches in the same file), add this branch immediately after the
+`VectorUpdate.Opcode` branch:
+
+```csharp
+ else if (op == SetState.Opcode)
+ {
+ // L.2g slice 1 (2026-05-12): server broadcasts SetState
+ // (0xF74B) when an entity's PhysicsState changes
+ // post-spawn — chiefly doors flipping ETHEREAL on Use.
+ // Holtburger validated wire format = 16 bytes (opcode +
+ // guid + state + 2×u16 sequence). ACE
+ // GameMessageSetState.cs writes the same field order
+ // but appears to use u32 for the sequences; Task 5's
+ // hex-dump probe settles the actual byte count.
+ var parsed = SetState.TryParse(body);
+ if (parsed is not null)
+ StateUpdated?.Invoke(parsed.Value);
+ }
+```
+
+The `using AcDream.Core.Net.Messages;` directive should already be at the
+top of WorldSession.cs (it's used by every existing parser). Confirm,
+don't add a duplicate.
+
+- [ ] **Step 3.3: Verify build still green**
+
+Run: `dotnet build`
+Expected: Build succeeded, 0 errors.
+
+- [ ] **Step 3.4: Commit**
+
+```
+git add src/AcDream.Core.Net/WorldSession.cs
+git commit -m "feat(phys L.2g slice 1): WorldSession dispatches SetState (0xF74B)
+
+New StateUpdated event + dispatcher branch routes inbound SetState
+messages to subscribers. Mirrors the existing VectorUpdated /
+MotionUpdated event pattern. GameWindow will subscribe in the next
+commit and feed the parsed (guid, newState) pair to
+ShadowObjectRegistry.UpdatePhysicsState.
+
+Co-Authored-By: Claude Opus 4.7 (1M context) "
+```
+
+---
+
+## Task 4: Subscribe in `GameWindow` and feed `ShadowObjectRegistry`
+
+**Files:**
+- Modify: `src/AcDream.App/Rendering/GameWindow.cs` (one new subscription line + one new handler method)
+
+This is the final wiring step. After this commit, the server's "door opened"
+SetState is end-to-end honored by the collision system.
+
+- [ ] **Step 4.1: Add the subscription**
+
+Find the block in `GameWindow.cs` where `_liveSession.MotionUpdated +=
+OnLiveMotionUpdated;` and `_liveSession.PositionUpdated +=
+OnLivePositionUpdated;` are wired (around line 1791). Add:
+
+```csharp
+ _liveSession.StateUpdated += OnLiveStateUpdated;
+```
+
+Place it after `_liveSession.VectorUpdated += OnLiveVectorUpdated;` so the
+event-subscription order is co-located with its peers.
+
+- [ ] **Step 4.2: Add the handler method**
+
+Find the existing `OnLiveVectorUpdated` method body in the same file
+(grep `private void OnLiveVectorUpdated`). Add a sibling handler
+immediately after it:
+
+```csharp
+ ///
+ /// L.2g slice 1: inbound SetState (0xF74B) handler. Propagates the
+ /// new PhysicsState bits into ShadowObjectRegistry so the
+ /// existing check honors
+ /// the flip on the next resolver tick. Chiefly doors:
+ /// server flips ETHEREAL_PS = 0x4 on Use, the door's
+ /// cylinder collision stops blocking the threshold.
+ ///
+ private void OnLiveStateUpdated(AcDream.Core.Net.Messages.SetState.Parsed parsed)
+ {
+ _physicsEngine.ShadowObjects.UpdatePhysicsState(parsed.Guid, parsed.PhysicsState);
+
+ if (AcDream.Core.Physics.PhysicsDiagnostics.ProbeBuildingEnabled)
+ Console.WriteLine(System.FormattableString.Invariant(
+ $"[setstate] guid=0x{parsed.Guid:X8} state=0x{parsed.PhysicsState:X8} instSeq={parsed.InstanceSequence} stateSeq={parsed.StateSequence}"));
+ }
+```
+
+- [ ] **Step 4.3: Verify build still green**
+
+Run: `dotnet build`
+Expected: Build succeeded, 0 errors.
+
+- [ ] **Step 4.4: Smoke-test that no regression breaks the launch path**
+
+Run a quick non-interactive smoke (do NOT do the full visual test yet —
+that's Task 7):
+
+```powershell
+$env:ACDREAM_DAT_DIR = "$env:USERPROFILE\Documents\Asheron's Call"
+$env:ACDREAM_LIVE = "0" # offline; just verify the binary starts
+dotnet run --project src\AcDream.App\AcDream.App.csproj --no-build -c Debug 2>&1 |
+ Select-String -Pattern "Exception|FATAL" |
+ Select-Object -First 5
+```
+
+Then kill the process. Expected: no startup exception, no FATAL. If
+anything blows up, the new handler subscription or the registry mutator
+broke something in the live-session attach path.
+
+- [ ] **Step 4.5: Commit**
+
+```
+git add src/AcDream.App/Rendering/GameWindow.cs
+git commit -m "feat(phys L.2g slice 1): GameWindow routes SetState into registry
+
+End-to-end wiring: WorldSession.StateUpdated fires -> GameWindow
+OnLiveStateUpdated -> ShadowObjectRegistry.UpdatePhysicsState -> next
+resolver tick sees the updated ETHEREAL bit and CollisionExemption
+short-circuits the door cylinder. After this commit the M1 'open the
+inn door' scenario is unblocked at the code-path level; visual
+verification follows in slice 1's manual test (Task 7).
+
+The handler also emits a [setstate] diagnostic line when
+ACDREAM_PROBE_BUILDING is enabled — gives a greppable trail when the
+visual test runs.
+
+Co-Authored-By: Claude Opus 4.7 (1M context) "
+```
+
+---
+
+## Task 5: Hex-dump probe for first SetState payload (wire-byte verification)
+
+**Files:**
+- Modify: `src/AcDream.Core.Net/WorldSession.cs` (extend the existing `else if (op == SetState.Opcode)` branch added in Task 3)
+
+**Why:** ACE's `GameMessageSetState.cs:13-14` writes `Sequences.GetCurrentSequence(...)`
++ `Sequences.GetNextSequence(...)` as `uint` calls — potentially 4 bytes
+each (16-byte total payload) instead of holtburger's 12 bytes. We default to
+holtburger's spec because it's been validated against live retail-format
+servers, but we want one-shot evidence on real wire bytes before declaring
+slice 1 done.
+
+The probe is gated on `ACDREAM_PROBE_BUILDING` (existing env var from
+L.2d slice 1) and fires once per SetState message; the body bytes are
+short enough that this is cheap.
+
+- [ ] **Step 5.1: Extend the dispatcher branch with a hex-dump**
+
+Update the `else if (op == SetState.Opcode)` branch from Task 3 to:
+
+```csharp
+ else if (op == SetState.Opcode)
+ {
+ // L.2g slice 1 (2026-05-12) — see Task 3 above for the
+ // event-routing intent. The probe-gated hex-dump here
+ // captures the wire bytes one-shot per session so we can
+ // confirm holtburger's 12-byte payload format (vs ACE's
+ // GameMessageSetState.cs claim of u32 sequences = 16
+ // bytes) before declaring slice 1 done.
+ if (AcDream.Core.Physics.PhysicsDiagnostics.ProbeBuildingEnabled
+ && !_setStateHexDumped)
+ {
+ _setStateHexDumped = true;
+ var hex = string.Join(" ", body.Take(Math.Min(body.Length, 32))
+ .Select(b => b.ToString("X2")));
+ Console.WriteLine($"[setstate-hex] body.len={body.Length} first-{Math.Min(body.Length, 32)}-bytes: {hex}");
+ }
+
+ var parsed = SetState.TryParse(body);
+ if (parsed is not null)
+ StateUpdated?.Invoke(parsed.Value);
+ }
+```
+
+Add the one-shot flag field near the top of the `WorldSession` class
+(group with other `_dump*Enabled` flags — grep `private bool _` to find
+the cluster):
+
+```csharp
+ /// L.2g slice 1: one-shot guard so the [setstate-hex] probe
+ /// emits the first SetState's body bytes only, not 5–10/sec.
+ private bool _setStateHexDumped;
+```
+
+Note: the `body.Take(...)` requires `using System.Linq;` — already present.
+
+- [ ] **Step 5.2: Verify build still green**
+
+Run: `dotnet build`
+Expected: Build succeeded, 0 errors.
+
+- [ ] **Step 5.3: Commit**
+
+```
+git add src/AcDream.Core.Net/WorldSession.cs
+git commit -m "feat(phys L.2g slice 1): one-shot hex-dump probe for SetState payload
+
+Probe-gated diagnostic (ACDREAM_PROBE_BUILDING) emits the first inbound
+SetState message's body bytes so we can confirm holtburger's 12-byte
+payload format vs ACE's GameMessageSetState.cs claim of u32 sequences
+(16-byte payload). One-shot via _setStateHexDumped — won't flood the
+log when doors auto-close every 30s.
+
+If the hex-dump shows body.len > 16, the parser's body-length gate at
+SetState.cs needs widening (and the seq-field reads shifted accordingly).
+If it shows 16, we ship as-is.
+
+Co-Authored-By: Claude Opus 4.7 (1M context) "
+```
+
+---
+
+## Task 6: Slice 0.5 — extend `[entity-source]` log with `state` + `flags`
+
+**Files:**
+- Modify: `src/AcDream.App/Rendering/GameWindow.cs` (extend the existing `[entity-source]` log line — there are 2 sites; modify both for consistency)
+
+**Why:** The L.2d slice 1 handoff flagged this as a useful "slice 1.6"
+addendum. It's 5 LOC, fold-into-slice-1-freebie. Makes ETHEREAL flips
+greppable end-to-end: spawn -> registry update -> resolver effect.
+
+- [ ] **Step 6.1: Find both `[entity-source]` log sites**
+
+Grep `[entity-source]` in `src/AcDream.App/Rendering/GameWindow.cs` and
+note the two `Console.WriteLine` calls (one is around line 2978 from the
+RegisterLiveEntityForCollision path; the other should be in the
+landblock-baked static registration path — grep confirms by file). Both
+need the same suffix addition.
+
+- [ ] **Step 6.2: Extend both log lines**
+
+For each `[entity-source]` line, append `state=0x{state:X8} flags={flags}`
+to the format string. Example transformation:
+
+Before:
+```csharp
+Console.WriteLine(System.FormattableString.Invariant(
+ $"[entity-source] id=0x{entity.Id:X8} entityId=0x{entity.Id:X8} src=0x{entity.SourceGfxObjOrSetupId:X8} gfxObj=0x{entity.SourceGfxObjOrSetupId:X8} lb=0x{spawn.Position.Value.LandblockId:X8} type=Cylinder note=server-spawn-root"));
+```
+
+After (note: the local variables `state` and `flags` should already be
+in scope at both sites — they're computed just before the
+`ShadowObjects.Register(...)` call; grep upward 5–10 lines from each log
+site to confirm):
+
+```csharp
+Console.WriteLine(System.FormattableString.Invariant(
+ $"[entity-source] id=0x{entity.Id:X8} entityId=0x{entity.Id:X8} src=0x{entity.SourceGfxObjOrSetupId:X8} gfxObj=0x{entity.SourceGfxObjOrSetupId:X8} lb=0x{spawn.Position.Value.LandblockId:X8} type=Cylinder note=server-spawn-root state=0x{state:X8} flags={flags}"));
+```
+
+If the `state` or `flags` variables are scoped differently at one site
+(e.g. one site is for landblock-baked statics that always have state=0),
+substitute the literal `0u` or `EntityCollisionFlags.None` and add a
+comment noting the static-default. Keep the field names identical at both
+sites so a single regex `state=0x([0-9A-F]+)` catches every entry.
+
+- [ ] **Step 6.3: Verify build still green**
+
+Run: `dotnet build`
+Expected: Build succeeded, 0 errors.
+
+- [ ] **Step 6.4: Commit**
+
+```
+git add src/AcDream.App/Rendering/GameWindow.cs
+git commit -m "feat(phys L.2g slice 1): extend [entity-source] log with state + flags
+
+5-LOC freebie folded into L.2g slice 1: the [entity-source] probe now
+emits the PhysicsState bits + EntityCollisionFlags decoded at
+registration. Combined with the new [setstate] handler log line, this
+makes door open/close events fully greppable end-to-end:
+ spawn -> [entity-source] guid=... state=0x00000000 ...
+ Use -> [setstate] guid=... state=0x00000004 ...
+ close -> [setstate] guid=... state=0x00000000 ...
+
+Resolves the 'slice 1.6' suggestion from
+docs/research/2026-05-13-l2d-slice1-shipped-handoff.md.
+
+Co-Authored-By: Claude Opus 4.7 (1M context) "
+```
+
+---
+
+## Task 7: Visual verification at Holtburg inn doorway
+
+**Files:** None — this is a user-driven test. Document the recipe; report
+results in the handoff doc (Task 8).
+
+**Acceptance:**
+1. Walk acdream `+Acdream` into the Holtburg inn doorway. **Expected: blocked at threshold.**
+2. Click the door (Use action). **Expected: door swings open; `[setstate]` log line emits with `state=0x00000004`; walk through clears.**
+3. Wait ~30 seconds. **Expected: door auto-closes; `[setstate]` log line emits with `state=0x00000000`; threshold blocks again.**
+4. Inspect the `[setstate-hex]` line emitted on the first SetState — confirm `body.len=16`. If it's 20 instead, slice 1 has a bug to file as 1b.
+
+- [ ] **Step 7.1: Launch the client with probes enabled**
+
+Wait ~5 seconds since the last close (per CLAUDE.md's logout-before-reconnect
+note) then:
+
+```powershell
+$env:ACDREAM_DAT_DIR = "$env:USERPROFILE\Documents\Asheron's Call"
+$env:ACDREAM_LIVE = "1"
+$env:ACDREAM_TEST_HOST = "127.0.0.1"
+$env:ACDREAM_TEST_PORT = "9000"
+$env:ACDREAM_TEST_USER = "testaccount"
+$env:ACDREAM_TEST_PASS = "testpassword"
+$env:ACDREAM_DEVTOOLS = "1"
+$env:ACDREAM_PROBE_BUILDING = "1"
+$env:ACDREAM_PROBE_RESOLVE = "1"
+dotnet run --project src\AcDream.App\AcDream.App.csproj --no-build -c Debug 2>&1 |
+ Tee-Object -FilePath "launch-l2g-slice1.log"
+```
+
+- [ ] **Step 7.2: Manually perform the four-step scenario**
+
+(User-driven. See Acceptance list above.)
+
+- [ ] **Step 7.3: Inspect the log for the four expected lines**
+
+After closing the client window:
+
+```powershell
+Select-String -Path launch-l2g-slice1.log -Pattern "setstate-hex|setstate.*guid|entity-source.*Door"
+```
+
+Expected matches:
+- One `[setstate-hex] body.len=16 first-16-bytes: 4B F7 ...` line.
+- One `[entity-source] ... name=Door ... state=0x00000000 ...` (or similar).
+- A `[setstate] guid=0x000F.... state=0x00000004 ...` after the Use click.
+- A `[setstate] guid=0x000F.... state=0x00000000 ...` ~30s after the previous.
+
+- [ ] **Step 7.4: Decide ship-or-fix**
+
+Three outcomes:
+- **All four log lines match + door scenario works visually:** slice 1 ships. Proceed to Task 8.
+- **Log lines correct but visual scenario fails (door visually opens but player still blocked):** the resolver is reading stale state from somewhere we haven't found. Stop and file a "slice 1b — find the second cache layer" note.
+- **`[setstate-hex] body.len=20`:** ACE's u32 sequence claim is real. Widen `SetState.cs` body-length gate (`16` -> `20`) and shift sequence reads to `body.Slice(12, 4)` + `body.Slice(16, 4)` (read as `uint`, cast to `ushort` if values are small — high bits will be zero per ACE's `Sequences` design). Re-run from Task 7.1.
+
+---
+
+## Task 8: Ship handoff doc + roadmap update
+
+**Files:**
+- Create: `docs/research/2026-05-XX-l2g-slice1-shipped-handoff.md` (replace `XX` with the actual ship date)
+- Modify: `CLAUDE.md` (replace the "the natural next step is the L.2g slice 1 implementation" paragraph with a "Phase L.2g slice 1 shipped " paragraph mirroring the L.2a paragraph style)
+- Modify: `docs/plans/2026-04-29-movement-collision-conformance.md` (under the L.2g section, add a "Current shipped slice" subsection noting slice 1 + its commit hashes)
+
+- [ ] **Step 8.1: Write the ship handoff doc**
+
+Use the existing handoff at
+`docs/research/2026-05-13-l2d-slice1-shipped-handoff.md` as a template. The
+new doc should cover:
+
+- TL;DR: what landed, did the visual test pass.
+- What shipped (commit hash + subject per commit from Tasks 1–6).
+- What the visual test showed (the four log-line samples from Task 7.3).
+- Wire-byte width resolution (12-byte vs 16-byte — whichever the hex-dump
+ showed).
+- Side findings (anything noticed during visual test — door animation
+ flickers, audio not playing, etc — file under "deferred").
+- Next-session candidates (L.2g slice 2 animation confirmation, deferred UX
+ polish, OR pick from CLAUDE.md's now-revised "Next phase candidates"
+ list).
+
+- [ ] **Step 8.2: Update CLAUDE.md**
+
+Find the "Currently in Phase L.2 (Movement & Collision Conformance)"
+paragraph. Replace its "the natural next step is the L.2g slice 1
+implementation" sentence with "L.2g slice 1 shipped — doors honor
+ETHEREAL flips end-to-end; visual-verified at Holtburg inn doorway." Add
+a "**Phase L.2g slice 1 shipped .**" descriptive paragraph after
+the L.2a paragraph (mirror the L.2a paragraph's depth).
+
+In the "**Next phase candidates**" list, demote the current L.2g item
+out and pick whichever is the next sensible candidate (likely L.2g slice 2
+animation confirmation OR a non-L.2 visual-fidelity item — depends on what
+the visual test in Task 7 showed).
+
+- [ ] **Step 8.3: Update the L.2 plan-of-record**
+
+In `docs/plans/2026-04-29-movement-collision-conformance.md`, under the
+L.2g section, add a "Current shipped slice ():" subsection
+listing the slice 1 commit hashes + their subjects (use git log to fill
+in). Mirror the L.2c "Current shipped slice (2026-04-30):" subsection
+style.
+
+- [ ] **Step 8.4: Commit**
+
+```
+git add CLAUDE.md docs/plans/2026-04-29-movement-collision-conformance.md docs/research/2026-05-XX-l2g-slice1-shipped-handoff.md
+git commit -m "docs(phys L.2g): slice 1 shipped handoff + plan-of-record + CLAUDE.md
+
+Slice 1 visual-verified at Holtburg inn doorway: walking into closed door
+is blocked, Use opens it, walk-through clears, auto-close re-blocks at 30s.
+Wire-byte width settled (see handoff doc).
+
+L.2g slice 2 (animation confirmation) becomes the next candidate IF the
+visual test showed door animation not playing; otherwise slice 2 is a
+verify-only no-op and we move to the next phase candidate.
+
+Co-Authored-By: Claude Opus 4.7 (1M context) "
+```
+
+---
+
+## Plan self-review
+
+**1. Spec coverage check:**
+
+| Spec section | Task |
+|---|---|
+| Slice 1 — parse SetState (0xF74B) | Tasks 1 + 3 + 5 |
+| Slice 1 — plumb new state into ShadowObjectRegistry | Tasks 2 + 4 |
+| Slice 1 — visual verification at Holtburg | Task 7 |
+| Slice 0.5 — extend [entity-source] log with state + flags | Task 6 |
+| Open Q1 — wire-byte width | Task 5 (hex-dump probe) + Task 7.4 (decision branch) |
+| Open Q2 — UpdateMotion drives non-creature entities (door swing animation) | **Deferred to slice 2** (per the spec — animation is verify-only) |
+| Open Q3 — SetState delivered to the player who triggered Use | Task 7 visual test verifies (covered implicitly by the four-step scenario) |
+| Acceptance — design spec, plan-of-record, milestones, CLAUDE.md all reference L.2g | Already done in `2c10dd4`; Task 8 closes the loop with the slice 1 ship handoff |
+| Named retail citation in slice 1 code | Task 2.3 cites `acclient_2013_pseudo_c.txt:283044`; Task 1.3 cites the holtburger struct |
+
+**2. Placeholder scan:** No `TBD`, `TODO`, "fill in later." `` in
+Task 8 is a deliberate placeholder for the engineer to fill in at ship
+time — flagged as such in the handoff doc template, not a plan-writing
+oversight. The `Task 8.1` doc filename uses `2026-05-XX` for the same
+reason.
+
+**3. Type consistency:** `SetState.Parsed(Guid, PhysicsState, InstanceSequence, StateSequence)`
+used consistently in Tasks 1, 3, 4, 5. `UpdatePhysicsState(uint entityId, uint newState)`
+signature consistent in Tasks 2 + 4. `ShadowEntry.State` matches the
+existing struct definition in `ShadowObjectRegistry.cs:262-280`.
+
+**4. Risk surface:** All changes are additive. No resolver edits. No
+broadphase edits. No retail-port semantics changes. If anything goes
+wrong, single-commit revert per task.
+
+---
+
+## Execution
+
+Plan complete. Two execution options when ready:
+
+**1. Subagent-Driven (recommended)** — Dispatch a fresh Sonnet subagent per task (Task 1 alone, Tasks 2 + 3 together, Task 4 + 5 + 6 together, Task 7 user-driven, Task 8 docs). Review between dispatches. Each subagent stays bounded to one commit's worth of changes; parent context stays clean.
+
+**2. Inline Execution** — Drive all tasks in this session using executing-plans. Faster end-to-end but consumes ~4× more parent context.
+
+Total scope estimate: ~6 commits over ~30–60 minutes of work + Task 7 visual test (~10 minutes when ACE + retail client are already running).