diff --git a/docs/plans/2026-07-25-modern-runtime-slice-j.md b/docs/plans/2026-07-25-modern-runtime-slice-j.md
index 4d713f29..a1b0aa97 100644
--- a/docs/plans/2026-07-25-modern-runtime-slice-j.md
+++ b/docs/plans/2026-07-25-modern-runtime-slice-j.md
@@ -143,6 +143,9 @@ git revert 854d9e9cd13092bd5aaa3cf025d73eeb4600e9f8
 
 ### J2 — session lifetime and ordered transport group
 
+**Detailed execution plan:**
+[`2026-07-25-modern-runtime-slice-j2.md`](2026-07-25-modern-runtime-slice-j2.md).
+
 - Remove App presentation dependencies from `LiveSessionController`,
   `LiveSessionHost`, lifecycle host, event router, and command router.
 - Move the same owner instances into Runtime with Core.Net transport and
diff --git a/docs/plans/2026-07-25-modern-runtime-slice-j2.md b/docs/plans/2026-07-25-modern-runtime-slice-j2.md
new file mode 100644
index 00000000..ef4bb7bd
--- /dev/null
+++ b/docs/plans/2026-07-25-modern-runtime-slice-j2.md
@@ -0,0 +1,190 @@
+# Modern runtime Slice J2 — session lifetime and ordered transport
+
+**Status:** ACTIVE
+**Parent:** `2026-07-25-modern-runtime-slice-j.md`, J2
+**Production base:** `854d9e9cd13092bd5aaa3cf025d73eeb4600e9f8`
+**J1 documentation:** `f84624b1e9b83f928debdbe65a5a1576b999ee34`
+
+## 1. Objective
+
+Move the one canonical live-session lifetime, transport generation, ordered
+inbound subscription owner, and route activation/teardown transaction from
+`AcDream.App` into `AcDream.Runtime`.
+
+The move is structural. It must preserve the exact current connect, character
+selection, EnterWorld, packet dispatch, command activation, tick, reconnect,
+logout, and retryable cleanup order. App remains the graphical host and
+supplies credentials, retained-UI/domain callbacks, the graphical command
+projection, and presentation reset acknowledgements.
+
+## 2. Fixed ownership after J2
+
+`AcDream.Runtime` owns:
+
+- the exact `WorldSession` generation and its connect/enter/tick/dispose
+  transaction;
+- generation validation and live-session lifecycle state;
+- the serial route lifecycle: attach inbound before Connect, activate outbound
+  only after EnterWorld, make commands inert before detaching inbound;
+- the retryable teardown suffix and exact acknowledgement stages;
+- the complete ordered inbound subscription set and all Core/Core.Net event
+  wiring;
+- connection options with no dependency on App `RuntimeOptions`;
+- the production endpoint/session operations and deterministic operations
+  seam used by no-window tests.
+
+`AcDream.App` owns:
+
+- conversion from `RuntimeOptions` into immutable Runtime connection options;
+- graphical reset, identity, layout, toolbar, settings, dialog, and
+  presentation callbacks;
+- the `ICommandBus` projection needed by the current UI until gameplay command
+  groups move in J4/J5;
+- graphical source adapters for existing App interfaces while those consumer
+  groups await their own J3–J6 migrations.
+
+The App adapters borrow the Runtime session and command route. They do not
+dispose the transport, track another generation, retain a second active route,
+or mirror in-world state.
+
+## 3. Type and file migration
+
+### J2.1 — Runtime lifetime contracts
+
+Add under `src/AcDream.Runtime/Session/`:
+
+- `LiveSessionConnectOptions`
+- `RuntimeLiveSessionController`
+- `RuntimeLiveSessionHost`
+- `RuntimeLiveSessionBinding`
+- `IRuntimeLiveSessionLifecycleHost`
+- `IRuntimeLiveSessionOperations`
+- `IRuntimeLiveSessionEventRoute`
+- `IRuntimeLiveSessionCommandRoute`
+- the Runtime-only lifecycle host and retryable route rollback owner
+
+The host implements the J1 `IRuntimeSessionCommands` surface directly. Start,
+Reconnect, and Stop are generation-gated at that owner; the J1 App command
+adapter no longer translates a second session result or invents teardown
+stages.
+
+`RuntimeLiveSessionController` exposes only borrowed state:
+`CurrentSession`, `IsInWorld`, `Generation`, and `Tick`. It carries no UI
+command bus and implements no App interface.
+
+### J2.2 — Ordered inbound route move
+
+Move the existing `LiveSessionEventRouter` and
+`LiveSessionSubscriptionSet` into Runtime without changing subscription order:
+
+1. object/property table wiring;
+2. combat-state wiring;
+3. entity and environment messages;
+4. inventory/item state;
+5. character/spell state;
+6. social/chat state.
+
+The existing accepting gate, reverse-order retryable unsubscribe, construction
+rollback, and reentrant-cleanup rejection remain line-for-line. The route
+bindings remain delegates over current owners for J2; their owner groups move
+in J3/J4.
+
+### J2.3 — Graphical host adapter
+
+Replace the App lifetime implementation with focused adapters:
+
+- a session source bridge for existing App `IsInWorld`, `CurrentSession`,
+  frame-tick, and retained-UI seams;
+- a graphical route factory that constructs the moved Runtime event router and
+  the current App command projection;
+- a single active-command projection whose retained UI reference becomes
+  inert before route detachment;
+- graphical lifecycle callbacks for reset, selection, EnterWorld, connecting,
+  and connected presentation.
+
+Delete the superseded App controller, lifecycle-host logic, subscription
+owner, and route rollback implementation in the same commit. Do not keep
+delegating compatibility copies of lifetime state.
+
+### J2.4 — Test ownership
+
+Move controller, host, lifecycle, event-router, and subscription tests into
+`AcDream.Runtime.Tests`. Preserve every existing call-order, duplicate start,
+reentrant reconnect/stop/dispose, rollback-failure, stale generation, malformed
+packet, and retryable teardown case.
+
+Keep graphical command-projection and App bridge tests in
+`AcDream.App.Tests`. Add assertions that:
+
+- the bridge has no generation or in-world backing fields;
+- the command projection has at most one borrowed active route;
+- stale command references are inert after replacement;
+- press-time graphical input still reaches the same owner synchronously.
+
+Add a Runtime-only construction test that creates the production lifetime
+graph with deterministic transport operations, enters and exits a session,
+and verifies that App, UI, Silk.NET, OpenAL, Arch, and ImGui assemblies are
+not loaded.
+
+## 4. Exact behavioral order
+
+Start:
+
+1. advance generation;
+2. drain any retired teardown suffix;
+3. reset the supplied host when required;
+4. validate enabled state and credentials;
+5. resolve endpoint and create the one `WorldSession`;
+6. construct and attach all inbound routes;
+7. publish connecting state;
+8. Connect and receive the character list;
+9. publish connected state;
+10. select the first available character and publish identity;
+11. EnterWorld;
+12. activate the outbound command route;
+13. mark in-world and publish entered-world presentation.
+
+Stop/replacement:
+
+1. advance generation and reject further old-generation commands;
+2. make the active graphical command route inert;
+3. detach inbound subscriptions in reverse order;
+4. dispose `WorldSession`, preserving its graceful F653/disconnect behavior;
+5. detach the exact host/session pair;
+6. reset domain and presentation state;
+7. acknowledge only the completed stages.
+
+If a stage throws, the exact remaining suffix is retained. A retry never
+replays a completed stage.
+
+## 5. Acceptance
+
+Focused:
+
+- Runtime lifetime and event-route suites all pass after moving from App;
+- App graphical bridge and command projection suites pass;
+- J1 normalized traces are identical before and after the move;
+- source/dependency guards find no Runtime presentation/backend dependency;
+- Runtime-only session construction and teardown load no forbidden assembly.
+
+Complete:
+
+- `dotnet build AcDream.slnx -c Release`;
+- full Release solution tests;
+- connected capped login/six-checkpoint/logout plus fresh uncapped reconnect
+  on the exact binary;
+- both processes exit gracefully;
+- no packet/order, reveal, route, teardown, or resource-convergence failure.
+
+J2 changes no pixels, input feel, or retail algorithm. A separate user visual
+pause is therefore not required unless the connected gate exposes a
+presentation symptom.
+
+## 6. Rollback
+
+The exact J2 rollback commit is recorded here before its connected gate. J1
+remains independently reversible:
+
+```text
+git revert 854d9e9cd13092bd5aaa3cf025d73eeb4600e9f8
+```
diff --git a/docs/research/2026-07-25-slice-j1-runtime-contract-closeout.md b/docs/research/2026-07-25-slice-j1-runtime-contract-closeout.md
index 936a18d1..88677265 100644
--- a/docs/research/2026-07-25-slice-j1-runtime-contract-closeout.md
+++ b/docs/research/2026-07-25-slice-j1-runtime-contract-closeout.md
@@ -67,4 +67,3 @@ J0 remains independently reversible with:
 ```text
 git revert b632672e5ccabfb44c551e08f1c411ab2669c44a
 ```
-