diff --git a/Cargo.lock b/Cargo.lock
index 4687ace..35d5317 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6039,6 +6039,7 @@ dependencies = [
  "sprimo-config",
  "sprimo-platform",
  "sprimo-protocol",
+ "sprimo-runtime-core",
  "sprimo-sprite",
  "thiserror 2.0.18",
  "tokio",
diff --git a/crates/sprimo-app/Cargo.toml b/crates/sprimo-app/Cargo.toml
index 251096f..226fc7e 100644
--- a/crates/sprimo-app/Cargo.toml
+++ b/crates/sprimo-app/Cargo.toml
@@ -15,6 +15,7 @@ sprimo-api = { path = "../sprimo-api" }
 sprimo-config = { path = "../sprimo-config" }
 sprimo-platform = { path = "../sprimo-platform" }
 sprimo-protocol = { path = "../sprimo-protocol" }
+sprimo-runtime-core = { path = "../sprimo-runtime-core" }
 sprimo-sprite = { path = "../sprimo-sprite" }
 thiserror.workspace = true
 tokio.workspace = true
diff --git a/crates/sprimo-app/src/main.rs b/crates/sprimo-app/src/main.rs
index d5eb0f5..7ad9db9 100644
--- a/crates/sprimo-app/src/main.rs
+++ b/crates/sprimo-app/src/main.rs
@@ -6,10 +6,9 @@ use bevy::render::render_resource::{Extent3d, TextureDimension, TextureFormat};
 use bevy::window::{PrimaryWindow, WindowLevel, WindowMode, WindowPlugin, WindowPosition};
 use image::{DynamicImage, GenericImageView, Rgba};
 use raw_window_handle::{HasWindowHandle, RawWindowHandle};
-use sprimo_api::{ApiConfig, ApiState};
-use sprimo_config::{save, AppConfig, ConfigError};
 use sprimo_platform::{create_adapter, PlatformAdapter};
 use sprimo_protocol::v1::{CommandEnvelope, FrontendCommand, FrontendState, FrontendStateSnapshot};
+use sprimo_runtime_core::{RuntimeCore, RuntimeCoreError};
 use sprimo_sprite::{
     load_manifest, resolve_pack_path, AnimationDefinition, SpriteError, SpritePackManifest,
 };
@@ -20,8 +19,7 @@ use std::sync::{Arc, RwLock};
 use std::time::Duration;
 use thiserror::Error;
 use tokio::runtime::Runtime;
-use tokio::sync::mpsc as tokio_mpsc;
-use tracing::{error, info, warn};
+use tracing::{info, warn};
 
 const APP_NAME: &str = "sprimo";
 const DEFAULT_PACK: &str = "default";
@@ -35,7 +33,7 @@ const WINDOWS_COLOR_KEY: [u8; 3] = [255, 0, 255];
 #[derive(Debug, Error)]
 enum AppError {
     #[error("{0}")]
-    Config(#[from] ConfigError),
+    RuntimeCore(#[from] RuntimeCoreError),
 }
 
 #[derive(Resource, Clone)]
@@ -45,10 +43,7 @@ struct SharedSnapshot(Arc<RwLock<FrontendStateSnapshot>>);
 struct PlatformResource(Arc<dyn PlatformAdapter>);
 
 #[derive(Resource)]
-struct ConfigResource {
-    path: PathBuf,
-    config: AppConfig,
-}
+struct RuntimeCoreResource(Arc<RuntimeCore>);
 
 #[derive(Resource, Copy, Clone)]
 struct DurableState {
@@ -181,35 +176,30 @@ fn main() -> Result<(), AppError> {
         .compact()
         .init();
 
-    let (config_path, mut config) = sprimo_config::load_or_create(APP_NAME)?;
-    if config.window.click_through {
-        config.window.click_through = false;
-        if let Err(err) = save(&config_path, &config) {
-            warn!(%err, "failed to persist click-through disable at startup");
-        }
-    }
     let platform: Arc<dyn PlatformAdapter> = create_adapter().into();
-    let capabilities = platform.capabilities();
-
-    let mut snapshot = FrontendStateSnapshot::idle(capabilities);
-    snapshot.x = config.window.x;
-    snapshot.y = config.window.y;
-    snapshot.scale = config.window.scale;
-    snapshot.flags.click_through = false;
-    snapshot.flags.always_on_top = config.window.always_on_top;
-    snapshot.flags.visible = config.window.visible;
-    snapshot.active_sprite_pack = config.sprite.selected_pack.clone();
-    let shared_snapshot = Arc::new(RwLock::new(snapshot));
+    let runtime_core = Arc::new(RuntimeCore::new(APP_NAME, platform.capabilities())?);
+    let shared_snapshot = runtime_core.snapshot();
+    let config = runtime_core
+        .config()
+        .read()
+        .expect("runtime core config lock poisoned")
+        .clone();
 
     let runtime = Runtime::new().expect("tokio runtime");
-    let (api_command_tx, api_command_rx) = tokio_mpsc::channel(1_024);
     let (bevy_command_tx, bevy_command_rx) = mpsc::channel();
     let (hotkey_tx, hotkey_rx) = mpsc::channel();
 
-    spawn_api(&runtime, &config, Arc::clone(&shared_snapshot), api_command_tx);
+    runtime_core.spawn_api(&runtime);
+    let command_rx = runtime_core.command_receiver();
     runtime.spawn(async move {
-        let mut rx = api_command_rx;
-        while let Some(command) = rx.recv().await {
+        loop {
+            let next = {
+                let mut receiver = command_rx.lock().await;
+                receiver.recv().await
+            };
+            let Some(command) = next else {
+                break;
+            };
             if bevy_command_tx.send(command).is_err() {
                 break;
             }
@@ -245,11 +235,8 @@ fn main() -> Result<(), AppError> {
     app.insert_resource(ClearColor(window_clear_color()));
 
     app.insert_resource(SharedSnapshot(shared_snapshot));
+    app.insert_resource(RuntimeCoreResource(Arc::clone(&runtime_core)));
     app.insert_resource(PlatformResource(Arc::clone(&platform)));
-    app.insert_resource(ConfigResource {
-        path: config_path,
-        config,
-    });
     app.insert_resource(DurableState {
         state: FrontendState::Idle,
     });
@@ -281,23 +268,6 @@ fn main() -> Result<(), AppError> {
     Ok(())
 }
 
-fn spawn_api(
-    runtime: &Runtime,
-    config: &AppConfig,
-    shared_snapshot: Arc<RwLock<FrontendStateSnapshot>>,
-    api_command_tx: tokio_mpsc::Sender<CommandEnvelope>,
-) {
-    let mut api_config = ApiConfig::default_with_token(config.api.auth_token.clone());
-    api_config.bind_addr = ([127, 0, 0, 1], config.api.port).into();
-    let api_state = Arc::new(ApiState::new(api_config.clone(), shared_snapshot, api_command_tx));
-
-    runtime.spawn(async move {
-        if let Err(err) = sprimo_api::run_server(api_config, api_state).await {
-            error!(%err, "api server exited");
-        }
-    });
-}
-
 fn default_asset_root() -> PathBuf {
     std::env::current_dir()
         .unwrap_or_else(|_| PathBuf::from("."))
@@ -307,7 +277,7 @@ fn default_asset_root() -> PathBuf {
 
 fn setup_scene(
     mut commands: Commands,
-    config: Res<ConfigResource>,
+    runtime_core: Res<RuntimeCoreResource>,
     root: Res<SpritePackRoot>,
     mut texture_layouts: ResMut<Assets<TextureAtlasLayout>>,
     mut images: ResMut<Assets<Image>>,
@@ -323,7 +293,14 @@ fn setup_scene(
         ..default()
     });
 
-    let selected = config.config.sprite.selected_pack.clone();
+    let selected = runtime_core
+        .0
+        .config()
+        .read()
+        .expect("runtime core config lock poisoned")
+        .sprite
+        .selected_pack
+        .clone();
     let runtime = match load_pack_runtime(
         &root.asset_root,
         &selected,
@@ -749,8 +726,7 @@ fn attach_window_handle_once(
 fn poll_hotkey_recovery(
     ingress: NonSendMut<HotkeyIngress>,
     platform: Res<PlatformResource>,
-    mut config: ResMut<ConfigResource>,
-    snapshot: Res<SharedSnapshot>,
+    runtime_core: Res<RuntimeCoreResource>,
     mut pet_query: Query<&mut Visibility, With<PetSprite>>,
 ) {
     while ingress.0.try_recv().is_ok() {
@@ -761,18 +737,12 @@ fn poll_hotkey_recovery(
         if let Ok(mut visibility) = pet_query.get_single_mut() {
             *visibility = Visibility::Visible;
         }
-
-        config.config.window.always_on_top = true;
-        config.config.window.visible = true;
-        if let Err(err) = save(&config.path, &config.config) {
-            warn!(%err, "failed to persist config after hotkey recovery");
-        }
-
-        if let Ok(mut guard) = snapshot.0.write() {
-            guard.flags.click_through = false;
-            guard.flags.always_on_top = true;
-            guard.flags.visible = true;
-            guard.last_error = None;
+        if let Err(err) = runtime_core.0.apply_command(&FrontendCommand::SetFlags {
+            click_through: None,
+            always_on_top: Some(true),
+            visible: Some(true),
+        }) {
+            warn!(%err, "failed to persist recovery flag config");
         }
     }
 }
@@ -784,7 +754,7 @@ fn poll_backend_commands(
     asset_server: Res<AssetServer>,
     mut images: ResMut<Assets<Image>>,
     mut texture_layouts: ResMut<Assets<TextureAtlasLayout>>,
-    mut config: ResMut<ConfigResource>,
+    runtime_core: Res<RuntimeCoreResource>,
     snapshot: Res<SharedSnapshot>,
     mut durable_state: ResMut<DurableState>,
     mut reset: ResMut<PendingStateReset>,
@@ -800,6 +770,7 @@ fn poll_backend_commands(
         let Ok(envelope) = ingress.0.try_recv() else {
             break;
         };
+        let command = envelope.command;
 
         let Ok((mut transform, mut visibility, mut atlas, mut image_handle)) =
             pet_query.get_single_mut()
@@ -807,7 +778,14 @@ fn poll_backend_commands(
             continue;
         };
 
-        match envelope.command {
+        if !matches!(command, FrontendCommand::SetSpritePack { .. }) {
+            if let Err(err) = runtime_core.0.apply_command(&command) {
+                warn!(%err, "failed to apply command in runtime core");
+                continue;
+            }
+        }
+
+        match command {
             FrontendCommand::SetState { state, ttl_ms } => {
                 if !matches!(state, FrontendState::Success | FrontendState::Error) {
                     durable_state.state = state;
@@ -878,8 +856,11 @@ fn poll_backend_commands(
                             window.resolution.set(size.x, size.y);
                         }
 
-                        config.config.sprite.selected_pack = requested;
-                        if let Err(err) = save(&config.path, &config.config) {
+                        if let Err(err) = runtime_core.0.apply_command(
+                            &FrontendCommand::SetSpritePack {
+                                pack_id_or_path: requested.clone(),
+                            },
+                        ) {
                             warn!(%err, "failed to persist sprite pack selection");
                         }
 
@@ -899,37 +880,17 @@ fn poll_backend_commands(
                 }
             }
             FrontendCommand::SetTransform { x, y, scale, .. } => {
-                if let Some(value) = x {
-                    config.config.window.x = value;
-                }
-                if let Some(value) = y {
-                    config.config.window.y = value;
-                }
                 if let Some(value) = scale {
                     transform.scale = Vec3::splat(value);
-                    config.config.window.scale = value;
                     if let Ok(mut window) = window_query.get_single_mut() {
                         let size = window_size_for_pack(&current_pack.runtime, value);
                         window.resolution.set(size.x, size.y);
                     }
                 }
-                let _ = platform
-                    .0
-                    .set_window_position(config.config.window.x, config.config.window.y);
-                if let Err(err) = save(&config.path, &config.config) {
-                    warn!(%err, "failed to persist transform config");
-                }
-                if let Ok(mut guard) = snapshot.0.write() {
-                    if let Some(value) = x {
-                        guard.x = value;
+                if x.is_some() || y.is_some() {
+                    if let Ok(guard) = snapshot.0.read() {
+                        let _ = platform.0.set_window_position(guard.x, guard.y);
                     }
-                    if let Some(value) = y {
-                        guard.y = value;
-                    }
-                    if let Some(value) = scale {
-                        guard.scale = value;
-                    }
-                    guard.last_error = None;
                 }
             }
             FrontendCommand::SetFlags {
@@ -937,36 +898,18 @@ fn poll_backend_commands(
                 always_on_top,
                 visible,
             } => {
-                if click_through.is_some() {
-                    config.config.window.click_through = false;
-                }
+                let _ = click_through;
                 if let Some(value) = always_on_top {
                     let _ = platform.0.set_always_on_top(value);
-                    config.config.window.always_on_top = value;
                 }
                 if let Some(value) = visible {
                     let _ = platform.0.set_visible(value);
-                    config.config.window.visible = value;
                     *visibility = if value {
                         Visibility::Visible
                     } else {
                         Visibility::Hidden
                     };
                 }
-
-                if let Err(err) = save(&config.path, &config.config) {
-                    warn!(%err, "failed to persist flag config");
-                }
-                if let Ok(mut guard) = snapshot.0.write() {
-                    guard.flags.click_through = false;
-                    if let Some(value) = always_on_top {
-                        guard.flags.always_on_top = value;
-                    }
-                    if let Some(value) = visible {
-                        guard.flags.visible = value;
-                    }
-                    guard.last_error = None;
-                }
             }
             FrontendCommand::Toast { text, .. } => {
                 info!(toast = text, "toast command received");
@@ -977,6 +920,7 @@ fn poll_backend_commands(
 
 fn tick_state_reset(
     time: Res<Time>,
+    runtime_core: Res<RuntimeCoreResource>,
     mut reset: ResMut<PendingStateReset>,
     mut animation: ResMut<AnimationResource>,
     current_pack: Res<CurrentPackResource>,
@@ -993,6 +937,10 @@ fn tick_state_reset(
 
     let next_state = reset.revert_to;
     let next_animation = default_animation_for_state(next_state);
+    let _ = runtime_core.0.apply_command(&FrontendCommand::SetState {
+        state: next_state,
+        ttl_ms: None,
+    });
     set_animation(&mut animation, &current_pack.runtime.clips, next_animation);
     if let Ok(mut atlas) = atlas_query.get_single_mut() {
         if let Some(frame) = current_frame(&animation, &current_pack.runtime.clips) {
diff --git a/docs/BEVY_WINDOW_VERIFICATION.md b/docs/BEVY_WINDOW_VERIFICATION.md
new file mode 100644
index 0000000..9bb3dce
--- /dev/null
+++ b/docs/BEVY_WINDOW_VERIFICATION.md
@@ -0,0 +1,194 @@
+# Bevy Window Management Verification (Windows-First)
+
+Date: 2026-02-13
+
+## Purpose
+
+This document defines a logical verification workflow for `sprimo-app` window management.
+It combines code-path assertions with lightweight runtime validation.
+
+Primary focus:
+
+- window visibility behavior
+- always-on-top behavior
+- position and scale handling
+- recovery hotkey behavior
+- snapshot/config consistency
+
+## Scope
+
+In scope:
+
+- `crates/sprimo-app/src/main.rs`
+- `crates/sprimo-platform/src/lib.rs`
+- window-related runtime-core integration path in `sprimo-app`
+- API commands: `SetTransform`, `SetFlags`
+
+Out of scope:
+
+- tray/menu behavior
+- tauri frontend window behavior
+- long soak/performance testing
+
+## Requirements Traceability
+
+| Requirement | Intent | Code path(s) |
+|---|---|---|
+| FR-FW-1 | Borderless/transparent overlay | `crates/sprimo-app/src/main.rs` window setup (`decorations=false`, clear color/transparent mode) |
+| FR-FW-2 | Always-on-top toggle | `crates/sprimo-app/src/main.rs` (`SetFlags.always_on_top`), `crates/sprimo-platform/src/lib.rs` (`set_always_on_top`) |
+| FR-FW-3 | Recovery to visible/interactive | `crates/sprimo-app/src/main.rs` (`poll_hotkey_recovery`) |
+| FR-FW-4 | Positioning persistence + move | `crates/sprimo-app/src/main.rs` (`SetTransform x/y`, startup position), runtime-core config persistence |
+| FR-FW-5 | Position handling under monitor/DPI context | logical verification of position updates via platform adapter + snapshot/config |
+
+## Code-Path Logical Checklist
+
+1. Startup invariants:
+- window is undecorated and non-resizable
+- startup position uses persisted `window.x` / `window.y`
+- startup top-most intent is configured
+
+2. Handle-attach invariants:
+- `attach_window_handle_once` applies at most once
+- on Windows, native handle attach occurs before platform calls
+- initial snapshot values are applied to platform (`always_on_top`, `visible`, `position`)
+
+3. Command invariants:
+- `SetTransform.scale` updates sprite scale and window size (`window_size_for_pack`)
+- `SetTransform.x/y` updates logical position state and issues platform move
+- `SetFlags.always_on_top` triggers platform top-most call
+- `SetFlags.visible` triggers platform visibility call and Bevy `Visibility`
+
+4. Recovery invariants:
+- hotkey path enforces `visible=true` and `always_on_top=true`
+- recovery updates logical state via runtime-core command path
+
+5. Persistence/snapshot invariants:
+- window fields (`x`, `y`, `scale`, `flags`) roundtrip through runtime-core
+- `/v1/state` stays consistent with command outcomes
+
+6. Degradation invariants (non-Windows):
+- no-op adapter does not crash on window commands
+- capability semantics remain conservative
+
+## Lightweight Runtime Checklist (Windows)
+
+Preconditions:
+
+- run `sprimo-app`
+- resolve token/port from `%APPDATA%/sprimo/config/config.toml`
+
+### Scenario 1: Baseline
+
+1. `GET /v1/health`
+2. `GET /v1/state` with bearer token
+3. Record `x`, `y`, `scale`, `flags.visible`, `flags.always_on_top`
+
+Expected:
+
+- health endpoint alive
+- state endpoint authorized
+- window fields present and coherent
+
+### Scenario 2: Position Command
+
+1. Send `SetTransform` with `x` and `y`.
+2. Re-check `/v1/state`.
+
+Expected:
+
+- `x`/`y` update in snapshot
+- window visibly moves
+
+### Scenario 3: Scale Command
+
+1. Send `SetTransform` with `scale`.
+2. Re-check `/v1/state`.
+
+Expected:
+
+- `scale` updates
+- window dimensions update according to frame size + padding
+
+### Scenario 4: Visibility Toggle
+
+1. Send `SetFlags { visible: false }`.
+2. Send `SetFlags { visible: true }`.
+3. Re-check `/v1/state`.
+
+Expected:
+
+- visible flag transitions correctly
+- window hides/shows without crash
+
+### Scenario 5: Always-On-Top Toggle
+
+1. Send `SetFlags { always_on_top: false }`.
+2. Send `SetFlags { always_on_top: true }`.
+3. Re-check `/v1/state`.
+
+Expected:
+
+- top-most flag transitions correctly
+- OS behavior matches expected z-order changes
+
+### Scenario 6: Recovery Hotkey
+
+1. Move to non-ideal state (hidden and/or not top-most).
+2. Trigger configured recovery hotkey (default `Ctrl+Alt+P`).
+3. Re-check `/v1/state`.
+
+Expected:
+
+- forces `visible=true`
+- forces `always_on_top=true`
+
+### Scenario 7: Restart Persistence
+
+1. Restart `sprimo-app`.
+2. Re-check `/v1/state`.
+
+Expected:
+
+- `x`, `y`, `scale`, `always_on_top`, `visible` persist
+
+## Suggested Command Set
+
+```powershell
+cargo check -p sprimo-app
+cargo check -p sprimo-platform
+cargo check -p sprimo-runtime-core
+cargo test -p sprimo-app
+cargo test -p sprimo-runtime-core
+just qa-validate
+```
+
+Optional runtime stress after directed checks:
+
+```powershell
+just random-backend-test
+```
+
+## Pass / Fail Criteria
+
+Pass:
+
+- all logical assertions hold
+- runtime scenarios behave as expected
+- `/v1/state` remains consistent with visible behavior
+- no crashes/panics in window-command paths
+
+Fail:
+
+- mismatch between command outcome and snapshot
+- recovery hotkey fails to restore visible top-most state
+- restart persistence for window fields fails
+- any crash in window-management flow
+
+## Evidence Expectations
+
+For issue-driven verification, attach:
+
+- command summary
+- before/after screenshots
+- `/v1/state` snapshots before and after key transitions
+- lifecycle updates in `issues/issueN.md` per `docs/QA_WORKFLOW.md`
diff --git a/docs/IMPLEMENTATION_STATUS.md b/docs/IMPLEMENTATION_STATUS.md
index 94aebc2..df7801c 100644
--- a/docs/IMPLEMENTATION_STATUS.md
+++ b/docs/IMPLEMENTATION_STATUS.md
@@ -18,7 +18,7 @@ Date: 2026-02-12
 | Build/package automation | Implemented (Windows) | `justfile` and `scripts/package_windows.py` generate portable ZIP + SHA256 |
 | Random backend API tester | Implemented | `scripts/random_backend_tester.py` with `just random-backend-test` and strict variant |
 | QA/documentation workflow | Implemented | `docs/QA_WORKFLOW.md`, issue/evidence templates, and `scripts/qa_validate.py` with `just qa-validate` |
-| Shared runtime core | In progress | `sprimo-runtime-core` extracted with shared config/snapshot/API startup and command application |
+| Shared runtime core | Implemented | `sprimo-runtime-core` now backs both Tauri and Bevy startup, snapshot/config ownership, and API wiring |
 | Tauri alternative frontend | In progress | `sprimo-tauri` now runs runtime-core/API + PixiJS sprite rendering shell; scale updates now auto-fit window to avoid top clipping |
 | Tauri runtime testing workflow | Implemented | `docs/TAURI_RUNTIME_TESTING.md` defines strict workspace testing; packaged mode pending packaging support |
 
@@ -28,5 +28,4 @@ Date: 2026-02-12
 2. Linux/macOS overlay behavior remains best-effort with no-op platform adapter.
 3. `/v1/state` diagnostics are minimal; error history is not persisted beyond latest runtime error.
 4. Issue 1 runtime after-fix screenshot evidence is still pending before closure.
-5. `sprimo-app` is not yet refactored to consume `sprimo-runtime-core` directly.
-6. `sprimo-tauri` still lacks tray/menu/window-behavior parity and full acceptance parity tests.
+5. `sprimo-tauri` still lacks tray/menu/window-behavior parity and full acceptance parity tests.
diff --git a/docs/QA_WORKFLOW.md b/docs/QA_WORKFLOW.md
index bceb77d..f3fd01a 100644
--- a/docs/QA_WORKFLOW.md
+++ b/docs/QA_WORKFLOW.md
@@ -79,6 +79,9 @@ just random-backend-test
 ```
 
 For runtime behavior issues, include screenshot capture paths in the issue file.
+For Bevy window-management verification workflows, use:
+
+- `docs/BEVY_WINDOW_VERIFICATION.md`
 
 ## Definition of Done
 
diff --git a/docs/RELEASE_TESTING.md b/docs/RELEASE_TESTING.md
index b882659..00b9d34 100644
--- a/docs/RELEASE_TESTING.md
+++ b/docs/RELEASE_TESTING.md
@@ -98,6 +98,7 @@ Legacy issues may reference `issues/screenshots/issueN.png` as before evidence.
 ## Tauri Runtime Behavior Testing
 
 Authoritative workflow: `docs/TAURI_RUNTIME_TESTING.md`.
+Bevy window-management verification workflow: `docs/BEVY_WINDOW_VERIFICATION.md`.
 
 ### Workspace Mode (Required Now)
 
diff --git a/docs/TAURI_FRONTEND_DESIGN.md b/docs/TAURI_FRONTEND_DESIGN.md
index 5660f56..c45369a 100644
--- a/docs/TAURI_FRONTEND_DESIGN.md
+++ b/docs/TAURI_FRONTEND_DESIGN.md
@@ -58,7 +58,5 @@ Frontend:
 
 ## Remaining Work
 
-1. Move Bevy runtime flow to consume `sprimo-runtime-core` as primary state authority.
-2. Add tray/menu parity and window behavior parity with Bevy path.
-3. Extend packaging scripts to include `sprimo-tauri` artifact path.
-4. Add frontend parity acceptance tests (Bevy vs Tauri state transitions).
+1. Add tray/menu parity and window behavior parity with Bevy path.
+2. Add frontend parity acceptance tests (Bevy vs Tauri state transitions).