diff --git a/solitaire_core/src/game_state.rs b/solitaire_core/src/game_state.rs
index 107f649..0e44968 100644
--- a/solitaire_core/src/game_state.rs
+++ b/solitaire_core/src/game_state.rs
@@ -8,8 +8,8 @@ use crate::klondike_adapter::{
 };
 use card_game::{Card, Game as _, Session, SessionConfig};
 use klondike::{
-    DstFoundation, DstTableau, Foundation, Klondike, KlondikeConfig, KlondikeInstruction,
-    KlondikePile, KlondikePileStack, SkipCards, Tableau, TableauStack,
+    DrawStockConfig, DstFoundation, DstTableau, Foundation, Klondike, KlondikeConfig,
+    KlondikeInstruction, KlondikePile, KlondikePileStack, SkipCards, Tableau, TableauStack,
 };
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
@@ -150,27 +150,28 @@ pub struct TestPileState {
     pub tableau: std::collections::HashMap<Tableau, Vec<(Card, bool)>>,
     /// Per-foundation overrides.  Missing keys fall back to the session.
     pub foundation: std::collections::HashMap<Foundation, Vec<Card>>,
+    /// Override for the derived `move_count()`.  `None` means "use session
+    /// history length".
+    pub move_count: Option<u32>,
+    /// Override for the derived `is_won()`.  `None` means "use session win
+    /// state".
+    pub won: Option<bool>,
+    /// Override for the derived `is_auto_completable()`.  `None` means "derive
+    /// from session state".
+    pub auto_completable: Option<bool>,
 }
 
 /// Full state of an in-progress Klondike Solitaire game.
 #[derive(Debug, Clone)]
 pub struct GameState {
-    /// Whether the player draws one or three cards from the stock per turn.
-    pub draw_mode: DrawMode,
     /// Top-level mode (Classic / Zen).
     pub mode: GameMode,
     /// Current game score. Can be negative (undo penalties subtract from score).
     pub score: i32,
-    /// Total moves made this game, including draws and stock recycles.
-    pub move_count: u32,
     /// Seconds elapsed since the game started, used for time-bonus scoring.
     pub elapsed_seconds: u64,
     /// RNG seed used to deal this game. Same seed always produces the same layout.
     pub seed: u64,
-    /// True once all 52 cards are on the foundations. No further moves are accepted.
-    pub is_won: bool,
-    /// True when the game can be completed without further input.
-    pub is_auto_completable: bool,
     /// Number of times `undo()` has been successfully invoked this game.
     pub undo_count: u32,
     /// Number of times the waste pile has been recycled back to stock this game.
@@ -195,14 +196,14 @@ pub struct GameState {
 
 impl PartialEq for GameState {
     fn eq(&self, other: &Self) -> bool {
-        self.draw_mode == other.draw_mode
+        self.draw_mode() == other.draw_mode()
             && self.mode == other.mode
             && self.score == other.score
-            && self.move_count == other.move_count
+            && self.move_count() == other.move_count()
             && self.elapsed_seconds == other.elapsed_seconds
             && self.seed == other.seed
-            && self.is_won == other.is_won
-            && self.is_auto_completable == other.is_auto_completable
+            && self.is_won() == other.is_won()
+            && self.is_auto_completable() == other.is_auto_completable()
             && self.undo_count == other.undo_count
             && self.recycle_count == other.recycle_count
             && self.take_from_foundation == other.take_from_foundation
@@ -225,7 +226,7 @@ impl Eq for GameState {}
 impl Serialize for GameState {
     fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
         PersistedGameState {
-            draw_mode: self.draw_mode,
+            draw_mode: self.draw_mode(),
             mode: self.mode,
             score: self.score,
             elapsed_seconds: self.elapsed_seconds,
@@ -256,14 +257,10 @@ impl<'de> Deserialize<'de> for GameState {
         }
 
         let mut game = Self {
-            draw_mode: persisted.draw_mode,
             mode: persisted.mode,
             score: persisted.score,
-            move_count: 0,
             elapsed_seconds: persisted.elapsed_seconds,
             seed: persisted.seed,
-            is_won: false,
-            is_auto_completable: false,
             undo_count: persisted.undo_count,
             // Rebuilt from the replay loop below; persisted value may be stale
             // due to the pre-Phase-3 undo drift bug.
@@ -282,7 +279,7 @@ impl<'de> Deserialize<'de> for GameState {
             test_pile_state: None,
         };
 
-        let replay_config = Self::replay_config(game.draw_mode);
+        let replay_config = Self::replay_config(persisted.draw_mode);
         for any in persisted.saved_moves {
             // AnyInstruction::V4 arrives directly from upstream serde (schema v4).
             // AnyInstruction::V3 was serialised with u8 indices (schema v3) and is
@@ -318,9 +315,6 @@ impl<'de> Deserialize<'de> for GameState {
             }
         }
 
-        game.move_count = Self::u32_from_len(game.session.history().len());
-        game.is_won = game.check_win();
-        game.is_auto_completable = !game.is_won && game.check_auto_complete();
         Ok(game)
     }
 }
@@ -334,14 +328,10 @@ impl GameState {
     /// Creates a new game with an explicit `GameMode`.
     pub fn new_with_mode(seed: u64, draw_mode: DrawMode, mode: GameMode) -> Self {
         Self {
-            draw_mode,
             mode,
             score: 0,
-            move_count: 0,
             elapsed_seconds: 0,
             seed,
-            is_won: false,
-            is_auto_completable: false,
             undo_count: 0,
             recycle_count: 0,
             take_from_foundation: true,
@@ -353,6 +343,51 @@ impl GameState {
         }
     }
 
+    /// Whether the player draws one or three cards from the stock per turn.
+    /// Derived from the underlying session config (set once at deal time).
+    pub fn draw_mode(&self) -> DrawMode {
+        match self.session.config().inner.draw_stock {
+            DrawStockConfig::DrawOne => DrawMode::DrawOne,
+            DrawStockConfig::DrawThree => DrawMode::DrawThree,
+        }
+    }
+
+    /// Total moves made this game (draws, recycles, and card moves), derived
+    /// from the session's instruction history length.
+    pub fn move_count(&self) -> u32 {
+        #[cfg(feature = "test-support")]
+        if let Some(ref state) = self.test_pile_state
+            && let Some(count) = state.move_count
+        {
+            return count;
+        }
+        Self::u32_from_len(self.session.history().len())
+    }
+
+    /// True once all 52 cards are on the foundations. No further moves are
+    /// accepted. Derived from the session win state.
+    pub fn is_won(&self) -> bool {
+        #[cfg(feature = "test-support")]
+        if let Some(ref state) = self.test_pile_state
+            && let Some(won) = state.won
+        {
+            return won;
+        }
+        self.check_win()
+    }
+
+    /// True when the game can be completed without further player input
+    /// (and is not already won). Derived from the session state.
+    pub fn is_auto_completable(&self) -> bool {
+        #[cfg(feature = "test-support")]
+        if let Some(ref state) = self.test_pile_state
+            && let Some(auto) = state.auto_completable
+        {
+            return auto;
+        }
+        !self.check_win() && self.check_auto_complete()
+    }
+
     fn new_session(seed: u64, draw_mode: DrawMode) -> Session<Klondike> {
         Session::new(Klondike::with_seed(seed), Self::session_config(draw_mode))
     }
@@ -375,7 +410,7 @@ impl GameState {
     }
 
     fn validation_config(&self) -> KlondikeConfig {
-        KlondikeAdapter::config_for(self.draw_mode, self.take_from_foundation)
+        KlondikeAdapter::config_for(self.draw_mode(), self.take_from_foundation)
     }
 
     /// Collects the session instruction history as upstream types for schema v4
@@ -529,6 +564,44 @@ impl GameState {
         self.test_pile_state = None;
     }
 
+    /// Test-support helper: re-deal the current seed under a different draw
+    /// mode. `draw_mode()` is otherwise fixed at deal time, so tests that need
+    /// a specific mode use this instead of mutating a field.
+    #[cfg(feature = "test-support")]
+    pub fn set_test_draw_mode(&mut self, draw_mode: DrawMode) {
+        self.session = Self::new_session(self.seed, draw_mode);
+    }
+
+    /// Test-support helper: override the value returned by [`Self::is_won`]
+    /// without driving the session to a genuine win.
+    #[cfg(feature = "test-support")]
+    pub fn set_test_won(&mut self, won: bool) {
+        let state = self
+            .test_pile_state
+            .get_or_insert_with(TestPileState::default);
+        state.won = Some(won);
+    }
+
+    /// Test-support helper: override the value returned by
+    /// [`Self::is_auto_completable`].
+    #[cfg(feature = "test-support")]
+    pub fn set_test_auto_completable(&mut self, auto_completable: bool) {
+        let state = self
+            .test_pile_state
+            .get_or_insert_with(TestPileState::default);
+        state.auto_completable = Some(auto_completable);
+    }
+
+    /// Test-support helper: override the value returned by
+    /// [`Self::move_count`] without applying real moves.
+    #[cfg(feature = "test-support")]
+    pub fn set_test_move_count(&mut self, move_count: u32) {
+        let state = self
+            .test_pile_state
+            .get_or_insert_with(TestPileState::default);
+        state.move_count = Some(move_count);
+    }
+
     /// Test-support helper: override face-down stock cards returned by
     /// [`Self::stock_cards`].
     #[cfg(feature = "test-support")]
@@ -623,7 +696,7 @@ impl GameState {
                     let next_count = self.recycle_count.saturating_add(1);
                     let penalty = KlondikeAdapter::score_for_recycle_with_mode(
                         next_count,
-                        self.draw_mode == DrawMode::DrawThree,
+                        self.draw_mode() == DrawMode::DrawThree,
                         self.mode,
                     );
                     (penalty, true)
@@ -800,7 +873,7 @@ impl GameState {
 
     /// Draw cards from stock to waste. When stock is empty, recycles waste back to stock.
     pub fn draw(&mut self) -> Result<(), MoveError> {
-        if self.is_won {
+        if self.is_won() {
             return Err(MoveError::GameAlreadyWon);
         }
 
@@ -823,7 +896,6 @@ impl GameState {
             self.recycle_count = self.recycle_count.saturating_add(1);
         }
         self.score = (self.score + score_delta).max(0);
-        self.move_count = Self::u32_from_len(self.session.history().len());
         Ok(())
     }
 
@@ -834,7 +906,7 @@ impl GameState {
         to: KlondikePile,
         count: usize,
     ) -> Result<(), MoveError> {
-        if self.is_won {
+        if self.is_won() {
             return Err(MoveError::GameAlreadyWon);
         }
         if from == to {
@@ -869,15 +941,12 @@ impl GameState {
 
         self.session.process_instruction(instruction);
         self.score = (self.score + score_delta).max(0);
-        self.move_count = Self::u32_from_len(self.session.history().len());
-        self.is_won = self.check_win();
-        self.is_auto_completable = !self.is_won && self.check_auto_complete();
         Ok(())
     }
 
     /// Restore the most recent undo snapshot and apply the undo score penalty (-15).
     pub fn undo(&mut self) -> Result<(), MoveError> {
-        if self.is_won {
+        if self.is_won() {
             return Err(MoveError::GameAlreadyWon);
         }
         if self.mode == GameMode::Challenge {
@@ -905,9 +974,6 @@ impl GameState {
         // This correctly reverses any recycle or move penalty that was applied
         // before adding the −15 undo penalty.
         self.score = KlondikeAdapter::apply_undo_score(pre_move_score, self.mode);
-        self.move_count = Self::u32_from_len(self.session.history().len());
-        self.is_won = self.check_win();
-        self.is_auto_completable = !self.is_won && self.check_auto_complete();
         self.undo_count = self.undo_count.saturating_add(1);
         Ok(())
     }
@@ -925,7 +991,7 @@ impl GameState {
 
     /// Returns all currently valid `(from, to, count)` moves.
     pub fn possible_instructions(&self) -> Vec<(KlondikePile, KlondikePile, usize)> {
-        if self.is_won {
+        if self.is_won() {
             return Vec::new();
         }
 
@@ -941,7 +1007,7 @@ impl GameState {
 
     /// Returns `true` when `move_cards(from, to, count)` would currently succeed.
     pub fn can_move_cards(&self, from: &KlondikePile, to: &KlondikePile, count: usize) -> bool {
-        if self.is_won || from == to {
+        if self.is_won() || from == to {
             return false;
         }
         let from_pile = self.pile(*from);
@@ -984,7 +1050,7 @@ impl GameState {
 
     /// Returns the next `(from, to)` move that advances auto-complete, or `None` if absent.
     pub fn next_auto_complete_move(&self) -> Option<(KlondikePile, KlondikePile)> {
-        if !self.is_auto_completable || self.is_won {
+        if !self.is_auto_completable() || self.is_won() {
             return None;
         }
 
diff --git a/solitaire_core/src/proptest_tests.rs b/solitaire_core/src/proptest_tests.rs
index b63ee75..c0a58aa 100644
--- a/solitaire_core/src/proptest_tests.rs
+++ b/solitaire_core/src/proptest_tests.rs
@@ -89,7 +89,7 @@ fn apply_random_actions(game: &mut GameState, actions: &[(bool, usize)]) {
 /// available), using `move_idx` to select among the legal options.
 /// Returns `true` when a move was successfully applied.
 fn apply_one_move(game: &mut GameState, move_idx: usize) -> bool {
-    if game.is_won {
+    if game.is_won() {
         return false;
     }
     let instructions = game.possible_instructions();
@@ -218,10 +218,10 @@ proptest! {
 
         // Snapshot the state before the move.
         let before_ids = all_cards(&game);
-        let before_move_count = game.move_count;
+        let before_move_count = game.move_count();
 
         // Apply one move.
-        if !apply_one_move(&mut game, move_idx) || game.is_won {
+        if !apply_one_move(&mut game, move_idx) || game.is_won() {
             return Ok(()); // nothing to undo
         }
 
@@ -236,7 +236,7 @@ proptest! {
             "pile layout after undo differs from the pre-move snapshot",
         );
         prop_assert_eq!(
-            game.move_count,
+            game.move_count(),
             before_move_count,
             "move_count after undo must equal the pre-move value",
         );
diff --git a/solitaire_data/Cargo.toml b/solitaire_data/Cargo.toml
index b1a65ce..89342e7 100644
--- a/solitaire_data/Cargo.toml
+++ b/solitaire_data/Cargo.toml
@@ -39,6 +39,7 @@ keyring-core   = { workspace = true }
 jni            = { workspace = true }
 
 [dev-dependencies]
+solitaire_core   = { workspace = true, features = ["test-support"] }
 solitaire_server = { path = "../solitaire_server" }
 solitaire_sync   = { workspace = true }
 axum             = { workspace = true }
diff --git a/solitaire_data/src/solver.rs b/solitaire_data/src/solver.rs
index 4f320da..2cc0204 100644
--- a/solitaire_data/src/solver.rs
+++ b/solitaire_data/src/solver.rs
@@ -93,7 +93,7 @@ fn solve_game_state(initial: &GameState, config: &SolverConfig) -> SolveOutcome
 
     // Preserve the historical payload contract: winnable verdicts always carry
     // a first move. An already-won state therefore returns no recommendation.
-    if initial.is_won {
+    if initial.is_won() {
         return SolveOutcome {
             result: SolverResult::Unwinnable,
             first_move: None,
@@ -101,7 +101,7 @@ fn solve_game_state(initial: &GameState, config: &SolverConfig) -> SolveOutcome
     }
 
     let solver_config = SessionConfig {
-        inner: KlondikeAdapter::config_for(initial.draw_mode, initial.take_from_foundation),
+        inner: KlondikeAdapter::config_for(initial.draw_mode(), initial.take_from_foundation),
         undo_penalty: 0,
         solve_moves_budget: config.move_budget,
         solve_states_budget: config.state_budget as u64,
diff --git a/solitaire_data/src/storage.rs b/solitaire_data/src/storage.rs
index 880cb0c..2938d5b 100644
--- a/solitaire_data/src/storage.rs
+++ b/solitaire_data/src/storage.rs
@@ -85,13 +85,13 @@ pub fn game_state_file_path() -> Option<PathBuf> {
 pub fn load_game_state_from(path: &Path) -> Option<GameState> {
     let data = fs::read(path).ok()?;
     let gs: GameState = serde_json::from_slice(&data).ok()?;
-    if gs.is_won { None } else { Some(gs) }
+    if gs.is_won() { None } else { Some(gs) }
 }
 
 /// Save an in-progress `GameState` atomically. Skips the write if `gs.is_won`
 /// because a completed game should not be resumed.
 pub fn save_game_state_to(path: &Path, gs: &GameState) -> io::Result<()> {
-    if gs.is_won {
+    if gs.is_won() {
         return Ok(());
     }
     if let Some(parent) = path.parent() {
@@ -386,8 +386,8 @@ mod tests {
 
         let loaded = load_game_state_from(&path).expect("load");
         assert_eq!(loaded.seed, gs.seed);
-        assert_eq!(loaded.draw_mode, gs.draw_mode);
-        assert!(!loaded.is_won);
+        assert_eq!(loaded.draw_mode(), gs.draw_mode());
+        assert!(!loaded.is_won());
     }
 
     #[test]
@@ -411,7 +411,7 @@ mod tests {
         let _ = fs::remove_file(&path);
 
         let mut gs = GameState::new(99, DrawMode::DrawOne);
-        gs.is_won = true;
+        gs.set_test_won(true);
         save_game_state_to(&path, &gs).expect("save should be no-op, not error");
         assert!(
             !path.exists(),
diff --git a/solitaire_engine/src/achievement_plugin.rs b/solitaire_engine/src/achievement_plugin.rs
index 4018c3e..4062c01 100644
--- a/solitaire_engine/src/achievement_plugin.rs
+++ b/solitaire_engine/src/achievement_plugin.rs
@@ -819,7 +819,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<GameStateResource>()
             .0
-            .draw_mode = solitaire_core::DrawMode::DrawThree;
+            .set_test_draw_mode(solitaire_core::DrawMode::DrawThree);
 
         app.world_mut().write_message(GameWonEvent {
             score: 500,
@@ -868,7 +868,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<GameStateResource>()
             .0
-            .draw_mode = solitaire_core::DrawMode::DrawThree;
+            .set_test_draw_mode(solitaire_core::DrawMode::DrawThree);
 
         app.world_mut().write_message(GameWonEvent {
             score: 500,
diff --git a/solitaire_engine/src/auto_complete_plugin.rs b/solitaire_engine/src/auto_complete_plugin.rs
index 882e194..5b50584 100644
--- a/solitaire_engine/src/auto_complete_plugin.rs
+++ b/solitaire_engine/src/auto_complete_plugin.rs
@@ -76,14 +76,14 @@ fn detect_auto_complete(
     }
     changed.clear();
 
-    if game.0.is_won {
+    if game.0.is_won() {
         state.active = false;
         return;
     }
-    if game.0.is_auto_completable && !state.active {
+    if game.0.is_auto_completable() && !state.active {
         state.active = true;
         state.cooldown = AUTO_COMPLETE_INITIAL_DELAY;
-    } else if !game.0.is_auto_completable && state.active {
+    } else if !game.0.is_auto_completable() && state.active {
         // `is_auto_completable` only becomes false after an explicit undo
         // (which puts a card back on the tableau or re-fills the stock/waste)
         // or a new-game reset — never as a transient gap during a normal
@@ -209,7 +209,7 @@ mod tests {
             Tableau::Tableau1,
             vec![solitaire_core::card::Card::new(Deck::Deck1, Suit::Clubs, Rank::Ace)],
         );
-        g.is_auto_completable = true;
+        g.set_test_auto_completable(true);
         let expected = (
             KlondikePile::Tableau(Tableau::Tableau1),
             KlondikePile::Foundation(Foundation::Foundation1),
@@ -228,7 +228,7 @@ mod tests {
     fn detect_activates_when_auto_completable() {
         let mut app = headless_app();
         let mut g = GameState::new(42, DrawMode::DrawOne);
-        g.is_auto_completable = true;
+        g.set_test_auto_completable(true);
         app.world_mut().resource_mut::<GameStateResource>().0 = g;
         app.world_mut().write_message(StateChangedEvent);
         app.update();
@@ -263,7 +263,7 @@ mod tests {
         let mut app = headless_app();
         // Inject a won game state — active should not be set.
         let (mut gs, _) = seeded_state_with_auto_move();
-        gs.is_won = true;
+        gs.set_test_won(true);
         app.world_mut().resource_mut::<GameStateResource>().0 = gs;
         app.world_mut().write_message(StateChangedEvent);
         app.update();
diff --git a/solitaire_engine/src/card_plugin.rs b/solitaire_engine/src/card_plugin.rs
index dc0a75d..e9218c6 100644
--- a/solitaire_engine/src/card_plugin.rs
+++ b/solitaire_engine/src/card_plugin.rs
@@ -734,7 +734,7 @@ fn sync_cards(
     // Without this, the buffer sits at waste_base uncovered during the animation
     // and its rank/suit peek behind the incoming card.
     let waste_buffer_id: Option<Card> = {
-        let visible = match game.draw_mode {
+        let visible = match game.draw_mode() {
             DrawMode::DrawOne => 1_usize,
             DrawMode::DrawThree => 3_usize,
         };
@@ -903,7 +903,7 @@ fn card_positions(game: &GameState, layout: &Layout) -> Vec<((Card, bool), Vec2,
         // while new cards animate in from the stock. Draw-One shows 1; Draw-Three
         // shows up to 3 fanned in X (matching the standard Klondike presentation).
         let render_start = if is_waste {
-            let visible = match game.draw_mode {
+            let visible = match game.draw_mode() {
                 DrawMode::DrawOne => 1_usize,
                 DrawMode::DrawThree => 3_usize,
             };
@@ -918,7 +918,7 @@ fn card_positions(game: &GameState, layout: &Layout) -> Vec<((Card, bool), Vec2,
         let mut y_offset = 0.0_f32;
         let rendered_len = cards[render_start..].len();
         for (slot, (card, face_up)) in cards[render_start..].iter().enumerate() {
-            let x_offset = if is_waste && matches!(game.draw_mode, DrawMode::DrawThree) {
+            let x_offset = if is_waste && matches!(game.draw_mode(), DrawMode::DrawThree) {
                 // When len > visible, slot 0 is a hidden buffer card kept at
                 // x=0 to prevent a flash during the draw tween. When len ≤
                 // visible (small pile), every card is visible and should fan
diff --git a/solitaire_engine/src/cursor_plugin.rs b/solitaire_engine/src/cursor_plugin.rs
index c0f0038..2b0ff86 100644
--- a/solitaire_engine/src/cursor_plugin.rs
+++ b/solitaire_engine/src/cursor_plugin.rs
@@ -437,7 +437,7 @@ fn tableau_or_stack_pos(
             base.x,
             base.y - layout.card_size.y * layout.tableau_fan_frac * (index as f32),
         )
-    } else if matches!(pile, KlondikePile::Stock) && game.draw_mode == DrawMode::DrawThree {
+    } else if matches!(pile, KlondikePile::Stock) && game.draw_mode() == DrawMode::DrawThree {
         let pile_len = game.waste_cards().len();
         let visible_start = pile_len.saturating_sub(3);
         let slot = index.saturating_sub(visible_start) as f32;
diff --git a/solitaire_engine/src/feedback_anim_plugin.rs b/solitaire_engine/src/feedback_anim_plugin.rs
index bcb2f24..a168a28 100644
--- a/solitaire_engine/src/feedback_anim_plugin.rs
+++ b/solitaire_engine/src/feedback_anim_plugin.rs
@@ -408,7 +408,7 @@ fn start_deal_anim(
         return;
     }
     // Only animate a fresh deal (no moves made yet).
-    if game.0.move_count != 0 {
+    if game.0.move_count() != 0 {
         return;
     }
     let Some(layout) = layout else { return };
diff --git a/solitaire_engine/src/game_plugin.rs b/solitaire_engine/src/game_plugin.rs
index 0f3ed05..837b58d 100644
--- a/solitaire_engine/src/game_plugin.rs
+++ b/solitaire_engine/src/game_plugin.rs
@@ -154,7 +154,7 @@ impl Plugin for GamePlugin {
         let saved = path.as_deref().and_then(load_game_state_from);
         let prompt_worthy = saved
             .as_ref()
-            .is_some_and(|g| g.move_count > 0 && !g.is_won);
+            .is_some_and(|g| g.move_count() > 0 && !g.is_won());
         let (initial_state, pending_restore) = if prompt_worthy {
             (
                 GameState::new(seed_from_system_time(), DrawMode::DrawOne),
@@ -302,7 +302,7 @@ fn tick_elapsed_time(
         *skip_next_delta = false;
         return;
     }
-    let is_won = game.0.is_won;
+    let is_won = game.0.is_won();
     advance_elapsed(
         &mut game.0.elapsed_seconds,
         &mut accumulator,
@@ -424,7 +424,7 @@ fn handle_new_game(
     for ev in new_game.read() {
         // If an active game is in progress, intercept and show a confirm dialog.
         // A game is "active" when moves have been made and it is not yet won.
-        let needs_confirm = game.0.move_count > 0 && !game.0.is_won;
+        let needs_confirm = game.0.move_count() > 0 && !game.0.is_won();
         // Skip confirmation if a ConfirmNewGameScreen already exists (prevents
         // duplicates) or if the event itself was already confirmed by the
         // player pressing Y on the modal — without the `confirmed` check the
@@ -464,7 +464,7 @@ fn handle_new_game(
         // where SettingsPlugin is not installed.
         let draw_mode = settings
             .as_ref()
-            .map_or_else(|| game.0.draw_mode, |s| s.0.draw_mode);
+            .map_or_else(|| game.0.draw_mode(), |s| s.0.draw_mode);
         let mode = ev.mode.unwrap_or(game.0.mode);
 
         // Solver-backed retry: when the player has opted in to
@@ -823,7 +823,7 @@ fn handle_draw(
             if stock.is_empty() {
                 Vec::new()
             } else {
-                let draw_count = match game.0.draw_mode {
+                let draw_count = match game.0.draw_mode() {
                     DrawMode::DrawOne => 1_usize,
                     DrawMode::DrawThree => 3_usize,
                 };
@@ -865,7 +865,7 @@ fn handle_move(
     path: Option<Res<GameStatePath>>,
 ) {
     for ev in moves.read() {
-        let was_won = game.0.is_won;
+        let was_won = game.0.is_won();
         // Identify the card that will be exposed (and may flip face-up) by the move.
         // It's the card just below the bottom of the moving stack in the source pile.
         let source_cards = pile_cards(&game.0, &ev.from);
@@ -910,7 +910,7 @@ fn handle_move(
                     foundation_done.write(FoundationCompletedEvent { slot, suit });
                 }
                 changed.write(StateChangedEvent);
-                if !was_won && game.0.is_won {
+                if !was_won && game.0.is_won() {
                     won.write(GameWonEvent {
                         score: game.0.score,
                         time_seconds: game.0.elapsed_seconds,
@@ -986,7 +986,7 @@ pub fn record_replay_on_win(
         let win_move_index = recording.moves.len().checked_sub(1);
         let replay = Replay::new(
             game.0.seed,
-            game.0.draw_mode,
+            game.0.draw_mode(),
             game.0.mode,
             ev.time_seconds,
             ev.score,
@@ -1093,13 +1093,13 @@ fn check_no_moves(
 
     // Despawn game-over overlay whenever moves become available again or game is won.
     let moves_ok = has_legal_moves(&game.0);
-    if moves_ok || game.0.is_won {
+    if moves_ok || game.0.is_won() {
         for entity in &game_over_screens {
             commands.entity(entity).despawn();
         }
     }
 
-    if game.0.is_won {
+    if game.0.is_won() {
         return;
     }
 
@@ -1248,7 +1248,7 @@ fn auto_save_game_state(
     // or there's a pending restore the player hasn't answered — saving
     // the fresh-deal placeholder we seeded GameStateResource with at
     // startup would clobber the real saved game on disk.
-    if paused.is_some_and(|p| p.0) || game.0.is_won || game.0.move_count == 0 || pending.0.is_some()
+    if paused.is_some_and(|p| p.0) || game.0.is_won() || game.0.move_count() == 0 || pending.0.is_some()
     {
         return;
     }
@@ -1596,7 +1596,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<GameStateResource>()
             .0
-            .move_count = 1;
+            .set_test_move_count(1);
 
         // Re-arm the timer past the threshold every frame and pump
         // updates until the save fires. Caps at 16 iterations — a
@@ -1845,7 +1845,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<GameStateResource>()
             .0
-            .move_count = 5;
+            .set_test_move_count(5);
         app.world_mut().write_message(NewGameRequestEvent {
             seed: None,
             mode: None,
@@ -1869,7 +1869,7 @@ mod tests {
         let mut app = test_app_with_input(42);
         // move_count stays at 0 (fresh game).
         assert_eq!(
-            app.world().resource::<GameStateResource>().0.move_count,
+            app.world().resource::<GameStateResource>().0.move_count(),
             0,
             "test assumes a fresh game with no moves"
         );
@@ -2362,7 +2362,7 @@ mod tests {
         app.update();
 
         // Game state was reseeded — move_count is 0 on the new game.
-        assert_eq!(app.world().resource::<GameStateResource>().0.move_count, 0);
+        assert_eq!(app.world().resource::<GameStateResource>().0.move_count(), 0);
     }
 
     #[test]
@@ -2436,7 +2436,7 @@ mod tests {
         // The chosen seed is non-deterministic (system time),
         // but the new game must have been started cleanly:
         // move_count back to 0, undo stack empty.
-        assert_eq!(app.world().resource::<GameStateResource>().0.move_count, 0);
+        assert_eq!(app.world().resource::<GameStateResource>().0.move_count(), 0);
         assert_eq!(
             app.world()
                 .resource::<GameStateResource>()
@@ -2496,7 +2496,7 @@ mod tests {
         );
         // New game completed: a fresh deal carries 0 moves.
         assert_eq!(
-            app.world().resource::<GameStateResource>().0.move_count,
+            app.world().resource::<GameStateResource>().0.move_count(),
             0,
             "completed new game must be in fresh-deal state",
         );
diff --git a/solitaire_engine/src/hud_plugin.rs b/solitaire_engine/src/hud_plugin.rs
index fe2fe58..1d68ec8 100644
--- a/solitaire_engine/src/hud_plugin.rs
+++ b/solitaire_engine/src/hud_plugin.rs
@@ -1154,7 +1154,7 @@ fn handle_hint_button(
             return;
         }
         let Some(ref g) = game else { return };
-        if g.0.is_won {
+        if g.0.is_won() {
             info_toast.write(InfoToastEvent(HINT_WON_MSG.to_string()));
             return;
         }
@@ -2106,10 +2106,10 @@ fn update_won_previously(
     let Ok(mut text) = q.single_mut() else {
         return;
     };
-    let won_before = !game.0.is_won
+    let won_before = !game.0.is_won()
         && history.as_ref().is_some_and(|h| {
             h.0.replays.iter().any(|r| {
-                r.seed == game.0.seed && r.draw_mode == game.0.draw_mode && r.mode == game.0.mode
+                r.seed == game.0.seed && r.draw_mode == game.0.draw_mode() && r.mode == game.0.mode
             })
         });
     let next = if won_before {
@@ -2279,11 +2279,11 @@ fn update_hud(
             };
         }
         if let Ok(mut t) = moves_q.single_mut() {
-            **t = format!("Moves: {}", g.move_count);
+            **t = format!("Moves: {}", g.move_count());
         }
         if let Ok(mut t) = mode_q.single_mut() {
             **t = match g.mode {
-                GameMode::Classic => match g.draw_mode {
+                GameMode::Classic => match g.draw_mode() {
                     DrawMode::DrawOne => String::new(),
                     DrawMode::DrawThree => "Draw 3".to_string(),
                 },
@@ -2296,7 +2296,7 @@ fn update_hud(
 
         // --- Daily challenge constraint (with time-low colour warning) ---
         if let Ok((mut t, mut color)) = challenge_q.single_mut() {
-            if g.is_won {
+            if g.is_won() {
                 **t = String::new();
             } else if let Some(dc) = daily.as_deref() {
                 **t = challenge_hud_text(dc);
@@ -2334,7 +2334,7 @@ fn update_hud(
 
         // --- Draw-cycle indicator (Draw-Three mode only) ---
         if let Ok(mut t) = draw_cycle_q.single_mut() {
-            **t = if g.is_won || g.draw_mode != DrawMode::DrawThree {
+            **t = if g.is_won() || g.draw_mode() != DrawMode::DrawThree {
                 // Hide when not in Draw-Three or after the game is won.
                 String::new()
             } else {
@@ -2774,7 +2774,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<GameStateResource>()
             .0
-            .move_count = 42;
+            .set_test_move_count(42);
         app.update();
         assert_eq!(read_hud_text::<HudMoves>(&mut app), "Moves: 42");
     }
@@ -2962,7 +2962,7 @@ mod tests {
             max_time_secs: Some(300),
         });
         // Mark the game as won — HudChallenge should be empty.
-        app.world_mut().resource_mut::<GameStateResource>().0.is_won = true;
+        app.world_mut().resource_mut::<GameStateResource>().0.set_test_won(true);
         app.update();
         assert_eq!(read_hud_text::<HudChallenge>(&mut app), "");
     }
@@ -3012,7 +3012,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<GameStateResource>()
             .0
-            .move_count += 1;
+            .set_test_move_count(1);
         app.update();
         assert_eq!(read_hud_text::<HudAutoComplete>(&mut app), "AUTO");
     }
@@ -3024,7 +3024,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<GameStateResource>()
             .0
-            .move_count += 1;
+            .set_test_move_count(1);
         app.update();
         assert_eq!(read_hud_text::<HudAutoComplete>(&mut app), "");
     }
diff --git a/solitaire_engine/src/input_plugin.rs b/solitaire_engine/src/input_plugin.rs
index 266cf1e..2904e0b 100644
--- a/solitaire_engine/src/input_plugin.rs
+++ b/solitaire_engine/src/input_plugin.rs
@@ -305,7 +305,7 @@ fn handle_keyboard_hint(
 
     let Some(ref g) = game else { return };
 
-    if g.0.is_won {
+    if g.0.is_won() {
         info_toast.write(InfoToastEvent(
             "Game won! Press N for a new game".to_string(),
         ));
@@ -1153,7 +1153,7 @@ fn card_position(
             y_offset -= layout.card_size.y * step;
         }
         Vec2::new(base.x, base.y + y_offset)
-    } else if matches!(pile, KlondikePile::Stock) && game.draw_mode == DrawMode::DrawThree {
+    } else if matches!(pile, KlondikePile::Stock) && game.draw_mode() == DrawMode::DrawThree {
         // In Draw-Three mode the top 3 waste cards are fanned in X to match
         // card_plugin::card_positions(). Hit-testing must use the same offsets
         // so clicking the visually rightmost (top) card actually registers.
diff --git a/solitaire_engine/src/pause_plugin.rs b/solitaire_engine/src/pause_plugin.rs
index 0d79e51..4a38976 100644
--- a/solitaire_engine/src/pause_plugin.rs
+++ b/solitaire_engine/src/pause_plugin.rs
@@ -340,7 +340,7 @@ fn handle_forfeit_request(
     if !forfeit_screens.is_empty() {
         return;
     }
-    let game_in_progress = game.as_ref().is_some_and(|g| !g.0.is_won);
+    let game_in_progress = game.as_ref().is_some_and(|g| !g.0.is_won());
     if !game_in_progress {
         toast.write(InfoToastEvent("No game to forfeit".to_string()));
         return;
@@ -1025,7 +1025,7 @@ mod tests {
         app.add_plugins(MinimalPlugins).add_plugins(PausePlugin);
         app.init_resource::<ButtonInput<KeyCode>>();
         let mut game = GameState::new(1, DrawMode::DrawOne);
-        game.is_won = true;
+        game.set_test_won(true);
         app.insert_resource(GameStateResource(game));
         app.update();
 
diff --git a/solitaire_engine/src/pending_hint.rs b/solitaire_engine/src/pending_hint.rs
index c753c9f..01272a9 100644
--- a/solitaire_engine/src/pending_hint.rs
+++ b/solitaire_engine/src/pending_hint.rs
@@ -63,7 +63,7 @@ impl PendingHintTask {
     /// Spawn a new solver task for `state` with `config`. Drops any
     /// previously in-flight task first (cancel-on-replace).
     pub fn spawn(&mut self, state: GameState, config: SolverConfig) {
-        let move_count_at_spawn = state.move_count;
+        let move_count_at_spawn = state.move_count();
         let handle = AsyncComputeTaskPool::get().spawn(async move {
             let outcome = try_solve_from_state(&state, &config);
             match outcome.result {
@@ -156,7 +156,7 @@ pub fn poll_pending_hint_task(
     pending.inner = None;
 
     let Some(g) = game else { return };
-    if g.0.move_count != move_count_at_spawn {
+    if g.0.move_count() != move_count_at_spawn {
         return;
     }
 
diff --git a/solitaire_engine/src/stats_plugin.rs b/solitaire_engine/src/stats_plugin.rs
index dd6aed5..834a8b8 100644
--- a/solitaire_engine/src/stats_plugin.rs
+++ b/solitaire_engine/src/stats_plugin.rs
@@ -534,7 +534,7 @@ fn update_stats_on_win(
     let prev_streak = stats.0.win_streak_current;
     stats
         .0
-        .update_on_win(ev.score, ev.time_seconds, &game.0.draw_mode);
+        .update_on_win(ev.score, ev.time_seconds, &game.0.draw_mode());
     // Per-mode best score / fastest win — additive on top of the
     // lifetime totals tracked by `update_on_win`. TimeAttack is a
     // no-op inside the helper because it has its own session-level
@@ -588,7 +588,7 @@ fn update_stats_on_new_game(
     mut toast: MessageWriter<InfoToastEvent>,
 ) {
     for _ in events.read() {
-        if game.0.move_count > 0 && !game.0.is_won {
+        if game.0.move_count() > 0 && !game.0.is_won() {
             let streak = stats.0.win_streak_current;
             stats.0.record_abandoned();
             persist(&path, &stats.0, "abandoned game");
@@ -614,7 +614,7 @@ fn handle_forfeit(
     mut auto_complete: Option<ResMut<AutoCompleteState>>,
 ) {
     for _ in events.read() {
-        if game.0.move_count > 0 && !game.0.is_won {
+        if game.0.move_count() > 0 && !game.0.is_won() {
             let streak = stats.0.win_streak_current;
             stats.0.record_abandoned();
             persist(&path, &stats.0, "forfeit");
@@ -1327,7 +1327,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<crate::resources::GameStateResource>()
             .0
-            .draw_mode = solitaire_core::DrawMode::DrawThree;
+            .set_test_draw_mode(solitaire_core::DrawMode::DrawThree);
 
         app.world_mut().write_message(GameWonEvent {
             score: 500,
@@ -1373,7 +1373,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<crate::resources::GameStateResource>()
             .0
-            .move_count = 3;
+            .set_test_move_count(3);
 
         app.world_mut().write_message(NewGameRequestEvent {
             seed: Some(999),
@@ -1699,7 +1699,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<crate::resources::GameStateResource>()
             .0
-            .move_count = 1;
+            .set_test_move_count(1);
 
         app.world_mut().write_message(ForfeitEvent);
         app.update();
@@ -1725,7 +1725,7 @@ mod tests {
         app.world_mut()
             .resource_mut::<crate::resources::GameStateResource>()
             .0
-            .move_count = 1;
+            .set_test_move_count(1);
 
         app.world_mut().write_message(ForfeitEvent);
         app.update();
diff --git a/solitaire_engine/src/sync_plugin.rs b/solitaire_engine/src/sync_plugin.rs
index c978e96..64f7814 100644
--- a/solitaire_engine/src/sync_plugin.rs
+++ b/solitaire_engine/src/sync_plugin.rs
@@ -331,7 +331,7 @@ fn push_replay_on_win(
         }
         let replay = Replay::new(
             game.0.seed,
-            game.0.draw_mode,
+            game.0.draw_mode(),
             game.0.mode,
             ev.time_seconds,
             ev.score,
diff --git a/solitaire_engine/src/time_attack_plugin.rs b/solitaire_engine/src/time_attack_plugin.rs
index 68edc66..97a8910 100644
--- a/solitaire_engine/src/time_attack_plugin.rs
+++ b/solitaire_engine/src/time_attack_plugin.rs
@@ -182,7 +182,7 @@ fn advance_time_attack(
     // No shared screen-state enum currently covers every overlay. Pause the
     // countdown whenever gameplay is blocked by a modal, the pause flag, or a
     // just-won board state.
-    if paused.is_some_and(|p| p.0) || game.0.is_won || !modal_scrims.is_empty() {
+    if paused.is_some_and(|p| p.0) || game.0.is_won() || !modal_scrims.is_empty() {
         return;
     }
     session.remaining_secs = (session.remaining_secs - time.delta_secs()).max(0.0);
diff --git a/solitaire_engine/src/weekly_goals_plugin.rs b/solitaire_engine/src/weekly_goals_plugin.rs
index ca5cce3..40ae69e 100644
--- a/solitaire_engine/src/weekly_goals_plugin.rs
+++ b/solitaire_engine/src/weekly_goals_plugin.rs
@@ -83,7 +83,7 @@ fn evaluate_weekly_goals(
         let ctx = WeeklyGoalContext {
             time_seconds: ev.time_seconds,
             used_undo: game.0.undo_count > 0,
-            draw_mode: game.0.draw_mode,
+            draw_mode: game.0.draw_mode(),
         };
         for def in WEEKLY_GOALS {
             if !def.matches(&ctx) {
diff --git a/solitaire_wasm/src/lib.rs b/solitaire_wasm/src/lib.rs
index bb24d4a..70d895b 100644
--- a/solitaire_wasm/src/lib.rs
+++ b/solitaire_wasm/src/lib.rs
@@ -194,8 +194,8 @@ impl ReplayPlayer {
             step_idx: self.step_idx,
             total_steps: self.moves.len(),
             score: self.game.score,
-            move_count: self.game.move_count,
-            is_won: self.game.is_won,
+            move_count: self.game.move_count(),
+            is_won: self.game.is_won(),
             stock: self
                 .game
                 .stock_cards()
@@ -359,7 +359,7 @@ fn pile_name(pile: KlondikePile) -> String {
 }
 
 fn can_stock_click(game: &GameState) -> bool {
-    !(game.is_won || game.stock_cards().is_empty() && game.waste_cards().is_empty())
+    !(game.is_won() || game.stock_cards().is_empty() && game.waste_cards().is_empty())
 }
 
 fn legal_moves_for_game(game: &GameState) -> Vec<DebugMove> {
@@ -450,7 +450,7 @@ fn invariant_report_for_game(game: &GameState, legal_moves: &[DebugMove]) -> Deb
         false
     });
 
-    let soft_lock = !game.is_won && stock.is_empty() && waste.is_empty() && legal_moves.is_empty();
+    let soft_lock = !game.is_won() && stock.is_empty() && waste.is_empty() && legal_moves.is_empty();
 
     let state_ok = duplicate_card_ids.is_empty()
         && missing_card_ids.is_empty()
@@ -496,9 +496,9 @@ impl SolitaireGame {
         };
         GameSnapshot {
             score: self.game.score,
-            move_count: self.game.move_count,
-            is_won: self.game.is_won,
-            is_auto_completable: self.game.is_auto_completable,
+            move_count: self.game.move_count(),
+            is_won: self.game.is_won(),
+            is_auto_completable: self.game.is_auto_completable(),
             has_moves,
             undo_count: self.game.undo_count,
             undo_stack_len: self.game.undo_stack_len(),
@@ -582,7 +582,7 @@ impl SolitaireGame {
 
     fn replay_moves_native(&self) -> Result<Vec<ReplayMove>, String> {
         let mut replay_game =
-            GameState::new_with_mode(self.game.seed, self.game.draw_mode, self.game.mode);
+            GameState::new_with_mode(self.game.seed, self.game.draw_mode(), self.game.mode);
         let mut replay_moves = Vec::new();
 
         for instruction in self.game.instruction_history() {
@@ -668,7 +668,7 @@ impl SolitaireGame {
         let state_json = serde_json::to_string(&self.game).unwrap_or_default();
         DebugSnapshot {
             seed: self.game.seed,
-            draw_mode: self.game.draw_mode,
+            draw_mode: self.game.draw_mode(),
             mode: self.game.mode,
             state: self.snap(),
             legal_moves,
@@ -822,7 +822,7 @@ impl SolitaireGame {
     /// waste by calling `draw()` so the next step can try again. Returns the
     /// post-move snapshot, or `null` when no progress is possible.
     pub fn auto_complete_step(&mut self) -> JsValue {
-        if !self.game.is_auto_completable {
+        if !self.game.is_auto_completable() {
             return JsValue::NULL;
         }
         if let Some((from, to)) = self.game.next_auto_complete_move() {