diff --git a/cardkit-server/src/main/kotlin/io/github/rotundtapir/cardkit/server/GameDescriptor.kt b/cardkit-server/src/main/kotlin/io/github/rotundtapir/cardkit/server/GameDescriptor.kt
index a721c30..50960ab 100644
--- a/cardkit-server/src/main/kotlin/io/github/rotundtapir/cardkit/server/GameDescriptor.kt
+++ b/cardkit-server/src/main/kotlin/io/github/rotundtapir/cardkit/server/GameDescriptor.kt
@@ -52,12 +52,17 @@ interface GameDescriptor<S : Any, A : Any, V : Any, C : Any> {
     val botNames: List<String> get() = DEFAULT_BOT_NAMES
 
     /**
-     * A fresh bot strategy for this room. Called once per room and shared by every bot-played seat,
-     * each with its own seeded [kotlin.random.Random], so the strategy must be stateless.
+     * A fresh bot strategy for this room's [config]. Called once per room and shared by every
+     * bot-played seat, each with its own seeded [kotlin.random.Random], so the strategy must be
+     * stateless.
+     *
+     * Takes the config because a bot is a function of the rules it plays under: a house rule that
+     * adds a card or a bid changes what a correct move is, and a bot built for the wrong ruleset
+     * misplays rather than failing loudly.
      *
      * Prefer a cheap heuristic bot: it runs on the server's single vCPU for every abandoned seat.
      */
-    fun bot(): Strategy<V, A>
+    fun bot(config: C): Strategy<V, A>
 
     /** The rules for a lobby's negotiated [config] — the game's house-rule toggles applied. */
     fun rulesFor(config: C): GameRules<S, A, V>
diff --git a/cardkit-server/src/main/kotlin/io/github/rotundtapir/cardkit/server/Room.kt b/cardkit-server/src/main/kotlin/io/github/rotundtapir/cardkit/server/Room.kt
index 2a6e43a..496f308 100644
--- a/cardkit-server/src/main/kotlin/io/github/rotundtapir/cardkit/server/Room.kt
+++ b/cardkit-server/src/main/kotlin/io/github/rotundtapir/cardkit/server/Room.kt
@@ -65,10 +65,13 @@ class Room<S : Any, A : Any, V : Any, C : Any>(
 ) {
     private val logger = LoggerFactory.getLogger("room")
     private val commands = Channel<RoomCommand<S, A>>(Channel.UNLIMITED)
-    private val bot: Strategy<V, A> = descriptor.bot()
 
     private var lobbyConfig = initialConfig
 
+    // Built from the config the room was created with. Only the timeouts can change later
+    // (RoomCommand.Configure), never the house rules, so the bot never goes stale.
+    private val bot: Strategy<V, A> = descriptor.bot(initialConfig)
+
     // Read cross-thread (isPlaying/resumedState from the Ktor handler & /health), written on the actor.
     @Volatile
     private var phase = RoomPhase.LOBBY
diff --git a/cardkit-server/src/test/kotlin/io/github/rotundtapir/cardkit/server/ToyGame.kt b/cardkit-server/src/test/kotlin/io/github/rotundtapir/cardkit/server/ToyGame.kt
index a5ef10a..01f1753 100644
--- a/cardkit-server/src/test/kotlin/io/github/rotundtapir/cardkit/server/ToyGame.kt
+++ b/cardkit-server/src/test/kotlin/io/github/rotundtapir/cardkit/server/ToyGame.kt
@@ -110,7 +110,7 @@ object ToyDescriptor : GameDescriptor<ToyState, ToyAction, ToyView, ToyConfig> {
     override val stateSerializer = ToyState.serializer()
     override val configSerializer = ToyConfig.serializer()
 
-    override fun bot(): Strategy<ToyView, ToyAction> =
+    override fun bot(config: ToyConfig): Strategy<ToyView, ToyAction> =
         Strategy { view, random -> view.legalActions.ifEmpty { listOf(ToyAction.Move(1)) }.random(random) }
 
     override fun rulesFor(config: ToyConfig): GameRules<ToyState, ToyAction, ToyView> = ToyRules(config.target)