add a floor

src/main/cpp/net/eagle0/common/mcts/abstract/AbstractMCTSAI.cpp

@@ -374,10 +374,10 @@ auto AbstractMCTSAI::MCTSExpansion(MCTSNode* node, const MCTSGameEngine& engine)
         // Get outcome information from engine
         const auto outcomeInfo = engine.getBinaryOutcomeInfo(*node->gameState, *action);
 
-        // Set up outcome metadata (2 outcomes for binary actions)
+        // Set up outcome metadata
         chanceNode->outcomeProbabilities = outcomeInfo.getProbabilities();
         chanceNode->outcomeRolls = outcomeInfo.getRepresentativeRolls();
-        chanceNode->totalActions = 2;  // Binary: success and failure
+        chanceNode->totalActions = chanceNode->outcomeProbabilities.size();
 
         // Chance node immediate score will be computed as expected value during backpropagation
         // For now, initialize to parent's score as a reasonable default

src/main/cpp/net/eagle0/shardok/library/FireUtils.cpp

@@ -71,10 +71,11 @@ auto GetFireDamage(
         const double openEndedPercentileRoll1,
         const double openEndedPercentileRoll2) -> CombatDamage {
     double randomSwing = 1.0 + (2 * openEndedPercentileRoll1 - 100.0) * RANDOMNESS_FACTOR / 100.0;
-    const double basicDamage = BASE_FIRE_DAMAGE_PER_TROOP * randomSwing * troops;
+    const double basicDamage = std::max(0.0, BASE_FIRE_DAMAGE_PER_TROOP * randomSwing * troops);
 
     randomSwing = 1.0 + (2 * openEndedPercentileRoll2 - 100.0) * RANDOMNESS_FACTOR / 100.0;
-    const double penetratingDamage = BASE_PENETRATING_FIRE_DAMAGE_PER_TROOP * randomSwing * troops;
+    const double penetratingDamage =
+            std::max(0.0, BASE_PENETRATING_FIRE_DAMAGE_PER_TROOP * randomSwing * troops);
 
     return CombatDamage::Builder()
             .SetFire(basicDamage)

src/main/cpp/net/eagle0/shardok/library/action_factories/PlayerSetupCommandFactory.cpp

@@ -4,6 +4,7 @@
 
 #include "PlayerSetupCommandFactory.hpp"
 
+#include "src/main/cpp/net/eagle0/shardok/library/ShardokException.hpp"
 #include "src/main/cpp/net/eagle0/shardok/library/actions/EndPlayerSetupCommand.hpp"
 #include "src/main/cpp/net/eagle0/shardok/library/actions/PlaceHiddenUnitCommand.hpp"
 #include "src/main/cpp/net/eagle0/shardok/library/actions/PlaceUnitCommand.hpp"
@@ -20,6 +21,15 @@ auto PlayerSetupCommandFactory::AddAvailablePlaceAndHideUnitCommandsForOneUnit(
         const bool isDefender,
         const Unit *unit,
         const GameStateW &gameState) const -> void {
+    // Attackers must have a valid starting_position_index (>= 0)
+    // Defenders use -1 since they share a single starting positions list
+    if (!isDefender && unit->starting_position_index() < 0) {
+        throw ShardokInternalErrorException(
+                "Attacker unit " + std::to_string(unit->unit_id()) +
+                " has invalid starting_position_index: " +
+                std::to_string(unit->starting_position_index()));
+    }
+
     const auto &thisUnitStartingPositions =
             (isDefender ? gameState->hex_map()->defender_starting_positions()
                         : gameState->hex_map()->attacker_starting_positions()->Get(