docs/HANDOFF.md records the completed engine, card coverage, replay, stress results, key files, decisions, remaining server/meta/client work and the pitfalls found during development. README links to it.
GameInvariants checks card counts, unique instance ids and damage. The CLI stress command runs random legal bot games and fails on the first violation. It exposed a real bug: an optional OnGuard ability that could not be paid (or was declined) reset the step from Guard to None while the battle was still open. OfferAbility now reports Skipped/Paused/Resolved and callers continue only when needed. 1000/1000 games finish with no errors.
Normal units can no longer attack the back row; Wyvern Strike, Tejas attacks the back row of its own column. Demonic Dragon Berserker, Yaksha rides itself from hand when an opponent's rear-guard is retired during the main phase. Match replay: CommandCodec, MatchRecord, MatchRecorder, ReplayRunner and an FNV event hash; a JSON round-trip replays a full bot game bit-for-bit. Three tests; 116 total.
GameEngine.LegalCommands returns every meaningful command for the current phase, pending trigger, ability, order or choice. A random bot plays 50 deterministic games and checks that each player always has 50 cards across zones, instance ids stay unique and damage never exceeds six. Fixes found by the bot: search-to-call no longer loses a card when there is no empty circle (InTransit), a stand trigger with no rear-guards can resolve, unpayable optional abilities no longer stall the order, and legal intents skip impossible retire-self and repeated intercept commands.
New triggers: OnBoostedHit, OnRetireFromRC, OnOpponentRetire, OnGuard; activated abilities from hand and drop zone; superior ride from drop. Cards: Voidmaster, Hagakure, Dreadmaster, Monster Frank, Blightops, Llew, Dragon Knight Aleph, Gancelot hand effect, Deathrex second effect, Brigitte, Bors, Tristan, Starlight Unicorn, Goku, Berserk Dragon, Aermo, Joka, Rakshasa. Four tests; 111 total.
Asura Kaiser reacts to grade 3 Nova Grappler drive checks; Rock the Wall and Redshoe Milly move from the guardian circle to soul; Juggernaut and Brakki return to deck after battle; Lozenge and Battleraizer return at end of turn; Guiding Zombie puts itself into soul and mills three. Four tests; 102 total.
Two files were rewritten with Get-Content/Set-Content and lost their UTF-8 encoding. Restored the clean versions and re-applied the changes with an encoding-safe editor.
AskUnitMultiChoice asks one target at a time, offers Done once the minimum is met and resolves automatically at the maximum. CardRestriction models cannot-stand/attack/boost/intercept with source, effect id and duration, including UntilOwnerNextStand. Restraint can be overridden by effects. OnAttackHit now fires when the attack hits a rear-guard. Five tests.
StatModifier stores value, source card, effect id and duration (battle / turn / permanent), so a specific effect can be removed without touching others. GrantedAbility lets effects add abilities that are not printed on the card; the engine merges printed and granted abilities. Boost and trigger bonuses now use modifiers. Three tests.
MpakobecEx