Implement the following plan:

Plan: Port XMage to Rust for RL AI Training

Context

XMage is a Java MTG engine that is not thread-safe and doesn't efficiently use CPU at scale. The goal is to port the core game engine, AI player framework, and cards from 4 sets to Rust, with Python bindings via PyO3 for use as an OpenAI Gymnasium RL environment. Only standard 1v1 (two-player duel) is needed.

Card sets to port:

• FDN (Foundations, ~730 entries) — curated subset (~150 cards) for core mechanics coverage: counterspells, removal, vanilla creatures, equipment, auras, tokens, basic lands
• TLA (Avatar: The Last Airbender, ~392 cards) — full set
• TDM (Tarkir: Dragonstorm, ~432 cards) — full set
• ECL (Lorwyn Eclipsed, ~227 cards) — full set

Project Structure

Cargo workspace at /mnt/dest-btrfs/home/jc/src/mage/mtg-rl/:

mtg-rl/
  Cargo.toml                    # workspace root
  crates/
    mtg-engine/                 # Core rules engine
    mtg-cards/                  # Card implementations (FDN, TLA, TDM, ECL)
    mtg-ai/                     # AI players + RL interface
    mtg-python/                 # PyO3 bindings (cdylib)
    mtg-tests/                  # Integration test framework + ported JUnit tests

Team Structure (3 teammates)

Teammate 1: engine — Core Game Engine

Teammate 2: ai — AI Players + PyO3/Gymnasium

Teammate 3: cards — Card Implementations for FDN, TLA, TDM, ECL

---

Phase 1: Foundation (all teams start in parallel)

Engine teammate

1. Set up Cargo workspace with all 5 crates
2. constants.rs — All enums (Zone, PhaseStep, CardType, SubType, Layer, Duration, etc.) from Mage/src/main/java/mage/constants/
3. types.rs — ObjectId, PlayerId (Uuid-based typed wrappers)
4. mana.rs — Mana struct + arithmetic (port Mage/src/main/java/mage/Mana.java)
5. counters.rs — Counter types
6. card.rs — CardData struct (composition-based, replaces CardImpl inheritance)
7. permanent.rs — Permanent struct (embeds CardData + battlefield state)
8. player/player.rs — Player struct with life/hand/library/graveyard
9. player/mana_pool.rs — ManaPool
10. battlefield.rs, stack.rs — Zone containers
11. zones.rs — Zone management + zone change logic (port ZonesHandler.java)
12. state.rs — GameState struct aggregating all zones/effects/triggers
13. turn.rs — Turn/Phase/Step state machine
14. game.rs — Game struct shell with new_two_player(), turn loop skeleton

Key design decisions:

• Use im crate for persistent HashMap/Vector (cheap clone for AI search)
• Use bitflags for keyword abilities (O(1) checks vs Java's hash lookup)
• All types Send + Sync — no Rc, RefCell, or raw pointers
• UUID-based object references (direct translation from Java)

AI teammate

1. Define PlayerDecisionMaker trait — the ~15 decision methods from Player.java:
   • priority(), choose_target(), choose_use(), select_attackers(), select_blockers(), choose_mode(), assign_damage(), choose_mulligan(), etc.
2. Define PlayerAction enum (Pass, CastSpell, ActivateAbility, PlayLand)
3. random_player.rs — Random legal-action player (testing baseline)
4. evaluator.rs — Port GameStateEvaluator2 scoring (life + permanents + hand)
5. Design observation encoding (observation.rs) and action space (action.rs)

Critical dependency: AI teammate delivers PlayerDecisionMaker trait by end of Phase 1. Engine integrates it into the game loop.

Cards teammate

1. registry.rs — CardRegistry with type CardFactory = fn(ObjectId, PlayerId) -> CardData
2. Set registration files: sets/fdn.rs, sets/tla.rs, sets/tdm.rs, sets/ecl.rs
3. All basic lands for each set
4. FDN curated subset first (~150 cards covering core mechanics):
   • Counterspells (Cancel, etc.)
   • Basic removal (Murder, Doom Blade type)
   • Vanilla/keyword creatures across all colors
   • Equipment and auras
   • Token creators
   • Card draw spells
   • Combat tricks
5. All Tier 1 cards from TLA/TDM/ECL — vanilla/keyword-only creatures (~30%)

Critical dependency: Cards teammate needs CardData struct from Engine by end of week 1.

---

Phase 2: Core Systems

Engine teammate

1. events.rs — GameEvent enum (600+ types), fire_event, replace_event dispatch
2. priority.rs — Priority loop (port GameImpl.playPriority)
3. abilities/ability.rs — Ability trait + common implementations
4. abilities/activated.rs, triggered.rs, spell.rs, static_ability.rs, mana_ability.rs
5. effects/continuous.rs — 7-layer effects system (port ContinuousEffects.java):
   • Layer 1: Copy → 2: Control → 3: Text → 4: Type → 5: Color → 6: Ability → 7: P/T (with sublayers 7a-7e)
6. effects/replacement.rs, one_shot.rs, prevention.rs, restriction.rs
7. combat.rs — Full combat system (port Combat.java — declare attackers/blockers, damage assignment)
8. watchers/ — Watcher trait + common watchers
9. filters/ — Filter/Predicate composable system (port StaticFilters.java)
10. targets/ — Target system (TargetCard, TargetPermanent, TargetPlayer)

AI teammate

1. heuristic_player.rs — Port ComputerPlayer.java (1,350 lines) — heuristic-based decisions
2. Start minimax_player.rs — Port ComputerPlayer6.java (1,251 lines) — minimax with alpha-beta + parallel search via rayon
3. Start gym.rs — Gymnasium env logic (step/reset/observation/action_mask)
4. mtg-python/src/lib.rs — PyO3 module skeleton with #[pyclass] MtgEnv

Cards teammate

1. Set-specific keyword mechanics:
   • keywords/waterbend.rs — TLA mechanic
   • keywords/airbend.rs — TLA mechanic
   • keywords/mobilize.rs — TDM mechanic
2. Port common building-block abilities to mtg-engine:
   • Triggers: EntersBattlefieldTriggeredAbility, DiesTriggeredAbility, AttacksTriggeredAbility, DealsCombatDamageToAPlayerTriggeredAbility, BeginningOfEndStepTriggeredAbility, SpellCastControllerTriggeredAbility
   • Effects: DestroyTargetEffect, ExileTargetEffect, DamageTargetEffect, DrawCardSourceControllerEffect, GainLifeEffect, BoostTargetEffect, BoostControlledEffect, CreateTokenEffect, CounterTargetEffect, ScryEffect, ExileUntilSourceLeavesEffect
   • Costs: TapSourceCost, SacrificeSourceCost, DiscardCost, PayLifeCost
3. All Tier 2 cards (~35%) — standard ability compositions across all 4 sets
4. Begin Tier 3 cards (~20%) — modal spells, lords, conditional effects

---

Phase 3: Integration & Complex Cards

Engine teammate

1. Complete game loop: full game playable with simple cards end-to-end
2. State-based actions (SBA) checking
3. Stack resolution edge cases (fizzle, counter, copy on stack)
4. Last-known information (LKI) system
5. Transform/double-faced card support
6. Aura/equipment attachment system
7. Performance: profiling, im:: tuning, verify Send + Sync everywhere
8. Concurrency validation: run parallel games via rayon, establish baseline throughput

AI teammate

1. Complete minimax player with parallel branch search
2. Complete PyO3 bindings + Python Gymnasium wrapper (pip install via maturin)
3. Reward shaping: win/loss (+1/-1), intermediate reward from life differential
4. Action space: two-phase approach (action type selection, then parameterization) to avoid combinatorial explosion
5. Observation space: fixed-size tensors (life, mana, permanents, hand, stack, phase, action mask)

Cards teammate

1. All Tier 3 cards — moderate complexity (modal, lords, multi-ability)
2. All Tier 4 cards (~15%) — planeswalkers, DFCs, sagas, custom effects
3. Card-specific unit tests for every complex card

---

Phase 4: Testing & Polish

Test strategy: Port core + cherry-pick + gap-fill

1. Port ALL existing core engine tests from Mage.Tests/:

• Combat tests (12 files) — Mage.Tests/.../test/combat/
• Game tests (5 files) — Mage.Tests/.../test/game/
• State-based action tests (1 file)
• Turn modification tests (2 files)
• LKI tests (1 file)

2. Port card-specific tests for our 4 sets:

• TDM: 7 existing test files
• FDN: 1 existing test file
• TLA, ECL: 0 existing tests (write new ones)

3. Cherry-pick card tests from OTHER sets that exercise critical mechanics missing from our sets:

• Counterspell interactions (stack mechanics)
• Replacement effect ordering
• Triggered ability ordering (APNAP)
• Copy/clone effects
• X spells
• Protection/hexproof/ward
• Sacrifice-as-cost vs sacrifice-as-effect
• "Dies" triggers vs "leaves the battlefield"

4. Write new Rust tests for remaining gaps:

• 7-layer continuous effects system (each layer individually + interactions)
• Mana payment system (generic, colored, conditional, hybrid)
• Stack resolution (priority passing, fizzle, counter)
• Zone transition edge cases
• State-based actions (comprehensive)

5. Fuzz + performance testing:

• Random games with crash detection
• Establish games/second baseline and profile bottlenecks (optimize iteratively, no fixed target)
• Verify the Gymnasium env runs end-to-end (reset → step → observe → repeat)
• RL agent training (PPO etc.) deferred to a future phase

Test framework mirrors CardTestPlayerBase API:

---

Key Design Decisions

Critical Source Files (Java → Rust reference)

• Mage/src/main/java/mage/game/GameImpl.java (4,270 lines) → mtg-engine/src/game.rs
• Mage/src/main/java/mage/game/GameState.java (1,758 lines) → mtg-engine/src/state.rs
• Mage/src/main/java/mage/abilities/effects/ContinuousEffects.java (1,427 lines) → mtg-engine/src/effects/continuous.rs
• Mage/src/main/java/mage/game/combat/Combat.java (1,956 lines) → mtg-engine/src/combat.rs
• Mage/src/main/java/mage/game/permanent/PermanentImpl.java (2,202 lines) → mtg-engine/src/permanent.rs
• Mage/src/main/java/mage/abilities/AbilityImpl.java (1,966 lines) → mtg-engine/src/abilities/ability.rs
• Mage/src/main/java/mage/players/Player.java (760 lines) → PlayerDecisionMaker trait
• Mage.Player.AI.MA/.../ComputerPlayer6.java (1,251 lines) → mtg-ai/src/minimax_player.rs
• Mage.Player.AI/.../ComputerPlayer.java (1,350 lines) → mtg-ai/src/heuristic_player.rs
• Mage.Sets/src/mage/sets/Foundations.java — FDN set definition (curated subset source)
• Mage.Sets/src/mage/sets/AvatarTheLastAirbender.java — TLA set definition
• Mage.Sets/src/mage/sets/TarkirDragonstorm.java — TDM set definition
• Mage.Sets/src/mage/sets/LorwynEclipsed.java — ECL set definition

If you need specific details from before exiting plan mode (like exact code snippets, error messages, or content you generated), read the full transcript at: /mnt/dest-btrfs/home/jc/.claude/projects/-mnt-dest-btrfs-home-jc-src-mage/60ce8554-7ed5-4f1a-b3ee-e636dd4f7ae0.jsonl

If this plan can be broken down into multiple independent tasks, consider using the TeamCreate tool to create a team and parallelize the work.

<teammate-message teammate_id="engine" color="blue" summary="Task #5 done: player, mana pool, zones, state implemented"> Task #5 complete: player.rs, mana_pool.rs, zones.rs, and state.rs are all implemented with 51 total passing tests in mtg-engine.

Key types now available:

• ManaPool - mana pool with colored/generic spending, atomic try_pay, restrictions
• Library, Hand, Graveyard, Exile, Battlefield, Stack, CommandZone - all zone containers
• CardStore - central card data storage by ObjectId
• Player - full player state (life, counters, zones, mana pool, land plays, hand size, game flags)
• GameState - complete game state with players, zones, turn tracking, SBA checking
• StateBasedActions - SBA detection (life loss, poison, lethal damage, zero toughness, indestructible)

Task #6 (turn.rs and game.rs) is now unblocked. Starting that next.
</teammate-message>

<teammate-message teammate_id="ai" color="green" summary="Task #21 complete, all 52 mtg-ai tests pass"> Task #21 (minimax AI player) is complete. All 52 mtg-ai tests pass.

The fix for the failing minimax_ab_alpha_beta_pruning test was a bug in the terminal node check logic in minimax_ab(). The root node's initial score was set to LOSE_SCORE (as a default for maximizing nodes), and the terminal check if node.score == WIN_SCORE || node.score == LOSE_SCORE was incorrectly triggering on it before the search could explore children. The fix removes the separate terminal check and folds it into the leaf check — a node is only a leaf/terminal if depth == 0 or node.children.is_empty(). Non-leaf nodes with children always proceed to the search loop.

I also fixed a cross-crate compilation issue: tdm.rs referenced evolving_wilds from fdn.rs which was private. Made it pub and updated the reference to super::fdn::evolving_wilds.

All my assigned tasks are now complete:

• #7: PlayerDecisionMaker trait
• #8: RandomPlayer + evaluator
• #9: Observation/action space
• #20: Heuristic player
• #21: Minimax player
• #22: PyO3 + Gymnasium

Note: there's a pre-existing extra_turns_lifo test failure in mtg-engine that belongs to the engine teammate.

Files modified:

• /mnt/dest-btrfs/home/jc/src/mage/mtg-rl/mtg-ai/src/minimax_player.rs (line 249-254: fixed leaf/terminal check)
• /mnt/dest-btrfs/home/jc/src/mage/mtg-rl/mtg-cards/src/sets/fdn.rs (line 125: made evolving_wilds pub)
• /mnt/dest-btrfs/home/jc/src/mage/mtg-rl/mtg-cards/src/sets/tdm.rs (line 18: use super::fdn::evolving_wilds)

</teammate-message>

<teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:04.868Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green" summary="All 6 assigned tasks already complete, available for new work"> Hi — I believe this message may be from earlier in our session. All my assigned tasks are already complete:

• #7: PlayerDecisionMaker trait (completed)
• #8: RandomPlayer + evaluator (completed)
• #9: Observation/action space (completed)
• #20: Heuristic player (completed)
• #21: Minimax player (completed, just fixed the last failing test)
• #22: PyO3 + Gymnasium (completed)

All 52 mtg-ai tests pass, plus 2 mtg-cards tests. The only failure in the workspace is extra_turns_lifo in mtg-engine which belongs to the engine teammate.

I'm available for any new work. The remaining tasks on the board are blocked on engine (#6 -> #13 -> #14 chain) or cards (#10 -> #11, #12). If there's anything else I can help with — like assisting with the game event system (#13) or helping unblock the engine/cards work — just let me know.
</teammate-message>

<teammate-message teammate_id="engine" color="blue" summary="Task #6 done: turn manager and game loop implemented"> Task #6 complete: turn.rs and game.rs are implemented with 64 total passing tests in mtg-engine.

Key types now available:

• TurnManager - full MTG turn state machine (13 steps, phase mapping, extra turns LIFO, end-turn-early, first strike step toggling)
• PriorityTracker - tracks consecutive passes for stack resolution
• Game - top-level game runner with:
  • new_two_player() constructor taking deck configs and decision makers
  • run() method that plays a full game to completion
  • Turn-based actions (untap, draw, cleanup/discard, damage removal)
  • Priority loop (pass/play land/cast spell/resolve stack)
  • State-based action processing (life, poison, lethal damage, 0 toughness, indestructible)
  • Legal action computation (lands, sorcery/instant timing, mana payment check)
  • Stack resolution (permanent spells enter battlefield, non-permanents to graveyard)

The game_runs_to_completion test verifies that two AlwaysPassPlayers play a game that ends by decking.

Task #13 (events.rs) is now unblocked. Starting that next.
</teammate-message>

<teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:21.087Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:25.601Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:29.634Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:33.081Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:36.877Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:39.807Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:42.820Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:46.393Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:52.662Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:46:58.242Z","idleReason":"available"} </teammate-message> <teammate-message teammate_id="engine" color="blue" summary="Task #13 done: events.rs with 100 event types implemented"> Task #13 complete: events.rs implemented with 72 total passing tests in mtg-engine.

Key types now available:

• EventType enum — ~100 event types covering turn structure, zone changes, spells/abilities, damage, life, combat, permanents, counters, tokens, lands, control, targeting, and more
• GameEvent struct with builder pattern: target_id, source_id, player_id, amount, flag, data, zone, prevented, applied_effects
• Convenience constructors: damage_player, damage_permanent, gain_life, lose_life, draw_card, discard_card, zone_change, spell_cast, enters_battlefield, dies, destroy_permanent, add_counters, tap, declare_attacker, declare_blocker
• EventLog — event accumulator for triggered ability checking

Task #14 (priority system and ability/effect framework) is now unblocked. Starting that next.
</teammate-message>

<teammate-message teammate_id="ai" color="green"> {"type":"idle_notification","from":"ai","timestamp":"2026-02-13T17:48:24.791Z","idleReason":"available"} </teammate-message>

<teammate-message teammate_id="engine" color="blue" summary="Task #14 done: ability/effect framework with 40+ effect types"> Task #14 complete: abilities.rs and effects.rs implemented with 86 total passing tests in mtg-engine.

Key types now available:

• abilities.rs:

  • Cost enum (Mana, TapSelf, PayLife, SacrificeSelf, Discard, etc.)
  • Effect enum (~40 effect variants: DealDamage, GainLife, Destroy, DrawCards, AddCounters, CreateToken, BoostUntilEndOfTurn, GainKeyword, CounterSpell, etc.)
  • TargetSpec enum (None, Creature, CreatureOrPlayer, Permanent, Spell, etc.)
  • Ability struct with constructors: activated(), triggered(), static_ability(), mana_ability(), spell()
  • StaticEffect enum (Boost, GrantKeyword, CantAttack, CostReduction, etc.)
  • AbilityStore — indexed by AbilityId and source ObjectId, with triggered_by() and mana_abilities_for()

• effects.rs:

  • ContinuousEffect struct with 7-layer system (Layer/SubLayer), timestamps, durations
  • EffectModification enum (CopyObject, ChangeControl, AddType, AddKeyword, ModifyPowerToughness, etc.)
  • ContinuousEffects manager with layer-based queries and timestamp ordering
  • ReplacementEffect struct (Prevent, ExileInstead, ModifyAmount, EnterTapped, etc.)
  • ReplacementEffects manager

Cards teammate: you can now define card abilities using these types. Example:

Tasks #15, #16, #17 are now unblocked.
</teammate-message>

<teammate-message teammate_id="engine" color="blue" summary="Task #16 complete: filters, targets, watchers"> Task #16 (filters.rs, targets.rs, watchers.rs) is complete. All 128 mtg-engine tests pass.

New modules:

• filters.rs: Composable predicate-based filter system (Predicate enum with And/Or/Not combinators, Filter wrapper with matches_permanent/matches_card, pre-built filters like any_creature, creature_you_control, nonland_permanent, etc.)
• targets.rs: Target definitions (TargetDefinition with zone, filter, min/max targets, is_targeted) and selected targets tracking (SelectedTargets with object/player target entries, legality marking)
• watchers.rs: WatcherManager with built-in per-turn PlayerTurnStats (spells cast, cards drawn, life gained/lost, creatures died, entered/left battlefield, attackers) and GameTurnStats, plus CustomWatcher for card-specific tracking with scope filtering

Task #17 (common building-block abilities and effects) is now unblocked. Starting that next.
</teammate-message>

<teammate-message teammate_id="engine" color="blue" summary="Task #17 complete: building-block abilities/effects"> Task #17 (common building-block abilities and effects) is complete. All 141 mtg-engine tests pass.

Added to abilities.rs:

• Triggered ability builders: enters_battlefield_triggered, dies_triggered, attacks_triggered, combat_damage_to_player_triggered, beginning_of_upkeep_triggered, beginning_of_end_step_triggered, spell_cast_triggered, other_creature_etb_triggered, any_creature_dies_triggered
• Effect builders: deal_damage, draw_cards, gain_life, lose_life, boost_until_eot, create_token, counter_spell, scry, mill, discard_cards, bounce, reanimate, add_p1p1_counters, tap_target, untap_target, destroy_all, damage_opponents, search_library, gain_control, gain_protection, indestructible, hexproof, etc.
• Static effect builders: boost_controlled, grant_keyword_controlled, cant_block, cant_attack, cost_reduction
• Cost builders: pay_mana, tap_self, sacrifice_self, sacrifice_other, pay_life, discard, exile_from_hand, exile_from_graveyard, remove_counters

Tasks #18, #19, and #23 are now unblocked. Starting task #23 (complete game loop) next.
</teammate-message>

<teammate-message teammate_id="cards" color="yellow" summary="Completed FDN 154 cards, all tests pass"> Completed tasks #11 and #12:

Task #11 — FDN curated subset (~150 cards): Done. FDN now has 154 cards total (149 unique + 5 basic lands). Added 79 Tier 2 cards including:

• 14 vanilla/keyword creatures (Savannah Lions, Gigantosaurus, Shivan Dragon, Juggernaut, etc.)
• 32 creatures with abilities (Guttersnipe, Reclamation Sage, Inspiring Overseer, Brineborn Cutthroat, etc.)
• 23 instants (Giant Growth, Unsummon, Cancel, Negate, Opt, Snakeskin Veil, etc.)
• 9 sorceries (Day of Judgment, Duress, Dragon Fodder, Chart a Course, etc.)
• 1 enchantment (Pacifism)

Task #12 — Tier 1 TLA/TDM/ECL: Already completed last session. All Tier 1 cards from tier files implemented.

All 5 cargo tests pass. Current set card counts:

• FDN: 154 cards
• TLA: 52 cards (someone added 32 more since last session)
• TDM: 65 cards
• ECL: 40 cards

Updated test assertions to use >= thresholds so they stay robust as teammates add cards.

Ready for next task — I can work on Task #18 (set-specific keywords) or #19 (Tier 2 for TLA/TDM/ECL) if their blockers (#17) are resolved.
</teammate-message>