AGENTS.md

@@ -1,5 +1,6 @@
 # AGENTS.md
-Godot 4.6 idle-game prototype; code is GDScript + `.tscn` scenes + JSON data at repo root.
+Godot 4.6 idle-game; code is GDScript + `.tscn` scenes.
+
 ## Build, Lint, And Test Commands
 Use `GODOT_BIN` for your local editor binary (e.g. `godot`, `godot4`, or full path).
 Run project: `"$GODOT_BIN" --path .`
@@ -7,12 +8,14 @@ Headless smoke/lint parse: `"$GODOT_BIN" --headless --path . --quit`
 Script syntax check (single script): `"$GODOT_BIN" --headless --check-only --script res://big_number.gd`
 Tests: no test framework is currently committed (`tests/` and `addons/gut` are absent).
 Single-test command: N/A right now; if GUT is added, use `"$GODOT_BIN" --headless --path . -s res://addons/gut/gut_cmdln.gd -gtest=res://tests/<file>.gd`.
+
 ## Architecture And Structure
 `project.godot` defines autoload singletons: `GameState` (runtime currency state + save/load) and `CurrencyGeneratorDatabase` (loads `generator_data.json`).
 `big_number.gd` (`class_name BigNumber`) is the internal numeric API for huge-value math, comparisons, formatting, and serialization.
 `big_number_museum.tscn` + `big_number_museum.gd` is the current main playable scene/prototype UI.
 `currency_generator.gd`, `currency_label.gd`, and `big_number_progress_bar.gd` are UI/gameplay adapters that react to `GameState` signals.
 Persistence is local JSON only: `user://idle_save.json`; there is no external DB/server/backend.
+
 ## Code Style And Conventions
 Prefer typed GDScript (`var x: Type`, `func f() -> void`) and keep shared models/components as `class_name` scripts.
 Naming: `snake_case` for vars/functions/signals, `PascalCase` for classes, `UPPER_SNAKE_CASE` for constants.
@@ -20,3 +23,4 @@ Follow existing Godot style: tabs/consistent indentation, early returns, and sho
 When reading files/JSON, always guard `FileAccess.open(...)` and validate parsed types before indexing.
 Use signals (already in `GameState`) for UI updates instead of polling or cross-node direct mutation.
 No Cursor/Claude/Windsurf/Cline/Goose/Copilot rule files were found in this repository, so this file is the canonical agent guidance.
+Avoid trivial one-line wrapper/helper functions that only forward or repack data. Inline the logic at the real call site unless the wrapper adds meaningful abstraction or is reused enough to justify it.

README.md

@@ -37,7 +37,6 @@ A modular idle/incremental game prototype featuring a decoupled buff system, mul
 | `LevelGameState` | `core/level_game_state.gd` | Central state management, save/load |
 | `CurrencyCatalogue` | `core/currency_catalogue.gd` | Currency catalog resource |
 | `PrestigeManager` | `core/prestige/prestige_manager.gd` | Prestige system |
-| `ResearchXPTracker` | `core/research/research_xp_tracker.gd` | Research XP accumulation |
 
 ### Data Directory Structure
 

core/generator/currency_generator.gd

@@ -39,9 +39,6 @@ const HUGE_COST_EXPONENT: int = 1000000
 ## Reference to generator UI
 @export var info_generator_container: GeneratorPanel
 
-## Reference to research tracker
-var research_tracker: Node = null
-
 ## True while the pointer is inside the generator Area2D.
 var _mouse_entered: bool = false
 ## Time left until next click/hover grant is allowed.
@@ -108,8 +105,7 @@ func _ready() -> void:
 		game_state.currency_changed.connect(_on_currency_changed)
 		game_state.generator_state_changed.connect(_on_generated_state_changed)
 		game_state.goal_completed.connect(_on_goal_completed)
-		# Don't cache research_tracker here - it may not be initialized yet
+		# Research XP is awarded via game_state.add_research_xp() - buff calculation handled statically
-		# Access it lazily when needed instead
 	
 	_ensure_registered()
 
@@ -155,11 +151,7 @@ func _grant_cycle_income(cycle_count: int) -> void:
 		var amount_float: float = produced.mantissa * pow(10.0, float(produced.exponent))
 		var research_xp_amount: BigNumber = BigNumber.from_float(data.research_data.xp_per_currency_produced * amount_float)
 		if game_state != null and research_xp_amount.mantissa > 0.0:
-			var tracker: ResearchXPTracker = game_state.research_tracker as ResearchXPTracker
+			game_state.add_research_xp(data.research_data.id, research_xp_amount)
-			if tracker:
-				tracker.add_xp_with_buffs(data.research_data.id, research_xp_amount)
-			else:
-				game_state.add_research_xp(data.research_data.id, research_xp_amount)
 
 ## Convenience helper for the next single-unit purchase cost.
 func get_next_cost() -> BigNumber:
@@ -444,11 +436,7 @@ func _try_grant_click_currency() -> void:
 		var amount_float: float = click_value.mantissa * pow(10.0, float(click_value.exponent))
 		var research_xp_amount: BigNumber = BigNumber.from_float(data.research_data.xp_per_currency_produced * amount_float)
 		if game_state != null and research_xp_amount.mantissa > 0.0:
-			var tracker: ResearchXPTracker = game_state.research_tracker as ResearchXPTracker
+			game_state.add_research_xp(data.research_data.id, research_xp_amount)
-			if tracker:
-				tracker.add_xp_with_buffs(data.research_data.id, research_xp_amount)
-			else:
-				game_state.add_research_xp(data.research_data.id, research_xp_amount)
 	
 
 ## Resolves click reward from data.

core/generator/research_buff_calculator.gd

@@ -0,0 +1,22 @@
+## Static utility class for research XP buff calculations
+class_name ResearchBuffCalculator
+
+static func apply_buffs(game_state: LevelGameState, research_id: StringName, base_xp: BigNumber) -> BigNumber:
+	if game_state == null:
+		return base_xp
+	
+	var multiplier: float = _calculate_buff_multiplier(game_state, research_id)
+	var multiplier_bn: BigNumber = BigNumber.from_float(multiplier)
+	return base_xp.multiply(multiplier_bn)
+
+static func _calculate_buff_multiplier(game_state: LevelGameState, research_id: StringName) -> float:
+	var research: ResearchData = game_state.research_catalogue.get_research_by_id(research_id)
+	if research == null or research.associated_buff_id.is_empty():
+		return 1.0
+	
+	var buff: GeneratorBuffData = game_state.get_buff(research.associated_buff_id)
+	if buff == null or not game_state.is_buff_active(buff.id):
+		return 1.0
+	
+	var level: int = game_state.get_buff_level(buff.id)
+	return buff.get_effect_multiplier(level)

core/generator/research_buff_calculator.gd.uid

@@ -0,0 +1 @@
+uid://bhrcgp2dna0mb

core/level_game_state.gd

@@ -46,7 +46,6 @@ var _goal_completed: Dictionary = {}
 
 var research_xp: Dictionary = {}
 var research_levels: Dictionary = {}
-var research_tracker: Node = null
 
 var last_save_time: int = 0
 
@@ -80,6 +79,8 @@ var prestige_manager: PrestigeManager
 
 func _ready() -> void:
 	prestige_manager = find_child("PrestigeManager")
+	assert(prestige_manager != null)
+	
 	_initialize_currency_maps()
 	_initialize_catalogues()
 	_load_catalogue_goals()
@@ -482,9 +483,11 @@ func get_research_multiplier(research_id: StringName) -> float:
 	return research.get_multiplier_for_level(level)
 
 func add_research_xp(research_id: StringName, xp: BigNumber) -> void:
+	var actual_xp: BigNumber = ResearchBuffCalculator.apply_buffs(self, research_id, xp)
+	
 	var old_level: int = get_research_level(research_id)
 	var current_xp: BigNumber = get_research_xp(research_id)
-	research_xp[research_id] = current_xp.add(xp)
+	research_xp[research_id] = current_xp.add(actual_xp)
 	
 	var research: ResearchData = _get_research_data(research_id)
 	if research != null:
@@ -496,20 +499,6 @@ func add_research_xp(research_id: StringName, xp: BigNumber) -> void:
 	
 	research_xp_changed.emit(research_id, research_xp[research_id])
 
-func get_research_xp_multiplier(research_id: StringName) -> float:
-	var multiplier: float = 1.0
-	var research: ResearchData = _get_research_data(research_id)
-	if research == null:
-		return 1.0
-	
-	if not research.associated_buff_id.is_empty():
-		var buff: GeneratorBuffData = get_buff(research.associated_buff_id)
-		if buff != null and is_buff_active(buff.id):
-			var level: int = get_buff_level(buff.id)
-			multiplier *= buff.get_effect_multiplier(level)
-	
-	return multiplier
-
 func _get_research_data(research_id: StringName) -> ResearchData:
 	if research_catalogue == null:
 		return null

core/research/README.md

@@ -10,30 +10,26 @@ specific generators and can be enhanced with purchasable buffs that increase XP
 
 | File | Purpose |
 |------|---------|
-| `research_xp_tracker.gd` | Accumulates XP from production and handles auto-leveling (Node) |
 | `research_catalogue.gd` | Resource holding all research configurations |
 | `research_panel.gd` | UI panel showing all research tracks |
 | `research_row.gd` | UI row component for individual research display |
+| `../generator/research_buff_calculator.gd` | Static utility for buff multiplier calculations |
 
 ## Architecture
 
 ```
 LevelGameState (Node2D)
-├── ResearchXPTracker (child node)
-│   ├── Receives production_tick signals
-│   ├── Applies buff multipliers
-│   ├── Awards XP to research tracks
-│   └── Auto-levels when thresholds reached
 ├── research_xp: Dictionary
 ├── research_levels: Dictionary
-└── research_catalogue: ResearchCatalogue
+├── research_catalogue: ResearchCatalogue
-	└── ResearchPanel (UI, always visible)
+│   └── ResearchPanel (UI, always visible)
-		├── ResearchRow (for each research track)
+│       ├── ResearchRow (for each research track)
-		│   ├── Name & icon
+│       │   ├── Name & icon
-		│   ├── Level display
+│       │   ├── Level display
-		│   ├── Progress bar (percentage)
+│       │   ├── Progress bar (percentage)
-		│   ├── Multiplier indicator
+│       │   ├── Multiplier indicator
-		│   └── Active buff display
+│       │   └── Active buff display
+└── (buff calculation delegated to ResearchBuffCalculator static methods)
 ```
 
 ## Data Flow
@@ -42,12 +38,13 @@ LevelGameState (Node2D)
 Generator Production (currency_per_cycle)
 	│
 	▼
-ResearchXPTracker
+LevelGameState.add_research_xp()
 	1. base_xp = currency_produced * xp_per_currency_produced
-	2. actual_xp = base_xp * buff_multiplier
+	2. buff_multiplier = ResearchBuffCalculator.apply_buffs(research, buffs)
-	3. research_xp += actual_xp
+	3. actual_xp = base_xp * buff_multiplier
-	4. Check level threshold → auto-level
+	4. research_xp += actual_xp
-	5. Emit research_level_up signal
+	5. Check level threshold → auto-level
+	6. Emit research_level_up signal
 	│
 	▼
 ResearchState {xp: 150.5, level: 3}
@@ -143,38 +140,61 @@ func get_all_research() -> Array[ResearchData]
 
 Referenced directly by `LevelGameState` via `@export var research_catalogue: ResearchCatalogue`.
 
-## ResearchXPTracker
+## ResearchBuffCalculator
 
-Child node of `LevelGameState` that accumulates XP from production and applies buff multipliers.
+Static utility class for calculating research XP buff multipliers.
 
-### Signals
+### Location
 
-```gdscript
+`res://core/generator/research_buff_calculator.gd`
-signal research_xp_changed(research_id: StringName, new_xp: float)
-signal research_level_up(research_id: StringName, old_level: int, new_level: int)
-```
 
 ### Key Methods
 
 ```gdscript
-func add_xp_with_buffs(research_id: StringName, base_xp: BigNumber) -> BigNumber:
+static func apply_buffs(research: ResearchData, game_state: LevelGameState) -> float:
-	"""Apply buff multipliers and award XP. Returns actual XP after buffs (BigNumber)."""
+	"""Calculate total buff multiplier for research XP gain. Returns multiplicative factor."""
-	var buff_multiplier: float = game_state.get_research_xp_multiplier(research_id)
+	var multiplier: float = 1.0
-	var multiplier_bn: BigNumber = BigNumber.from_float(buff_multiplier)
+	if research.associated_buff_id.is_empty():
-	var actual_xp: BigNumber = base_xp.multiply(multiplier_bn)
+		return multiplier
-	game_state.add_research_xp(research_id, actual_xp)
-	return actual_xp
 	
-func _on_generator_produced(generator_id: StringName, amount: BigNumber) -> void:
+	var buff: GeneratorBuffData = game_state.get_buff(research.associated_buff_id)
-	var research: ResearchData = _get_research_for_generator(generator_id)
+	if buff != null and game_state.is_buff_active(buff.id):
-	var amount_float: float = amount.mantissa * pow(10.0, float(amount.exponent))
+		var buff_level: int = game_state.get_buff_level(buff.id)
-	var base_xp: BigNumber = BigNumber.from_float(research.xp_per_currency_produced * amount_float)
+		multiplier *= ResearchBuffCalculator._calculate_buff_multiplier(buff, buff_level)
-	add_xp_with_buffs(research.id, base_xp)
+	
+	return multiplier
+
+static func _calculate_buff_multiplier(buff: GeneratorBuffData, level: int) -> float:
+	"""Calculate buff effect multiplier at given level."""
+	return buff.get_effect_multiplier(level)
 ```
 
-### Connection
+### Usage
 
-Connected to `LevelGameState` via `generator_produced` signal.
+Called from `LevelGameState.add_research_xp()`:
+
+```gdscript
+func add_research_xp(research_id: StringName, xp: BigNumber) -> void:
+	var research: ResearchData = research_catalogue.get_research_by_id(research_id)
+	if research == null:
+		return
+	
+	# Apply buff multipliers
+	var buff_multiplier: float = ResearchBuffCalculator.apply_buffs(research, self)
+	var multiplier_bn: BigNumber = BigNumber.from_float(buff_multiplier)
+	var actual_xp: BigNumber = xp.multiply(multiplier_bn)
+	
+	# Store XP and check for level-up
+	var old_level: int = get_research_level(research_id)
+	research_xp[research_id] = research_xp.get(research_id, BigNumber.new(0.0, 0)).add(actual_xp)
+	var new_level: int = research.get_level_for_xp(research_xp[research_id])
+	
+	if new_level > old_level:
+		research_levels[research_id] = new_level
+		research_level_up.emit(research_id, old_level, new_level)
+	
+	research_xp_changed.emit(research_id, research_xp[research_id])
+```
 
 ## LevelGameState Extensions
 
@@ -182,7 +202,7 @@ Connected to `LevelGameState` via `generator_produced` signal.
 ```gdscript
 var research_xp: Dictionary = {}        # {research_id: BigNumber}
 var research_levels: Dictionary = {}    # {research_id: level_int}
-var research_tracker: ResearchXPTracker
+# research_tracker removed - buff calculation moved to static utility
 ```
 
 ### Signals
@@ -208,21 +228,27 @@ func get_research_multiplier(research_id: StringName) -> float:
 	return research.get_multiplier_for_level(level)
 
 func add_research_xp(research_id: StringName, xp: BigNumber) -> void:
-	"""Add XP (BigNumber) and auto-level if threshold reached"""
+	"""Add XP (BigNumber) with buff multipliers applied, auto-level if threshold reached"""
+	var research: ResearchData = research_catalogue.get_research_by_id(research_id)
+	if research == null:
+		return
+	
+	var old_level: int = get_research_level(research_id)
 	var current_xp: BigNumber = get_research_xp(research_id)
-	research_xp[research_id] = current_xp.add(xp)
+	
-	new_level = research.get_level_for_xp(research_xp[research_id])
+	# Apply buff multipliers via static utility
+	var buff_multiplier: float = ResearchBuffCalculator.apply_buffs(research, self)
+	var multiplier_bn: BigNumber = BigNumber.from_float(buff_multiplier)
+	var actual_xp: BigNumber = xp.multiply(multiplier_bn)
+	
+	research_xp[research_id] = current_xp.add(actual_xp)
+	var new_level: int = research.get_level_for_xp(research_xp[research_id])
+	
 	if new_level > old_level:
 		research_levels[research_id] = new_level
 		research_level_up.emit(research_id, old_level, new_level)
 	
-func get_research_xp_multiplier(research_id: StringName) -> float:
+	research_xp_changed.emit(research_id, research_xp[research_id])
-	"""Returns multiplicative buff for research XP gain"""
-	var multiplier: float = 1.0
-	var buff: GeneratorBuffData = get_buff(research.associated_buff_id)
-	if is_buff_active(buff.id):
-		multiplier *= buff.get_effect_multiplier(get_buff_level(buff.id))
-	return multiplier
 ```
 
 ### Save/Load Integration
@@ -272,11 +298,11 @@ func _grant_cycle_income(cycle_count: int) -> void:
 	_add_currency(produced)
 	production_tick.emit(produced, cycle_count, owned)
 	
-	# Award research XP (BigNumber)
+	# Award research XP (BigNumber) - buff multipliers applied in LevelGameState
 	if data.research_data != null:
 		var amount_float: float = produced.mantissa * pow(10.0, float(produced.exponent))
 		var xp: BigNumber = BigNumber.from_float(data.research_data.xp_per_currency_produced * amount_float)
-		research_tracker.add_xp_with_buffs(data.research_data.id, xp)
+		game_state.add_research_xp(data.research_data.id, xp)
 ```
 
 ### Research Multiplier
@@ -425,7 +451,7 @@ actual_xp = base_xp * xp_multiplier
 | Decision | Value |
 |----------|-------|
 | ResearchCatalogue reference | Direct `@export var research_catalogue: ResearchCatalogue` in LevelGameState |
-| ResearchXPTracker location | Child of `LevelGameState` (receives signals via connection) |
+| Buff calculation | Static utility (`ResearchBuffCalculator`) - no dedicated tracker node |
 | Progress bar display | Percentage format (e.g., "75%") |
 | Buff display | Shows buff name and effect (e.g., "Mining Expert: +20% XP") |
 | Research unlock | Starts unlocked |
@@ -438,8 +464,8 @@ actual_xp = base_xp * xp_multiplier
 ## System Behavior
 
 1. **Generator produces currency** → `production_tick` signal emitted
-2. **ResearchXPTracker receives signal** → calculates base XP from production amount
+2. **CurrencyGenerator calls** → `game_state.add_research_xp()` with base XP
-3. **Buff multipliers applied** → checks for active RESEARCH_XP_MULTIPLIER buffs
+3. **LevelGameState applies buffs** → `ResearchBuffCalculator.apply_buffs()` calculates multiplier
 4. **XP awarded** → stored in `research_xp` dictionary
 5. **Level check** → if XP exceeds threshold, auto-level and emit `research_level_up`
 6. **Multiplier applied** → `get_research_multiplier()` returns updated production bonus
@@ -458,4 +484,5 @@ On prestige reset:
 - `core/level_game_state.gd` - Research state storage and management
 - `core/generator/currency_generator_data.gd` - Links to ResearchData
 - `core/generator/generator_buff_data.gd` - RESEARCH_XP_MULTIPLIER buff type
+- `core/generator/research_buff_calculator.gd` - Static buff calculation utility
 - `core/research/research_catalogue.gd` - Research configuration resource

core/research/TODO.md

@@ -18,16 +18,10 @@ A production-based research system where:
 ```
 ┌─────────────────────────────────────────────────────────────────┐
 │                         LevelGameState                           │
-│  ┌─────────────────────────────────────────────────────────┐   │
-│  │              ResearchXPTracker (child node)              │   │
-│  │  - Receives production_tick signals                      │   │
-│  │  - Applies buff multipliers                              │   │
-│  │  - Awards XP to research tracks                          │   │
-│  │  - Auto-levels when thresholds reached                   │   │
-│  └─────────────────────────────────────────────────────────┘   │
 │  - research_xp: Dictionary                                       │
 │  - research_levels: Dictionary                                   │
 │  - research_catalogue: ResearchCatalogue                         │
+│  - add_research_xp() applies buffs via ResearchBuffCalculator   │
 └─────────────────────────────────────────────────────────────────┘
 							  │
 		  ┌───────────────────┼───────────────────┐
@@ -39,6 +33,12 @@ A production-based research system where:
 │ - emits signal  │  │ - Multiplier    │  │   research      │
 └─────────────────┘  └─────────────────┘  │ - Progress bars │
 										  └─────────────────┘
+		  │
+		  ▼
+┌───────────────────────────────────────────────────────────────┐
+│              ResearchBuffCalculator (static utility)           │
+│  - apply_buffs() calculates XP multiplier from active buffs    │
+└───────────────────────────────────────────────────────────────┘
 ```
 
 ---
@@ -50,15 +50,22 @@ Generator Production (currency_per_cycle)
 		 │
 		 ▼
 ┌──────────────────────┐
-│ ResearchXPTracker    │
+│ CurrencyGen          │
-│ 1. base_xp = currency_produced * xp_per_currency_produced
+│ emits production_tick │
-│ 2. actual_xp = base_xp * buff_multiplier
-│ 3. research_xp += actual_xp
-│ 4. Check level threshold → auto-level
-│ 5. Emit research_level_up signal
 └──────────────────────┘
 		 │
 		 ▼
+┌─────────────────────────────────────────┐
+│ LevelGameState.add_research_xp()        │
+│ 1. base_xp = currency_produced * rate   │
+│ 2. buff_mult = ResearchBuffCalculator.apply_buffs()
+│ 3. actual_xp = base_xp * buff_mult      │
+│ 4. research_xp += actual_xp             │
+│ 5. Check level threshold → auto-level   │
+│ 6. Emit research_level_up signal        │
+└─────────────────────────────────────────┘
+		 │
+		 ▼
 ┌──────────────────────┐
 │ ResearchState        │
 │ {xp: 150.5, level: 3}│
@@ -188,53 +195,33 @@ func get_all_research() -> Array[ResearchData]:
 
 ---
 
-### 3. ResearchXPTracker (core/research/research_xp_tracker.gd)
+### 3. ResearchBuffCalculator (core/generator/research_buff_calculator.gd)
 
-**Purpose:** Child of LevelGameState; accumulates XP from production and applies buff multipliers
+**Purpose:** Static utility class for calculating research XP buff multipliers
 
-**Location:** `res://core/research/research_xp_tracker.gd`
+**Location:** `res://core/generator/research_buff_calculator.gd`
-
-**Signals:**
-```gdscript
-signal research_xp_changed(research_id: StringName, new_xp: float)
-signal research_level_up(research_id: StringName, old_level: int, new_level: int)
-```
 
 **Key Methods:**
 ```gdscript
-func add_xp_with_buffs(research_id: StringName, base_xp: float) -> float:
+static func apply_buffs(research: ResearchData, game_state: LevelGameState) -> float:
-	"""Apply buff multipliers and award XP. Returns actual XP after buffs."""
+	"""Calculate total buff multiplier for research XP gain. Returns multiplicative factor."""
-	if game_state == null:
+	var multiplier: float = 1.0
-		return 0.0
+	if research.associated_buff_id.is_empty():
+		return multiplier
 	
-	var actual_xp: float = base_xp
+	var buff: GeneratorBuffData = game_state.get_buff(research.associated_buff_id)
+	if buff != null and game_state.is_buff_active(buff.id):
+		var buff_level: int = game_state.get_buff_level(buff.id)
+		multiplier *= _calculate_buff_multiplier(buff, buff_level)
 	
-	# Apply research-specific buff multiplier
+	return multiplier
-	var buff_multiplier: float = game_state.get_research_xp_multiplier(research_id)
-	actual_xp *= buff_multiplier
 
-	# Award XP (handles auto-leveling internally)
+static func _calculate_buff_multiplier(buff: GeneratorBuffData, level: int) -> float:
-	game_state.add_research_xp(research_id, actual_xp)
+	"""Calculate buff effect multiplier at given level."""
-	
+	return buff.get_effect_multiplier(level)
-	return actual_xp
-
-func _on_generator_produced(generator_id: StringName, amount: BigNumber) -> void:
-	var research: ResearchData = _get_research_for_generator(generator_id)
-	if research == null:
-		return
-	
-	var amount_float: float = amount.to_float()
-	if amount_float <= 0.0:
-		return
-	
-	var base_xp: float = research.xp_per_currency_produced * amount_float
-	if base_xp <= 0.0:
-		return
-	
-	add_xp_with_buffs(research.id, base_xp)
 ```
 
-**Connection:** Connected to `LevelGameState` via `generator_produced` signal
+**Usage:** Called from `LevelGameState.add_research_xp()` to apply buffs before storing XP
 
 ---
 
@@ -242,14 +229,14 @@ func _on_generator_produced(generator_id: StringName, amount: BigNumber) -> void
 
 **New State Variables:**
 ```gdscript
-var research_xp: Dictionary = {}        # {research_id: xp_float}
+var research_xp: Dictionary = {}        # {research_id: BigNumber}
 var research_levels: Dictionary = {}    # {research_id: level_int}
-var research_tracker: ResearchXPTracker
+# research_tracker removed - buff calculation moved to static utility
 ```
 
 **New Signals:**
 ```gdscript
-signal research_xp_changed(research_id: StringName, new_xp: float)
+signal research_xp_changed(research_id: StringName, new_xp: BigNumber)
 signal research_level_up(research_id: StringName, old_level: int, new_level: int)
 ```
 
@@ -262,12 +249,12 @@ signal research_level_up(research_id: StringName, old_level: int, new_level: int
 ```gdscript
 func register_research(research_id: StringName) -> void:
 	if not research_xp.has(research_id):
-		research_xp[research_id] = 0.0
+		research_xp[research_id] = BigNumber.new(0.0, 0)
 	if not research_levels.has(research_id):
 		research_levels[research_id] = 0
 
-func get_research_xp(research_id: StringName) -> float:
+func get_research_xp(research_id: StringName) -> BigNumber:
-	return research_xp.get(research_id, 0.0)
+	return research_xp.get(research_id, BigNumber.new(0.0, 0))
 
 func get_research_level(research_id: StringName) -> int:
 	return research_levels.get(research_id, 0)
@@ -279,11 +266,22 @@ func get_research_multiplier(research_id: StringName) -> float:
 		return 1.0
 	return research.get_multiplier_for_level(level)
 
-func add_research_xp(research_id: StringName, xp: float) -> void:
+func add_research_xp(research_id: StringName, xp: BigNumber) -> void:
-	var old_level: int = get_research_level(research_id)
+	"""Add XP with buff multipliers applied, auto-level if threshold reached"""
-	research_xp[research_id] = research_xp.get(research_id, 0.0) + xp
+	var research: ResearchData = research_catalogue.get_research_by_id(research_id)
+	if research == null:
+		return
 	
-	var new_level: int = _get_research_data(research_id).get_level_for_xp(research_xp[research_id])
+	var old_level: int = get_research_level(research_id)
+	var current_xp: BigNumber = get_research_xp(research_id)
+	
+	# Apply buff multipliers via static utility
+	var buff_multiplier: float = ResearchBuffCalculator.apply_buffs(research, self)
+	var multiplier_bn: BigNumber = BigNumber.from_float(buff_multiplier)
+	var actual_xp: BigNumber = xp.multiply(multiplier_bn)
+	
+	research_xp[research_id] = current_xp.add(actual_xp)
+	var new_level: int = research.get_level_for_xp(research_xp[research_id])
 	
 	if new_level > old_level:
 		research_levels[research_id] = new_level
@@ -291,22 +289,6 @@ func add_research_xp(research_id: StringName, xp: float) -> void:
 	
 	research_xp_changed.emit(research_id, research_xp[research_id])
 
-func get_research_xp_multiplier(research_id: StringName) -> float:
-	"""Returns multiplicative buff for research XP gain"""
-	var multiplier: float = 1.0
-	var research: ResearchData = _get_research_data(research_id)
-	if research == null:
-		return 1.0
-	
-	# Find associated buff and apply its multiplier
-	if not research.associated_buff_id.is_empty():
-		var buff: GeneratorBuffData = get_buff(research.associated_buff_id)
-		if buff != null and is_buff_active(buff.id):
-			var level: int = get_buff_level(buff.id)
-			multiplier *= buff.get_effect_multiplier(level)
-	
-	return multiplier
-
 func _get_research_data(research_id: StringName) -> ResearchData:
 	if research_catalogue == null:
 		return null
@@ -338,11 +320,6 @@ research_levels.clear()
 
 **Initialization in _ready():**
 ```gdscript
-# After initializing other state, create research tracker
-research_tracker = ResearchXPTracker.new()
-add_child(research_tracker)
-research_tracker.game_state = self
-
 # Initialize research state from catalogue
 if research_catalogue:
 	for research in research_catalogue.get_all_research():
@@ -377,10 +354,10 @@ func _grant_cycle_income(cycle_count: int) -> void:
 	_add_currency(produced)
 	production_tick.emit(produced, cycle_count, owned)
 	
-	# NEW: Award research XP
+	# Award research XP - buff multipliers applied in LevelGameState
 	if data.research_data != null:
 		var xp: float = data.research_data.xp_per_currency_produced * produced.to_float()
-		research_tracker.add_xp_with_buffs(data.research_data.id, xp)
+		game_state.add_research_xp(data.research_data.id, BigNumber.from_float(xp))
 ```
 
 **New Method:**
@@ -399,13 +376,6 @@ func get_effective_auto_run_multiplier() -> float:
 	return run_multiplier * get_research_multiplier() * get_automatic_production_multiplier() * _get_prestige_multiplier()
 ```
 
-**In `_ready()`:**
-```gdscript
-# Get reference to research tracker
-if game_state:
-	research_tracker = game_state.research_tracker
-```
-
 ---
 
 ### 7. GeneratorBuffData Extensions (core/generator/generator_buff_data.gd)
@@ -549,11 +519,11 @@ func _on_research_level_up(research_id: StringName, _old_level: int, _new_level:
 |------|------|-------|----------|--------|
 | 1 | Create `ResearchData` resource class | `core/generator/research_data.gd` | High | ⬜ |
 | 2 | Create `ResearchCatalogue` resource class | `core/research/research_catalogue.gd` | High | ⬜ |
-| 3 | Create `ResearchXPTracker` node class | `core/research/research_xp_tracker.gd` | High | ⬜ |
+| 3 | Create `ResearchBuffCalculator` static utility | `core/generator/research_buff_calculator.gd` | High | ✅ Done |
-| 4 | Add research state to `LevelGameState` | `core/level_game_state.gd` | High | ⬜ |
+| 4 | Add research state to `LevelGameState` | `core/level_game_state.gd` | High | ✅ Done |
 | 5 | Add `RESEARCH_XP_MULTIPLIER` buff kind | `core/generator/generator_buff_data.gd` | High | ⬜ |
 | 6 | Add `research_data` export to `CurrencyGeneratorData` | `core/generator/currency_generator_data.gd` | High | ⬜ |
-| 7 | Connect production to research XP in `CurrencyGenerator` | `core/generator/currency_generator.gd` | High | ⬜ |
+| 7 | Connect production to research XP in `CurrencyGenerator` | `core/generator/currency_generator.gd` | High | ✅ Done |
 | 8 | Create `ResearchRow` scene & script | `core/research/research_row.tscn`, `.gd` | Medium | ⬜ |
 | 9 | Create `ResearchPanel` scene & script | `core/research/research_panel.tscn`, `.gd` | Medium | ⬜ |
 | 10 | Add save/load support for research state | `core/level_game_state.gd` | Medium | ⬜ |
@@ -569,7 +539,7 @@ func _on_research_level_up(research_id: StringName, _old_level: int, _new_level:
 |----------|-------|
 | ResearchCatalogue reference | Direct `@export var research_catalogue: ResearchCatalogue` in LevelGameState |
 | ResearchCatalogue location | `core/research/research_catalogue.gd` (resource, referenced directly) |
-| ResearchXPTracker location | Child of `LevelGameState` (receives signals via connection) |
+| Buff calculation | Static utility (`ResearchBuffCalculator`) - no dedicated tracker node |
 | Progress bar display | Percentage format (e.g., "75%") |
 | Buff display | Shows buff name and effect (e.g., "Mining Expert: +20% XP") |
 | Research unlock | Starts unlocked |
@@ -619,7 +589,8 @@ actual_xp = base_xp * xp_multiplier
 - **Associated buffs** should be created as `GeneratorBuffData` with `BuffKind.RESEARCH_XP_MULTIPLIER`
 - **Buff names** are configured in the `text` field of each `GeneratorBuffData`
 - **ResearchPanel** should be added as a child node in the main game scene (always visible)
-- **Save format version** should be incremented to 4 when adding research support
+- **Save format version** should be incremented to 5 when adding research support (BigNumber XP)
+- **ResearchXPTracker removed** - buff calculation moved to static `ResearchBuffCalculator` utility
 
 ---
 

core/research/research_xp_tracker.gd

@@ -1,72 +0,0 @@
-class_name ResearchXPTracker
-extends Node
-
-@export var game_state: LevelGameState
-
-signal research_xp_changed(research_id: StringName, new_xp: BigNumber)
-signal research_level_up(research_id: StringName, old_level: int, new_level: int)
-
-func add_xp_with_buffs(research_id: StringName, base_xp: BigNumber) -> BigNumber:
-	if game_state == null:
-		return BigNumber.new(0.0, 0)
-	
-	var buff_multiplier: float = game_state.get_research_xp_multiplier(research_id)
-	var multiplier_bn: BigNumber = BigNumber.from_float(buff_multiplier)
-	var actual_xp: BigNumber = base_xp.multiply(multiplier_bn)
-	
-	game_state.add_research_xp(research_id, actual_xp)
-	
-	return actual_xp
-
-func _on_generator_produced(generator_id: StringName, _amount: Variant) -> void:
-	var research: ResearchData = _get_research_for_generator(generator_id)
-	if research == null:
-		return
-	
-	var research_catalogue: ResearchCatalogue = game_state.research_catalogue
-	if research_catalogue == null:
-		return
-	
-	research = research_catalogue.get_research_by_generator_id(generator_id)
-	if research == null:
-		return
-	
-	if not _is_research_active(research.id):
-		return
-	
-	var amount_big: BigNumber = _amount
-	var amount_float: float = amount_big.mantissa * pow(10.0, float(amount_big.exponent))
-	if amount_float <= 0.0:
-		return
-	
-	var base_xp: BigNumber = BigNumber.from_float(research.xp_per_currency_produced * amount_float)
-	if base_xp.mantissa <= 0.0:
-		return
-	
-	add_xp_with_buffs(research.id, base_xp)
-
-func _get_research_for_generator(generator_id: StringName) -> ResearchData:
-	if game_state == null or game_state.research_catalogue == null:
-		return null
-	return game_state.research_catalogue.get_research_by_generator_id(generator_id)
-
-func _is_research_active(research_id: StringName) -> bool:
-	if game_state == null:
-		return false
-	
-	var research_panel: Node = game_state.find_child("ResearchPanel", true, false)
-	if research_panel == null:
-		return true
-	
-	if research_panel.has_method("is_research_active"):
-		return research_panel.is_research_active(research_id)
-	
-	return true
-
-func activate_research(research_id: StringName) -> void:
-	if game_state == null:
-		return
-	
-	var research_panel: Node = game_state.find_child("ResearchPanel", true, false)
-	if research_panel != null and research_panel.has_method("activate_research"):
-		research_panel.activate_research(research_id)

core/research/research_xp_tracker.gd.uid

@@ -1 +0,0 @@
-uid://bv3a4utlnn2fg

docs/gyms/tiny_sword/tiny_sword.tscn

@@ -10,7 +10,6 @@
 [ext_resource type="Script" uid="uid://srkiu4qe8s2m" path="res://core/prestige/prestige_manager.gd" id="5_x77df"]
 [ext_resource type="Resource" uid="uid://dwmfvmusfskk6" path="res://docs/gyms/tiny_sword/prestige/primary_prestige.tres" id="6_xnhlc"]
 [ext_resource type="PackedScene" uid="uid://btkxru2gdjsgc" path="res://currency_tile.tscn" id="7_0cs5o"]
-[ext_resource type="Script" uid="uid://bv3a4utlnn2fg" path="res://core/research/research_xp_tracker.gd" id="8_no27p"]
 [ext_resource type="Resource" uid="uid://w4u1hddplb4e" path="res://docs/gyms/tiny_sword/currencies/gold.tres" id="9_1363k"]
 [ext_resource type="PackedScene" uid="uid://djedqovgngrx5" path="res://docs/gyms/tiny_sword/buildings/farm/farm.tscn" id="10_1lv5i"]
 [ext_resource type="Resource" uid="uid://dfxk30o34qe2s" path="res://docs/gyms/tiny_sword/currencies/worker.tres" id="10_i1cck"]
@@ -37,10 +36,6 @@ script = ExtResource("5_x77df")
 config = ExtResource("6_xnhlc")
 game_state = NodePath("..")
 
-[node name="ResearchXpTracker" type="Node" parent="LevelGameState" unique_id=229654635 node_paths=PackedStringArray("game_state")]
-script = ExtResource("8_no27p")
-game_state = NodePath("..")
-
 [node name="World" type="Node2D" parent="LevelGameState" unique_id=2118297724]
 
 [node name="ForestProps" type="Node2D" parent="LevelGameState/World" unique_id=649424542]