diff --git a/packages/pokemon/src/__tests__/storage.test.ts b/packages/pokemon/src/__tests__/storage.test.ts
index 6df65a716..d5b8ec1e1 100644
--- a/packages/pokemon/src/__tests__/storage.test.ts
+++ b/packages/pokemon/src/__tests__/storage.test.ts
@@ -1,5 +1,67 @@
 import { describe, test, expect } from 'bun:test'
-import { getDefaultBuddyData } from '../core/storage'
+import {
+	getDefaultBuddyData,
+	addToParty, removeFromParty, swapPartySlots, setActivePartyMember,
+	depositToBox, withdrawFromBox, moveInBox, renameBox,
+	findCreatureLocation, releaseCreature, getTotalCreatureCount, getAllCreatureIds,
+	addItemToBag, removeItemFromBag, getItemCount,
+	updateDailyStats, incrementTurns,
+} from '../core/storage'
+import type { BuddyData } from '../types'
+
+function makeData(creatureCount = 1): BuddyData {
+	const creatures = Array.from({ length: creatureCount }, (_, i) => ({
+		id: `creature-${i}`,
+		speciesId: 'bulbasaur' as const,
+		gender: 'male' as const,
+		level: 5,
+		xp: 0,
+		totalXp: 100,
+		nature: 'hardy',
+		ev: { hp: 0, attack: 0, defense: 0, spAtk: 0, spDef: 0, speed: 0 },
+		iv: { hp: 15, attack: 15, defense: 15, spAtk: 15, spDef: 15, speed: 15 },
+		moves: [
+			{ id: 'tackle', pp: 35, maxPp: 35 },
+			{ id: '', pp: 0, maxPp: 0 },
+			{ id: '', pp: 0, maxPp: 0 },
+			{ id: '', pp: 0, maxPp: 0 },
+		] as [any, any, any, any],
+		ability: 'overgrow',
+		heldItem: null,
+		friendship: 70,
+		isShiny: false,
+		hatchedAt: Date.now(),
+		pokeball: 'pokeball',
+	}))
+
+	const party: (string | null)[] = [creatures[0]!.id, null, null, null, null, null]
+	if (creatureCount > 1) party[1] = creatures[1]!.id
+	if (creatureCount > 2) party[2] = creatures[2]!.id
+
+	return {
+		version: 2,
+		party,
+		boxes: [
+			{ name: 'Box 1', slots: Array(30).fill(null) as (string | null)[] },
+			{ name: 'Box 2', slots: Array(30).fill(null) as (string | null)[] },
+		],
+		creatures,
+		eggs: [],
+		dex: [],
+		bag: { items: [] },
+		stats: {
+			totalTurns: 10,
+			consecutiveDays: 5,
+			lastActiveDate: new Date().toISOString().split('T')[0],
+			totalEggsObtained: 0,
+			totalEvolutions: 0,
+			battlesWon: 3,
+			battlesLost: 1,
+		},
+	}
+}
+
+// ─── Default data ───
 
 describe('getDefaultBuddyData', () => {
 	test('returns v2 data with correct structure', async () => {
@@ -30,3 +92,236 @@ describe('getDefaultBuddyData', () => {
 		expect(creature.pokeball).toBe('pokeball')
 	})
 })
+
+// ─── Party operations ───
+
+describe('addToParty', () => {
+	test('adds creature to first empty slot', () => {
+		const data = makeData()
+		const result = addToParty(data, 'new-creature')
+		expect(result.added).toBe(true)
+		expect(result.data.party[1]).toBe('new-creature')
+	})
+
+	test('returns false when party is full', () => {
+		const data = makeData()
+		data.party = ['c1', 'c2', 'c3', 'c4', 'c5', 'c6']
+		const result = addToParty(data, 'new-creature')
+		expect(result.added).toBe(false)
+	})
+})
+
+describe('removeFromParty', () => {
+	test('removes creature at index', () => {
+		const data = makeData(2)
+		const updated = removeFromParty(data, 1)
+		expect(updated.party[1]).toBeNull()
+	})
+
+	test('does nothing for out-of-bounds index', () => {
+		const data = makeData()
+		const updated = removeFromParty(data, 10)
+		expect(updated.party).toEqual(data.party)
+	})
+})
+
+describe('swapPartySlots', () => {
+	test('swaps two party slots', () => {
+		const data = makeData(2)
+		const updated = swapPartySlots(data, 0, 1)
+		expect(updated.party[0]).toBe('creature-1')
+		expect(updated.party[1]).toBe('creature-0')
+	})
+})
+
+describe('setActivePartyMember', () => {
+	test('swaps creature to slot 0', () => {
+		const data = makeData(2)
+		const updated = setActivePartyMember(data, 'creature-1')
+		expect(updated.party[0]).toBe('creature-1')
+		expect(updated.party[1]).toBe('creature-0')
+	})
+
+	test('no change if already active', () => {
+		const data = makeData()
+		const updated = setActivePartyMember(data, 'creature-0')
+		expect(updated).toEqual(data)
+	})
+})
+
+// ─── PC Box operations ───
+
+describe('depositToBox', () => {
+	test('deposits creature to first empty box slot', () => {
+		const data = makeData()
+		const result = depositToBox(data, 'box-creature')
+		expect(result.deposited).toBe(true)
+		expect(result.data.boxes[0]!.slots[0]).toBe('box-creature')
+	})
+
+	test('fills second box when first is full', () => {
+		const data = makeData()
+		data.boxes[0]!.slots = Array(30).fill('x')
+		const result = depositToBox(data, 'box-creature')
+		expect(result.deposited).toBe(true)
+		expect(result.data.boxes[1]!.slots[0]).toBe('box-creature')
+	})
+})
+
+describe('withdrawFromBox', () => {
+	test('withdraws creature from box', () => {
+		const data = makeData()
+		data.boxes[0]!.slots[5] = 'box-creature'
+		const result = withdrawFromBox(data, 'box-creature')
+		expect(result.withdrawn).toBe(true)
+		expect(result.data.boxes[0]!.slots[5]).toBeNull()
+	})
+
+	test('returns false when creature not in boxes', () => {
+		const data = makeData()
+		const result = withdrawFromBox(data, 'nonexistent')
+		expect(result.withdrawn).toBe(false)
+	})
+})
+
+describe('moveInBox', () => {
+	test('moves creature between slots', () => {
+		const data = makeData()
+		data.boxes[0]!.slots[0] = 'moving-creature'
+		const updated = moveInBox(data, 0, 0, 0, 5)
+		expect(updated.boxes[0]!.slots[0]).toBeNull()
+		expect(updated.boxes[0]!.slots[5]).toBe('moving-creature')
+	})
+
+	test('does nothing for empty source slot', () => {
+		const data = makeData()
+		const updated = moveInBox(data, 0, 0, 0, 5)
+		expect(updated).toEqual(data)
+	})
+})
+
+describe('renameBox', () => {
+	test('renames a box', () => {
+		const data = makeData()
+		const updated = renameBox(data, 0, 'My Box')
+		expect(updated.boxes[0]!.name).toBe('My Box')
+	})
+})
+
+describe('findCreatureLocation', () => {
+	test('finds creature in party', () => {
+		const data = makeData()
+		const loc = findCreatureLocation(data, 'creature-0')
+		expect(loc).toEqual({ area: 'party', slot: 0 })
+	})
+
+	test('finds creature in box', () => {
+		const data = makeData()
+		data.boxes[0]!.slots[3] = 'box-creature'
+		const loc = findCreatureLocation(data, 'box-creature')
+		expect(loc).toEqual({ area: 'box', slot: 3, boxIndex: 0 })
+	})
+
+	test('returns null for nonexistent', () => {
+		const data = makeData()
+		expect(findCreatureLocation(data, 'nonexistent')).toBeNull()
+	})
+})
+
+describe('releaseCreature', () => {
+	test('removes creature from party and creatures array', () => {
+		const data = makeData(2)
+		const updated = releaseCreature(data, 'creature-1')
+		expect(updated.creatures.find(c => c.id === 'creature-1')).toBeUndefined()
+	})
+})
+
+describe('getTotalCreatureCount', () => {
+	test('returns creature count', () => {
+		expect(getTotalCreatureCount(makeData(3))).toBe(3)
+	})
+})
+
+describe('getAllCreatureIds', () => {
+	test('returns all ids', () => {
+		expect(getAllCreatureIds(makeData(2))).toEqual(['creature-0', 'creature-1'])
+	})
+})
+
+// ─── Bag operations ───
+
+describe('addItemToBag', () => {
+	test('adds new item', () => {
+		const data = makeData()
+		const updated = addItemToBag(data, 'potion', 3)
+		expect(updated.bag.items).toEqual([{ id: 'potion', count: 3 }])
+	})
+
+	test('stacks existing item', () => {
+		const data = makeData()
+		const withItem = addItemToBag(data, 'potion', 2)
+		const stacked = addItemToBag(withItem, 'potion', 3)
+		expect(stacked.bag.items[0]!.count).toBe(5)
+	})
+})
+
+describe('removeItemFromBag', () => {
+	test('removes item quantity', () => {
+		const data = makeData()
+		const withItem = addItemToBag(data, 'potion', 5)
+		const result = removeItemFromBag(withItem, 'potion', 3)
+		expect(result.removed).toBe(true)
+		expect(result.data.bag.items[0]!.count).toBe(2)
+	})
+
+	test('removes item entirely when count reaches 0', () => {
+		const data = makeData()
+		const withItem = addItemToBag(data, 'potion', 2)
+		const result = removeItemFromBag(withItem, 'potion', 2)
+		expect(result.removed).toBe(true)
+		expect(result.data.bag.items.length).toBe(0)
+	})
+
+	test('returns false when not enough items', () => {
+		const data = makeData()
+		const withItem = addItemToBag(data, 'potion', 1)
+		const result = removeItemFromBag(withItem, 'potion', 5)
+		expect(result.removed).toBe(false)
+	})
+
+	test('returns false for nonexistent item', () => {
+		const data = makeData()
+		const result = removeItemFromBag(data, 'potion', 1)
+		expect(result.removed).toBe(false)
+	})
+})
+
+describe('getItemCount', () => {
+	test('returns count for existing item', () => {
+		const data = makeData()
+		const withItem = addItemToBag(data, 'potion', 3)
+		expect(getItemCount(withItem, 'potion')).toBe(3)
+	})
+
+	test('returns 0 for nonexistent item', () => {
+		expect(getItemCount(makeData(), 'potion')).toBe(0)
+	})
+})
+
+// ─── Stats ───
+
+describe('updateDailyStats', () => {
+	test('same day does not increment consecutive', () => {
+		const data = makeData()
+		const updated = updateDailyStats(data)
+		expect(updated.stats.consecutiveDays).toBe(data.stats.consecutiveDays)
+	})
+})
+
+describe('incrementTurns', () => {
+	test('increments totalTurns by 1', () => {
+		const data = makeData()
+		const updated = incrementTurns(data)
+		expect(updated.stats.totalTurns).toBe(data.stats.totalTurns + 1)
+	})
+})