diff --git a/src/lib/components/party/Party.svelte b/src/lib/components/party/Party.svelte
index fbcf98cb..c9b59216 100644
--- a/src/lib/components/party/Party.svelte
+++ b/src/lib/components/party/Party.svelte
@@ -15,10 +15,10 @@
 		useUpdateSummonUncap
 	} from '$lib/api/mutations/grid.mutations'
 
-	// Services (to be removed in Phase 4)
+	// Legacy services - kept only for swap/move operations and edit keys
+	// TODO: Remove once swap/move mutations are implemented
 	import { PartyService } from '$lib/services/party.service'
 	import { GridService } from '$lib/services/grid.service'
-	import { ConflictService } from '$lib/services/conflict.service'
 
 	import { createDragDropContext, type DragOperation } from '$lib/composables/drag-drop.svelte'
 	import WeaponGrid from '$lib/components/grids/WeaponGrid.svelte'
@@ -74,10 +74,9 @@
 	let editDialogOpen = $state(false)
 	let editingTitle = $state('')
 
-	// Services (Phase 4: to be removed)
+	// Legacy services - only for swap/move and edit keys
 	const partyService = new PartyService()
 	const gridService = new GridService()
-	const conflictService = new ConflictService()
 
 	// TanStack Query mutations
 	const deleteWeapon = useDeleteGridWeapon()
@@ -683,8 +682,7 @@
 		getEditKey: () => editKey,
 		services: {
 			partyService,
-			gridService: clientGridService, // Use client-side wrapper
-			conflictService
+			gridService: clientGridService // Uses TanStack Query mutations
 		},
 		openPicker: (opts: {
 			type: 'weapon' | 'summon' | 'character'
diff --git a/src/lib/utils/gridStateUpdater.ts b/src/lib/utils/gridStateUpdater.ts
deleted file mode 100644
index 6ceee096..00000000
--- a/src/lib/utils/gridStateUpdater.ts
+++ /dev/null
@@ -1,137 +0,0 @@
-/**
- * Grid state update utilities
- * Handles optimistic updates for uncap levels and other grid item properties
- */
-
-import type { Party } from '$lib/types/api/party'
-import type { GridService } from '$lib/services/grid.service'
-import type { GridItemType, GridCollection } from './gridOperations'
-import { getCollectionKey } from './gridOperations'
-
-export interface UncapUpdateParams {
-	gridItemId: string
-	uncapLevel?: number
-	transcendenceStep?: number
-}
-
-/**
- * Generic function to update uncap levels for any grid item type
- * Replaces updateCharacterUncap, updateWeaponUncap, updateSummonUncap
- *
- * @param itemType - Type of grid item (character, weapon, or summon)
- * @param params - Uncap update parameters
- * @param partyId - Party UUID
- * @param currentParty - Current party state
- * @param editKey - Optional edit key for authorization
- * @param gridService - Grid service instance
- * @returns Updated party with modified uncap levels
- *
- * @example
- * ```typescript
- * const updated = await updateGridItemUncap(
- *   'weapon',
- *   { gridItemId: 'abc123', uncapLevel: 4, transcendenceStep: 1 },
- *   party.id,
- *   party,
- *   editKey,
- *   gridService
- * )
- * ```
- */
-export async function updateGridItemUncap(
-	itemType: GridItemType,
-	params: UncapUpdateParams,
-	partyId: string,
-	currentParty: Party,
-	editKey: string | undefined,
-	gridService: GridService
-): Promise<Party> {
-	// Get configuration for this item type
-	const config = getGridItemConfig(itemType)
-
-	// Call appropriate service method
-	const response = await config.updateMethod(
-		gridService,
-		partyId,
-		params.gridItemId,
-		params.uncapLevel,
-		params.transcendenceStep,
-		editKey
-	)
-
-	// Extract updated item from response (handle both camelCase and snake_case)
-	const updatedItem = response[config.responseKey] || response[config.snakeCaseKey]
-	if (!updatedItem) return currentParty
-
-	// Update party state optimistically
-	return mergeUpdatedGridItem(currentParty, config.collectionKey, params.gridItemId, {
-		uncapLevel: updatedItem.uncapLevel ?? updatedItem.uncap_level,
-		transcendenceStep: updatedItem.transcendenceStep ?? updatedItem.transcendence_step
-	})
-}
-
-/**
- * Configuration map for grid item types
- */
-function getGridItemConfig(itemType: GridItemType) {
-	const configs = {
-		character: {
-			updateMethod: (gs: GridService, ...args: any[]) => gs.updateCharacterUncap(...args),
-			responseKey: 'gridCharacter',
-			snakeCaseKey: 'grid_character',
-			collectionKey: 'characters' as GridCollection
-		},
-		weapon: {
-			updateMethod: (gs: GridService, ...args: any[]) => gs.updateWeaponUncap(...args),
-			responseKey: 'gridWeapon',
-			snakeCaseKey: 'grid_weapon',
-			collectionKey: 'weapons' as GridCollection
-		},
-		summon: {
-			updateMethod: (gs: GridService, ...args: any[]) => gs.updateSummonUncap(...args),
-			responseKey: 'gridSummon',
-			snakeCaseKey: 'grid_summon',
-			collectionKey: 'summons' as GridCollection
-		}
-	}
-
-	return configs[itemType]
-}
-
-/**
- * Merges updates into a grid item within party state
- * Preserves immutability by creating new objects
- *
- * @param party - Current party state
- * @param collection - Collection key (characters, weapons, or summons)
- * @param itemId - Grid item ID to update
- * @param updates - Fields to update
- * @returns New party object with updates applied
- */
-function mergeUpdatedGridItem(
-	party: Party,
-	collection: GridCollection,
-	itemId: string,
-	updates: any
-): Party {
-	const updatedParty = { ...party }
-	const items = updatedParty[collection]
-
-	if (!items) return party
-
-	const itemIndex = items.findIndex((item: any) => item.id === itemId)
-	if (itemIndex === -1) return party
-
-	const existingItem = items[itemIndex]
-	if (!existingItem) return party
-
-	// Merge updates while preserving essential properties
-	items[itemIndex] = {
-		...existingItem,
-		...updates,
-		id: existingItem.id,
-		position: existingItem.position
-	}
-
-	return updatedParty
-}