> ## Documentation Index > Fetch the complete documentation index at: https://docs.d-sports.org/llms.txt > Use this file to discover all available pages before exploring further. # Buy a playbook upgrade node > Unknown nodeId returns 400 VALIDATION_ERROR. Already-owned nodes return 400 VALIDATION_ERROR (stale client state; never the already-played screen). Insufficient Playbooks returns 409 IDLE_INSUFFICIENT_BUZZ. Costs 1-3 Playbooks per the frozen node table. Idempotent per idempotencyKey. Optional X-Client-Version below minClientVersion returns 403 GAME_UPDATE_REQUIRED. ## OpenAPI ````yaml /api-reference/openapi.json post /api/v1/engage/games/locker-singularity/ledger/upgrades openapi: 3.1.0 info: title: D-Sports API description: >- Public API for the D-Sports fan engagement platform (PWA backend). Most endpoints require Clerk Bearer authentication. version: 1.0.0 servers: - url: https://app.d-sports.org description: Production - url: http://localhost:3004 description: Local development security: - bearerAuth: [] tags: - name: Auth description: Authentication and token exchange - name: Logout description: Session logout - name: Mobile auth description: OAuth flow for native apps - name: Teams description: Teams list and follow/unfollow - name: Leaderboard description: Leaderboards, seasons, winners, stats - name: Locker room description: Social feed posts, comments, reactions - name: Packs description: Packs list, purchase, open - name: User description: Profile, onboarding, follow, search, privacy - name: Quests description: Quests and progress - name: Rewards description: Rewards claim and redeem - name: Wallets description: Wallets and coin prices - name: Checkout description: Crypto and D-Sports Cash checkout - name: D-Sports Cash description: D-Sports Cash balance - name: Dashboard description: Dashboard stats and balance - name: Products description: Products and packs catalog - name: Webhooks description: RevenueCat webhook - name: Misc description: Image proxy, crypto prices, upload, feedback - name: Auth and onboarding description: Domain grouping for auth, profile, onboarding, and identity flows - name: Social and locker room description: Domain grouping for social feed, follows, and community interactions - name: Gamification description: >- Domain grouping for quests, leaderboards, points-facing outcomes, and rewards - name: Commerce and purchases description: >- Domain grouping for checkout, cash balance, webhooks, and store purchase flows - name: Collectibles and packs description: Domain grouping for pack lifecycle and collectible inventory - name: Wallet and web3 description: Domain grouping for wallet and crypto-support operations - name: Moderation and reporting description: >- Domain grouping for user-facing report submission and moderation-adjacent endpoints - name: Platform and infrastructure description: >- Domain grouping for utility, infrastructure, and platform support endpoints - name: Rep description: Fan / Club / Player / Direct Rep earn, breakdown, and ledger - name: Engage description: Engage-domain Rep and related mobile contracts - name: Admin description: Staff-only admin operations - name: Binders description: Digital binder inventory, PIN, and card transfer - name: Games description: Team mini-game catalog and play routes - name: Game Engine description: Engage native catalog and server-authoritative daily session lifecycle - name: Events description: Game schedule, Game Center, chat, presence, and ratings - name: Notifications description: Authenticated in-app inbox - name: Config description: Public catalogs and support matrices - name: Discovery description: Suggested fans and teams - name: Leagues description: League metadata and branding - name: Marketplace description: Listings, bids, offers, cart, and shop merchandising - name: KYC description: Identity verification session helpers paths: /api/v1/engage/games/locker-singularity/ledger/upgrades: post: tags: - Games - Game Engine - Engage summary: Buy a playbook upgrade node description: >- Unknown nodeId returns 400 VALIDATION_ERROR. Already-owned nodes return 400 VALIDATION_ERROR (stale client state; never the already-played screen). Insufficient Playbooks returns 409 IDLE_INSUFFICIENT_BUZZ. Costs 1-3 Playbooks per the frozen node table. Idempotent per idempotencyKey. Optional X-Client-Version below minClientVersion returns 403 GAME_UPDATE_REQUIRED. parameters: - name: X-Client-Version in: header required: false schema: type: string description: >- Native client semver. Below minClientVersion returns 403 GAME_UPDATE_REQUIRED. requestBody: required: true content: application/json: schema: type: object required: - nodeId - idempotencyKey properties: nodeId: type: string enum: - locker-room-10 - packs-25 - hockey-dailies-10 - micd-up-25 - locker-room-global-5 - micd-up-global-5 idempotencyKey: type: string format: uuid additionalProperties: false responses: '200': description: '{ ledger }' content: application/json: schema: type: object required: - ledger properties: ledger: $ref: '#/components/schemas/LedgerState' '400': description: VALIDATION_ERROR '401': description: UNAUTHORIZED '403': description: GAME_UPDATE_REQUIRED '404': description: GAME_UNKNOWN '409': description: IDLE_INSUFFICIENT_BUZZ security: - bearerAuth: [] components: schemas: LedgerState: type: object description: >- locker-singularity idle ledger wire state. Buzz counters are BigInt serialized as decimal strings. Additive-only wire evolution (d-sports-api#682). required: - buzz - lifetimeBuzz - cumulativeBuzz - playbooks - generators - milestonesClaimed - upgrades - rings - totalRings - prestigeCount - multiplier - prestigeUnlocked - version - lastSeenAt properties: buzz: type: string description: BigInt serialized as decimal string. lifetimeBuzz: type: string description: BigInt serialized as decimal string. cumulativeBuzz: type: string description: BigInt serialized as decimal string. playbooks: type: integer generators: type: array items: $ref: '#/components/schemas/IdleLedgerGeneratorState' milestonesClaimed: type: array items: type: string upgrades: type: array items: type: string rings: type: integer description: >- Most recent prestige grant (informational); totalRings is the cumulative balance. totalRings: type: integer prestigeCount: type: integer multiplier: type: number prestigeUnlocked: type: boolean version: type: integer lastSeenAt: type: string format: date-time IdleLedgerGeneratorState: type: object required: - generatorId - owned properties: generatorId: type: string enum: - rookie-card - foam-finger-stand - zamboni-fleet - banner-press owned: type: integer securitySchemes: bearerAuth: type: http scheme: bearer description: 'Clerk session token. Use Authorization: Bearer .' ````