lcu-api

name	lcu-api
description	League of Legends LCU (League Client Update) API reference. Use when working with LCU endpoints, champ select, skin selection, gameflow phases, ownership checks, lobby, matchmaking, store, collections, or any fetch/PATCH calls to the local client API.
allowed-tools	Read, Grep, Glob
argument-hint	["endpoint or topic"]

LCU API Reference

Complete reference for the League Client Update (LCU) local REST API. All schemas validated against the official swagger definition (dysolix/hasagi-types).

The LCU API is a local HTTPS REST API exposed by the League of Legends client on 127.0.0.1 with a random port. In CEF plugin context, use relative paths: fetch('/lol-champ-select/v1/session').

Supporting Files

• all-endpoints.md — Every LCU endpoint grouped by plugin (~1700 lines, 90+ plugins)
• schemas.md — All schema/type definitions with fields and types (~950 schemas)
• endpoints.md — Detailed docs for commonly used endpoints with example JSON

Use Read or Grep on these files to find specific endpoint or schema details.

Swagger Source

https://raw.githubusercontent.com/dysolix/hasagi-types/main/swagger.json

Key Conventions

• Skin IDs: Base/default skin = championId * 1000. Example: Ahri (103) → base skin 103000.
• PATCH body field: Skin selection uses selectedSkinId (NOT skinId). Confirmed across all schema variants.
• Ownership check: s.ownership.owned === true for purchased. s.ownership.rental.rented === true for rented/boosted.
• Local player in session: session.myTeam.find(p => p.cellId === session.localPlayerCellId)
• WebSocket events: context.socket.observe(path, callback) where callback receives { eventType, uri, data }.
• Gameflow phases (lifecycle order): None → Lobby → Matchmaking → ReadyCheck → ChampSelect → GameStart → InProgress → WaitingForStats → PreEndOfGame → EndOfGame

Plugin Index

Major LCU plugins and what they cover:

Plugin prefix	Domain
lol-champ-select	Champion select session, picks, bans, skin selection, swaps
lol-champ-select-legacy	Legacy champ select (same structure, older endpoints)
lol-champions	Champion/skin inventories, ownership data
lol-game-data	Static game data (champion info, skin lists, items)
lol-summoner	Current summoner info, profile
lol-gameflow	Game lifecycle phases and session
lol-matchmaking	Queue, ready check, search
lol-lobby	Lobby management, invites, party
lol-lobby-team-builder	Team builder / draft lobby
lol-collections	Player collections (ward skins, spells, etc.)
lol-catalog	Store catalog, items, bundles
lol-store	Store operations, purchases
lol-inventory	Player inventory (skins, champions, etc.)
lol-loot	Hextech crafting, loot
lol-chat	Chat, friends, conversations
lol-ranked	Ranked stats, tiers, LP
lol-perks	Runes/perks pages
lol-loadouts	Item sets, loadouts
lol-cosmetics	TFT cosmetics (companions, arenas, etc.)
lol-clash	Clash tournaments
lol-challenges	Challenges system
lol-champion-mastery	Mastery points and levels
lol-end-of-game	Post-game stats
lol-event-hub	Events, passes, reward tracks
lol-active-boosts	Active XP/skin boosts
lol-patch	Client patching status
lol-player-behavior	Honor, restrictions, reform cards
lol-pre-end-of-game	Pre-end-of-game sequence
lol-replays	Replay downloads and playback
lol-settings	Client settings
lol-suggested-players	Suggested players to play with
lol-tft	TFT-specific endpoints

Critical Schemas (Quick Ref)

PATCH /lol-champ-select/v1/session/my-selection body

Schema: TeamBuilderDirect-ChampSelectMySelection

{
  "selectedSkinId": 0,   // int32 — THE correct field name
  "spell1Id": 0,         // uint64 (optional)
  "spell2Id": 0          // uint64 (optional)
}

Champ select player (in session.myTeam[])

Schema: TeamBuilderDirect-ChampSelectPlayerSelection

Key fields: cellId (int64), championId (int32), selectedSkinId (int32), summonerId (uint64), assignedPosition (string), spell1Id, spell2Id, gameName, tagLine, puuid

Skin object (from inventories endpoint)

Schema: LolChampionsCollectionsChampionSkin

Key fields: id (int32), championId (int32), name (string), isBase (boolean), ownership → { owned, rental: { rented } }, chromas[], splashPath, tilePath

Ownership

Schema: LolChampionsCollectionsOwnership

Fields: owned (boolean), loyaltyReward (boolean), xboxGPReward (boolean), rental → { rented, endDate, purchaseDate, winCountRemaining, gameId }

Summoner

Schema: LolSummonerSummoner

Key fields: summonerId (uint64), accountId (uint64), puuid (string), gameName (string), tagLine (string), displayName, summonerLevel, profileIconId

Gameflow phase

Schema: LolGameflowGameflowPhase (enum string)

Values: None, Lobby, Matchmaking, CheckedIntoTournament, ReadyCheck, ChampSelect, GameStart, FailedToLaunch, InProgress, Reconnect, WaitingForStats, PreEndOfGame, EndOfGame, TerminatedInError