12 tools with clear verb-noun naming (join_game, make_move, set_name, etc.) and consistent parameter schemas. Descriptions are present but brief (avg ~80 chars, below the 194-char baseline). All tools have input schemas with type definitions and parameter descriptions. However, output schemas are not documented, LLMs cannot predict response structure. No error handling guidance, no recovery hints, and no distinction between retryable vs fatal errors. Security model unclear: playerId is passed as a parameter rather than server-injected, risking exposure in logs. Tool composition is sound (single responsibility), but descriptions lack WHEN/WHY context that LLMs need for selection.

• Document output schemas for all tools. Define PlayerView, JoinResult, GameView, InviteView structures with field types and descriptions. Include all IDs needed for chaining (playerId, inviteId, gameId).
• Expand descriptions to 80 - 150 chars. Add WHEN context: 'Invite another player in the lobby to start a game. Call after join_game and only if both players are in the lobby.' Include state transitions.
• Add error handling guidance. E.g., 'If invite fails: player offline (retry later), already in game (suggest play_vs_model), or invalid targetId (call get_state to list available players).'
• Inject playerId server-side via session/bearer token instead of parameter. Reduces log exposure and simplifies LLM calls. Alternatively, document that playerId is ephemeral and session-scoped.
• Add dry-run or confirmation for close_session. Return 'Session will be closed. Call confirm_close_session(playerId, confirmationToken) to proceed.' Prevents accidental termination.