Enforce OOP and DDD engineering constraints for C# and TypeScript game development. Use when implementing, refactoring, reviewing, or testing gameplay systems, combat, inventory, progression, quests, scenes, matches, player data, save/load flows, domain-controlled engine-view wrappers, domain models, aggregates, application services, repositories, vertical slices, public APIs, Context-based shared dependencies, or deterministic test seams. Preserve encapsulation, keep engine details outside Domain, avoid test-only production hooks, and deliver complete game behavior through public contracts.
Design one system within a specific milestone's scope: write the milestone-scoped system GDD, content data, and system art doc, and update the milestone brief's progress. Requires a mandatory milestone argument.
Plan milestone slices from overview + narrative alone (no system GDDs required), create per-milestone directory skeletons and briefs, and write gat/milestone/milestone.md. Runs before per-system design. Stops before technical design, task breakdown, or implementation.
Inspect the repo state and show a status panel across all milestones, recommending the earliest actionable next step in the workflow.
Generate images through OpenRouter's dedicated Image API. Use this skill whenever the user wants to create, render, generate, or save images with OpenRouter, including text-to-image, image-to-image/reference images, choosing OpenRouter image models, listing image models, setting resolution/aspect ratio/quality/output format, or passing provider-specific image options. Prefer the bundled Python script so API options are passed explicitly as command-line arguments instead of hand-written ad hoc curl requests.
Brainstorm a game idea through one-question-at-a-time designer interviews. Produces game.md, systems-index.md, and art-direction.md, or runs as discussion-only.
Develop game story and narrative through one-question-at-a-time writer interviews. Produces narrative docs under gat/narrative/ or runs as discussion-only. Use when the user wants story, plot, lore, worldbuilding, characters, quests, dialogue, narrative tone, or authored story content for a GAT game.
READ this skill when designing or planning any game system architecture — including combat, skills, AI, UI, multiplayer, narrative, or scene systems. Contains paradigm selection guides (DDD / Data-Driven / Prototype), system-specific design references, and mixing strategies. Works as a domain knowledge plugin alongside workflow skills (OpenSpec, SpecKit) or plan mode of an agent.