Gat milestone

Skill Yuki001/game-dev-skills/gat/.claude/skills/gat-milestone

My personal agent skill repository, primarily focused on game development.

Install

npx -y skills add Yuki001/game-dev-skills --skill gat-milestone

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

no licenseNo license file was found in the repository. Code published without one is not open source by default, so using it at work is a question for whoever answers licensing questions where you are.

What its author says it does

Copied from the file, not written here

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.

SKILL.md

3.4 KB, as published. Nobody here has run it

Milestone

This skill plans milestone slices BEFORE per-system design and creates:

gat/milestone/milestone.md — the ordered milestone roadmap with status
gat/milestone/m{N}-<name>/ — per-milestone directory skeletons
gat/milestone/m{N}-<name>/m{N}-brief.md — milestone brief skeletons (all systems Pending, status planned)

It does NOT require any system GDD to exist. It does not create task lists, technical designs, prompt packs, or implementation files. Those belong to the downstream engineering workflow.

Phase 1: Validate Inputs

Fail if any of these are missing:

gat/overview/game.md
gat/overview/systems-index.md
gat/overview/art-direction.md

Do NOT fail when no system GDDs exist. Planning runs before design; the systems index's priorities and dependencies are sufficient input for slicing.

Read:

gat/overview/game.md
gat/overview/systems-index.md
gat/overview/art-direction.md
all existing gat/narrative/*.md (used to inform milestone boundaries)
.claude/docs/templates/plan/milestone.md
.claude/docs/templates/plan/m-brief.md
gat/milestone/milestone.md if it already exists
existing gat/milestone/m{N}-<name>/m{N}-brief.md files if any milestones are already planned

Phase 2: Hand Off To The Planner

Spawn gat-planner agent with all read content plus:

instruction to write or update gat/milestone/milestone.md as an ordered set of milestone slices (M01, M02, ...) with a status column (planned -> designing -> designed)
instruction to create a directory gat/milestone/m{N}-<name>/ for each planned milestone
instruction to author an m{N}-brief.md skeleton (template: .claude/docs/templates/plan/m-brief.md) for each milestone, listing every in-scope system with status Pending and the milestone status planned
instruction to add an internal iteration plan to each brief using the template's repeated subsections;
instruction NOT to write system GDDs, content-data docs, art docs, task lists, technical designs, prompt packs, or code
planning focus from argument if provided

The planner should:

choose a small set of meaningful milestones that can be handed off one stage at a time
give each milestone a clear goal, player-facing outcome, and named system set
define what is in scope and explicitly out of scope for each milestone
use the systems index priorities + dependencies + narrative structure to slice; it does not need per-system rule detail
include overview, narrative (scoped range), and content context needed by a downstream engineering workflow
avoid technical architecture, file plans, coding tasks, and implementation sequencing
set each new milestone's status to planned

Phase 3: Review

Summarize how many milestones were planned, which comes first, and which directories/briefs were created.

Use AskUserQuestion:

Start designing the first milestone (Recommended) → Tell the user to run /gat-design <first-milestone> <system> or /gat-design <first-milestone> (continue)
Stop here