gate-check

gate-check is a skill for Claude Code, OpenCode from TraftG/opencode-game-studio. It costs 29 tokens per session (2,191 once invoked), scanned A, original, MIT.

A development-phase readiness check for a game project. It examines required documents, quality standards, and blockers, then gives a PASS, CONCERNS, or FAIL verdict.

In plain words
What is it for?
Use it to validate transitions from concept through release, record the new stage after a pass, and list missing evidence or blocking problems.
Why use it?
It shows whether the project is ready to move forward and identifies what must be fixed or prepared first.

Skill for Claude CodeOpenCode

Written for Claude Code and OpenCode: allowed-tools in frontmatter, but also installed under .opencode/. Also seen: mentions OpenCode.

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/traftg/opencode-game-studio/gate-check
Any agent
npx skills add TraftG/opencode-game-studio --skill gate-check
Clone the repo
git clone --depth 1 https://github.com/TraftG/opencode-game-studio

Made for: Claude Code, OpenCode.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for gate-check

README.md
[![agentmods](https://agentmods.dev/badge/skills/traftg/opencode-game-studio/gate-check.svg)](https://agentmods.dev/skills/traftg/opencode-game-studio/gate-check)
Your own site
<a href="https://agentmods.dev/skills/traftg/opencode-game-studio/gate-check"><img src="https://agentmods.dev/badge/skills/traftg/opencode-game-studio/gate-check.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,191 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00029 $0.02191
Opus 5 $0.00015 $0.01095
Sonnet 5 $0.00006 $0.00438
Haiku 4.5 $0.00003 $0.00219

Measured 2d ago against content hash b401873622fd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

gate-check scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

.opencode/skills/gate-check/SKILL.md · 253 lines

How it starts

The opening of the file, as written. The whole thing — 253 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Phase Gate Validation

This skill validates whether the project is ready to advance to the next development phase. It checks for required artifacts, quality standards, and blockers.

Distinct from /project-stage-detect: That skill is diagnostic ("where are we?"). This skill is prescriptive ("are we ready to advance?" with a formal verdict).

Production Stages (7)

The project progresses through these stages:

  1. Concept — Brainstorming, game concept document
  2. Systems Design — Mapping systems, writing GDDs
  3. Technical Setup — Engine config, architecture decisions
  4. Pre-Production — Prototyping, vertical slice validation
  5. Production — Feature development (Epic/Feature/Task tracking active)
  6. Polish — Performance, playtesting, bug fixing
  7. Release — Launch prep, certification

When a gate passes, write the new stage name to production/stage.txt (single line, e.g. Production). This updates the status line immediately.


1. Parse Arguments

  • With argument: /gate-check production — validate readiness for that specific phase
  • No argument: Auto-detect current stage using the same heuristics as /project-stage-detect, then validate the NEXT phase transition

2. Phase Gate Definitions

Gate: Concept → Systems Design

Required Artifacts:

  • design/gdd/game-concept.md exists and has content
  • Game pillars defined (in concept doc or design/gdd/game-pillars.md)

Quality Checks:

  • Game concept has been reviewed (/design-review verdict not MAJOR REVISION NEEDED)
  • Core loop is described and understood
  • Target audience is identified

Gate: Systems Design → Technical Setup

Required Artifacts:

  • Systems index exists at design/gdd/systems-index.md with at least MVP systems enumerated
  • At least 1 GDD in design/gdd/ (beyond game-concept.md and systems-index.md)

Quality Checks:

  • GDD(s) pass design review (8 required sections present)
  • System dependencies are mapped in the systems index
  • MVP priority tier is defined

Read the full file on GitHub · 253 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 253 lines · 29 tokens per session scan A b401873622fd

Subscribe to this mod's changes

gate-check is a skill published in the GitHub repository TraftG/opencode-game-studio (38 stars, last pushed 4mo ago), licensed MIT. It adds 29 tokens to every session and 2,191 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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