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.
npx skills add hoatv2211/GameStudio-CodexKIT --skill game-feature-to-specgit clone --depth 1 https://github.com/hoatv2211/GameStudio-CodexKITWrote 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.
[](https://agentmods.dev/skills/hoatv2211/gamestudio-codexkit/game-feature-to-spec)<a href="https://agentmods.dev/skills/hoatv2211/gamestudio-codexkit/game-feature-to-spec"><img src="https://agentmods.dev/badge/skills/hoatv2211/gamestudio-codexkit/game-feature-to-spec/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/hoatv2211/gamestudio-codexkit/game-feature-to-spec"><img src="https://agentmods.dev/badge/skills/hoatv2211/gamestudio-codexkit/game-feature-to-spec.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00046 | $0.00770 |
| Opus 5 | $0.00023 | $0.00385 |
| Sonnet 5 | $0.00009 | $0.00154 |
| Haiku 4.5 | $0.00005 | $0.00077 |
Grade A, and why
game-feature-to-spec 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 10d 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.
How it starts
The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Game Feature to Spec
Overview
Convert an approved direction into an implementation-neutral contract that design, engineering, QA, art, data, and production can test.
When to use
Use after a feature option is selected and before tasks, code, content production, or schema changes begin.
When NOT to use
Do not use to choose among competing feature directions or to split an existing specification into ownership packets.
Required inputs and context discovery
Require approved option, player goal, non-goals, system boundaries, platform constraints, dependencies, persistence/network authority, content needs, tuning ownership, telemetry expectations, and playtest audience.
Safety and risk level
Specification writes are low-risk. Do not invent engine, backend, analytics, or database contracts; mark unresolved authority and schema decisions BLOCKED.
Workflow
- State purpose, player outcome, scope, and non-goals. Completion criterion: stakeholders can identify what is explicitly not being built.
- Define inputs, outputs, state transitions, authority, persistence, and failure behavior. Completion criterion: the feature can be represented as deterministic scenarios.
- Enumerate edge cases, abuse/exploit cases, accessibility, localization, and offline/network behavior. Completion criterion: risky branches have expected outcomes or BLOCKED owners.
- Define tuning levers, defaults, ownership, migration needs, and telemetry events. Completion criterion: designers can tune without hidden code changes where intended.
- Write acceptance and playtest criteria tied to observable behavior. Completion criterion: QA can derive tests without guessing product intent.
Evidence and output contract
Produce feature-spec.md with purpose, non-goals, I/O, states, authority, edge cases, tuning, telemetry, content, acceptance criteria, playtest criteria, dependencies, and open decisions.
Handoff contract
Record approved version, owners of open decisions, affected systems, required prototypes, schema risks, and the prompt for work-packet decomposition.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 10d ago First seen · 79 lines · 46 tokens per session scan A 42ee3f2302b8
game-feature-to-spec is a skill published in the GitHub repository hoatv2211/GameStudio-CodexKIT (3 stars, last pushed 3d ago), licensed MIT. It adds 46 tokens to every session and 770 once invoked, about $0.0002 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 2026-08-31.
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