Gearboy is an emulator and debugger for Game Boy, Game Boy Color, and Super Game Boy software, with an embedded MCP server for AI-assisted debugging and development. It is used by people running or developing these games across desktop systems, BSD, and RetroArch. The catalogue contains add-ons that connect coding agents to Gearboy.
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 drhelius/Gearboy --skill gearboy-romhackinggit clone --depth 1 https://github.com/drhelius/GearboyWrote 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/drhelius/gearboy/gearboy-romhacking)<a href="https://agentmods.dev/skills/drhelius/gearboy/gearboy-romhacking"><img src="https://agentmods.dev/badge/skills/drhelius/gearboy/gearboy-romhacking/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/drhelius/gearboy/gearboy-romhacking"><img src="https://agentmods.dev/badge/skills/drhelius/gearboy/gearboy-romhacking.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 7 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 | $0.00154 | $0.03167 |
| Opus 5.5 | $0.00062 | $0.01267 |
| Sonnet 5.5 | $0.00031 | $0.00633 |
| Haiku 4.5 | $0.00015 | $0.00317 |
Grade A, and why
gearboy-romhacking 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 1mo 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.
The source is not reproduced here
Licensed GPL-3.0
The repository is licensed GPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.
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.
- 1mo ago Changed 033fb8c49377
- 1mo ago First seen · 316 lines · 154 tokens per session scan A 8e0d9fd92640
gearboy-romhacking is a skill published in the GitHub repository drhelius/Gearboy (1,219 stars, last pushed yesterday), licensed GPL-3.0. It adds 154 tokens to every session and 3,167 once invoked, about $0.0006 per session on Opus 5.5. 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 2026-08-30.
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