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 Goldziher/ai-rulez --skill ffi-and-language-interopgit clone --depth 1 https://github.com/Goldziher/ai-rulezWrote 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/goldziher/ai-rulez/ffi-and-language-interop)<a href="https://agentmods.dev/skills/goldziher/ai-rulez/ffi-and-language-interop"><img src="https://agentmods.dev/badge/skills/goldziher/ai-rulez/ffi-and-language-interop/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/goldziher/ai-rulez/ffi-and-language-interop"><img src="https://agentmods.dev/badge/skills/goldziher/ai-rulez/ffi-and-language-interop.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00066 | $0.00267 |
| Opus 5 | $0.00033 | $0.00133 |
| Sonnet 5 | $0.00013 | $0.00053 |
| Haiku 4.5 | $0.00007 | $0.00027 |
Grade A, and why
ffi-and-language-interop 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 12d 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.
What it actually says
- Every pointer has one owner, documented with
SAFETYcomments or host-language ownership docs. - Use opaque handles across native boundaries. Do not expose Rust, C++, or host-runtime internals directly.
- Check all nullable pointers before use and return explicit errors for invalid handles or null inputs.
- Provide allocate/free pairs for every caller-owned allocation and document which side frees each value.
- Every unsafe block must state the invariant, why it holds, and what would make it invalid.
- Generate C headers or native declarations from source when possible, and make CI verify generated files are current.
- Treat the C ABI or equivalent native ABI as the stable contract for downstream bindings.
- Freeze native struct layouts across compatible releases, and version breaking ABI changes deliberately.
- Convert native errors to host exceptions, result objects, or idiomatic error values at every boundary.
- Preserve diagnostic context across boundaries: message, numeric code when available, source operation, and cause chain.
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.
- 12d ago First seen · 16 lines · 66 tokens per session scan A 260b0512b01d
ffi-and-language-interop is a skill published in the GitHub repository Goldziher/ai-rulez (141 stars, last pushed 4d ago), licensed MIT. It adds 66 tokens to every session and 267 once invoked, about $0.0003 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 2026-08-30.
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