What is rust-system-calls?

A guide for using bunsys to make system calls and handle files in Rust. System calls are direct requests to operating-system services, such as opening a file.

Use it when implementing file operations, opening file descriptors, or working on other system-call paths in Rust.

It helps code follow the required bunsys path instead of using Rust's standard file library or the libc library.

rust-system-calls — Skill by oven-sh

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/oven-sh/bun/rust-system-calls

Any agent

npx skills add oven-sh/bun --skill rust-system-calls

Clone the repo

git clone --depth 1 https://github.com/oven-sh/bun

Made for: Claude Code, Codex.

Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,111 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. Scan, not verified.

Origin unknown 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.

Model	Per session	Once invoked
Fable 5	$0.00042	$0.01111
Opus 5	$0.00021	$0.00556
Sonnet 5	$0.00008	$0.00222
Haiku 4.5	$0.00004	$0.00111

Measured 2d ago against content hash 3f7ccb3f4c27, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

rust-system-calls 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.

.claude/skills/rust-system-calls/SKILL.md · 97 lines

The source is not reproduced here

No licence file

Read it on GitHub

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.

2d ago First seen · 97 lines · 42 tokens per session scan A 3f7ccb3f4c27

Subscribe to this mod's changes

rust-system-calls is a skill published in the GitHub repository oven-sh/bun (95,832 stars, last pushed today), with no licence file. It adds 42 tokens to every session and 1,111 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 2026-08-30.

Languages bun bundler javascript javascriptcore jsx nodejs

rust-system-calls

Getting it into your agent

What it costs to keep this loaded

Grade A, and why

Nothing flagged

The source is not reproduced here

No licence file

What this file has done since we first saw it

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