wassette: Skill for Claude Code

.agents/skills/rust-code-style/SKILL.md

rust-code-style is a skill for Claude Code from microsoft/wassette. It costs 68 tokens per session (414 once invoked), scanned B, original, MIT.

A set of coding conventions for writing and refactoring Rust in the Wassette repository, including error handling, shared state, tests, and code checks.

In plain words
What is it for?
Use it when adding or changing Rust files, writing tests, handling errors, managing dependencies, or running the repository's formatting and linting commands.
Why use it?
It gives contributors consistent rules for readable code and catches formatting, lint, and unused-dependency problems before changes are committed.

Skill for Claude Code ✓ vendor

Written for Claude Code: allowed-tools in frontmatter. Also seen: installed under .agents/ (shared by several agents).

This is microsoft/wassette's own configuration. It tells Claude Code how to work on wassette itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything wassette configures →

About the project

microsoft/wassette is a runtime that loads WebAssembly Components as tools exposed through the Model Context Protocol (MCP), an interface that lets AI agents use external capabilities. It is for extending coding agents with reusable tools while isolating those tools in a Wasmtime security sandbox. The catalogue skills, instructions, and agent help configure and operate Wassette with supported MCP clients.

microsoft/wassette · 972 stars · on GitHub · microsoft.github.io

Reuse

Borrowing it

Nothing to install: this file belongs to microsoft/wassette. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/microsoft/wassette/main/.agents/skills/rust-code-style/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/microsoft/wassette

Made for: Claude Code.

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 rust-code-style

README.md
[![agentmods](https://agentmods.dev/badge/skills/microsoft/wassette/rust-code-style/github.svg)](https://agentmods.dev/skills/microsoft/wassette/rust-code-style)
Your own site
<a href="https://agentmods.dev/skills/microsoft/wassette/rust-code-style"><img src="https://agentmods.dev/badge/skills/microsoft/wassette/rust-code-style/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.

agentmods 80×15 button for rust-code-style

Your own site · 80×15
<a href="https://agentmods.dev/skills/microsoft/wassette/rust-code-style"><img src="https://agentmods.dev/badge/skills/microsoft/wassette/rust-code-style.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 414 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

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 →

  • high Anti-Refusal · line 38
    Skill instructs the agent to omit warnings, disclaimers, or ethical commentary. Stripping safety caveats hides risk from the user and is a common jailbreak preamble.
    Fix: Remove instructions that suppress warnings, disclaimers, or ethical commentary. Let the agent surface safety-relevant caveats to the user.
How audits are shown
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 $0.00068 $0.00414
Opus 5.5 $0.00027 $0.00166
Sonnet 5.5 $0.00014 $0.00083
Haiku 4.5 $0.00007 $0.00041

Measured 2mo ago against content hash fb296fabc6b0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

rust-code-style scanned grade B with 1 finding 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 2mo 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.

Strips warnings and disclaimersmediumAnti-refusal

Omitting safety caveats hides risk from the user and is a common jailbreak preamble.

Write code that passes `cargo clippy` without warnings.
.agents/skills/rust-code-style/SKILL.md · 44 lines

What it actually says

rust-code-style skill

Apply Wassette's Rust conventions when writing or refactoring .rs files.

Best practices

  • Single responsibility: each function and struct has one clear purpose.
  • DRY: extract shared logic into reusable functions or modules.
  • Descriptive naming: name functions, variables, and types for readability.
  • Unit tests: cover every public function and its edge cases.
  • Keep it simple: prefer straightforward solutions over clever complexity.
  • Dependencies: manage them carefully in Cargo.toml; avoid unnecessary ones that bloat the project.
  • Error handling: use anyhow to add context and stack traces.
  • Traits and generics: use traits for shared behavior and generics for reusable, type-safe, extensible APIs.
  • Thread safety: use stdlib primitives like Arc and Mutex for shared state.
  • Performance: choose appropriate data types, e.g. &str over String when possible.

Formatting and linting

Always run before committing:

cargo +nightly fmt          # Format (nightly toolchain required)
cargo clippy --workspace    # Lint; resolve every warning
cargo machete               # Check for unused dependencies

Write code that passes cargo clippy without warnings.

Every .rs file must start with the Microsoft copyright header. See the copyright-headers skill for the exact format and the automated script.

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. 2mo ago First seen · 44 lines · 68 tokens per session scan B fb296fabc6b0

Subscribe to this mod's changes

rust-code-style is a skill published in the GitHub repository microsoft/wassette (972 stars, last pushed 3d ago), licensed MIT. It adds 68 tokens to every session and 414 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it B with 1 finding (strips warnings and disclaimers). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.