What is presets.dev rust.instructions.md?

Path-specific guidance for Rust projects, covering ownership, errors, asynchronous code, project structure, and supported compiler versions. Rust is a programming language that checks memory use and concurrency rules while code is compiled.

Use it when adding or changing Rust code, especially code involving borrowed data, errors, asynchronous operations, unsafe blocks, or foreign-function interfaces. It also guides where code belongs and how libraries and programs should report errors.

It gives coding agents consistent rules for working within an existing Rust project without changing dependency or compiler requirements unnecessarily.

How beel-collab/presets.dev configures GitHub Copilot

Reuse

Borrowing it

Nothing to install: this file belongs to beel-collab/presets.dev. 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/beel-collab/presets.dev/main/release/rust/native/copilot/.github/instructions/rust.instructions.md

Clone the repo

git clone --depth 1 https://github.com/beel-collab/presets.dev

Made for: GitHub Copilot.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/beel-collab/presets.dev/rust/github.svg)](https://agentmods.dev/instructions/beel-collab/presets.dev/rust)

Your own site

<a href="https://agentmods.dev/instructions/beel-collab/presets.dev/rust"><img src="https://agentmods.dev/badge/instructions/beel-collab/presets.dev/rust/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/beel-collab/presets.dev/rust"><img src="https://agentmods.dev/badge/instructions/beel-collab/presets.dev/rust.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 799 This file is loaded in full into every session.

When invoked 799 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00799	$0.00799
Opus 5.5	$0.00320	$0.00320
Sonnet 5.5	$0.00160	$0.00160
Haiku 4.5	$0.00080	$0.00080

Measured today against content hash 1201dfa42e8b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

presets.dev rust.instructions.md 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 today.

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.

release/rust/native/copilot/.github/instructions/rust.instructions.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Rust Copilot Instructions: Ownership, Errors and Async

Path-specific Copilot instructions for Rust. They apply through applyTo and leave .github/copilot-instructions.md in place.

Updated for Rust 1.100.0, Nov 2026

Do not upgrade dependencies or the framework version unless the task asks.

Stay on the rust-toolchain and the MSRV in Cargo.toml. Rust 1.100.0 stabilizes the never type and custom allocators. The 1.99 C-ABI variadics and raw-pointer layout APIs are already stable. Those FFI and layout APIs are not a reason to rewrite safe Rust. Do not raise the MSRV just because 1.100 exists. Read Cargo.toml before you add a crate.

Project shape

A library crate returns Result. A binary's main decides how to exit. Modules follow the existing tree. unsafe lives in the smallest block that needs it, with a comment that states the invariant. Do not use unsafe to avoid the borrow checker.

Prefer borrowing. Clone when the ownership story is actually a copy, and say why if the clone is on a hot path.

Errors

Library code does not unwrap or expect on a path a caller can trigger. expect is for a bug in the program, with a message that explains the broken invariant. Use the project's error type. ? propagates. A match that drops the error and returns a default hides a failure.

Async

An async function is cancel-safe at its await points, or it documents that it is not. Cancel safety is what happens if the future is dropped at an .await. It is separate from which mutex you hold.

Do not hold a std::sync::Mutex or a parking_lot guard across an .await. Those guards are !Send, so the future cannot be spawned on a multi-thread runtime. Holding one also blocks a worker thread and can deadlock. tokio::sync::Mutex is the lock you may hold across .await. A spawned task has a join handle or a structured scope. Blocking work does not run on the async runtime. Use the project's spawn_blocking helper.

A timeout cancels the inner work. Dropping a future should release the resources it holds.

Read the full file on GitHub · 65 lines

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.

today First seen · 65 lines · 799 tokens per session scan A 1201dfa42e8b

Subscribe to this mod's changes

presets.dev rust.instructions.md is an instructions file published in the GitHub repository beel-collab/presets.dev (3 stars, last pushed yesterday), licensed MIT. It adds 799 tokens to every session, about $0.0032 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 2026-11-13.

Languages Rust agents antigravity cline codex copilot

presets.dev rust.instructions.md next to 6 instructions from other repositories
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presets.dev: Instructions file for GitHub Copilot