Current compliance date: 2026-02-21

Rust Development Skill

This skill enforces structured, guideline-driven Rust development. It ensures all Rust code strictly follows the appropriate Microsoft-style rules, documentation formats, and quality constraints.

Mandatory Workflow

This skill MUST be invoked for ANY Rust action, including:

• Creating new .rs files (even minimal examples like Hello World)
• Modifying existing .rs files (any change, no matter how small)
• Reviewing, refactoring, or rewriting Rust code

Which guideline to read and when

Before writing or modifying Rust code, the agent must load ONLY the guideline files that apply to the requested task, using segmented reading (offset and limit) when needed.

Guidelines and when they apply

1. 01_ai_guidelines.md

Use when the Rust code involves AI agents, LLM-driven code generation, making APIs easier for AI systems, comprehensive documentation, or strong type systems that help AI avoid mistakes.

2. 02_application_guidelines.md

Use when working on application-level error handling with anyhow or eyre, CLI tools, desktop applications, performance optimization using mimalloc allocator, or user-facing features.

3. 03_documentation.md

Use when writing public API documentation and doc comments, creating canonical documentation sections (Examples, Errors, Panics, Safety), structuring module-level documentation, or using #[doc(inline)] annotations.

4. 04_ffi_guidelines.md

Use when loading multiple Rust-based dynamic libraries, creating FFI boundaries, sharing data between different Rust compilation artifacts, or dealing with portable vs non-portable data types across DLL boundaries.

5. 05_library_guidelines.md

Use when creating or modifying Rust libraries, structuring a crate, designing public APIs, or making dependency decisions.

6. 06_performance_guidelines.md

Use when profiling hot paths, optimizing for throughput and CPU efficiency, managing allocation patterns and memory usage, or implementing yield points in long-running async tasks.

7. 07_safety_guidelines.md

Use when writing unsafe code for novel abstractions, performance, or FFI, ensuring soundness, preventing undefined behavior, documenting safety requirements, or reviewing unsafe blocks with Miri.

8. 08_universal_guidelines.md

Use in ALL Rust tasks. Defines general best practices, style, naming, organizational conventions, and foundational principles.

9. 09_libraries_building_guidelines.md

Use when creating reusable library crates, managing Cargo features, building native -sys crates for C interop, or ensuring libraries work out-of-the-box on all platforms.

10. 10_libraries_interoperability_guidelines.md

Use when exposing public APIs, managing external dependencies, designing types for Send/Sync compatibility, avoiding leaking third-party types, or creating escape hatches for native handle interop.

11. 11_libraries_resilience_guidelines.md

Use when avoiding statics and thread-local state, making I/O mockable, preventing glob re-exports, or feature-gating test utilities.

12. 12_libraries_ux_guidelines.md

Use when designing user-friendly library APIs, managing error types, creating runtime abstractions and trait-based designs, or structuring crate organization.

Coding Rules

1. Load the necessary guideline files BEFORE ANY RUST CODE GENERATION.
2. Apply the required rules from the relevant guidelines.
3. Apply the M-CANONICAL-DOCS documentation format (summary sentence < 15 words, then extended docs, Examples, Errors, Panics, Safety, Abort sections as applicable).
4. Comments must ALWAYS be written in American English, unless the user explicitly requests a different language.
5. If the file is fully compliant, add a comment: // Rust guideline compliant 2026-02-21