domain-embedded

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass, no license.

!`cat .cargo/config.toml 2>/dev/null || echo "No .cargo/config.toml found"`

Audit 0.4.1 · source sha f4ff8c82542d · 27 Oct 2026Report an issue or request a re-scan

• Publisheractionbook GitHub organizationOwner of the repository this skill is read from
• Source folderactionbook/rust-skills/skills/domain-embeddedThe exact folder we audited
• LicenceNot declaredAs the repository states it
• Commit pinned for this verdictf4ff8c82542dA new audit runs when the source changes
• Repository statusNot archivedLast push 65 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Use when developing embedded/no_std Rust. Keywords: embedded, no_std, microcontroller, MCU, ARM, RISC-V, bare metal, firmware, HAL, PAC, RTIC, embassy, interrupt, DMA, peripheral, GPIO, SPI, I2C, UART, embedded-hal,…

---
name: domain-embedded
description: "Use when developing embedded/no_std Rust. Keywords: embedded, no_std, microcontroller, MCU, ARM, RISC-V, bare metal, firmware, HAL, PAC, RTIC, embassy, interrupt, DMA, peripheral, GPIO, SPI, I2C, UART, embedded-hal, cortex-m, esp32, stm32, nrf, 嵌入式, 单片机, 固件, 裸机"
globs: ["**/Cargo.toml", "**/.cargo/config.toml"]
user-invocable: false
---

## Project Context (Auto-Injected)

**Target configuration:**
!`cat .cargo/config.toml 2>/dev/null || echo "No .cargo/config.toml found"`

---

# Embedded Domain

> **Layer 3: Domain Constraints**

## Domain Constraints → Design Implications

| Domain Rule | Design Constraint | Rust Implication |
|-------------|-------------------|------------------|
| No heap | Stack allocation | heapless, no Box/Vec |
| No std | Core only | #![no_std] |
| Real-time | Predictable timing | No dynamic alloc |
| Resource limited | Minimal memory | Static buffers |
| Hardware safety | Safe peripheral access | HAL + ownership |
| Interrupt safe | No blocking in ISR | Atomic, critical sections |

---

## Critical Constraints

### No Dynamic Allocation

```
RULE: Cannot use heap (no allocator)
WHY: Deterministic memory, no OOM
RUST: heapless::Vec<T, N>, arrays
```

### Interrupt Safety

```
RULE: Shared state must be interrupt-safe
WHY: ISR can preempt at any time
RUST: Mutex<RefCell<T>> + critical section
```

### Hardware Ownership

```
RULE: Peripherals must have clear ownership
WHY: Prevent conflicting access
RUST: HAL takes ownership, singletons
```

---

## Trace Down ↓

From constraints to design (Layer 2):

```
"Need no_std compatible data structures"
    ↓ m02-resource: heapless collections
    ↓ Static sizing: heapless::Vec<T, N>

"Need interrupt-safe state"
    ↓ m03-mutability: Mutex<RefCell<Option<T>>>
    ↓ m07-concurrency: Critical sections

"Need peripheral ownership"
    ↓ m01-ownership: Singleton pattern
    ↓ m12-lifecycle: RAII for hardware
```

---

## Layer Stack

| Layer | Examples | Purpose |
|-------|----------|---------|
| PAC | stm32f4, esp32c3 | Register access |
| HAL | stm32f4xx-hal | Hardware abstraction |
| Framework | RTIC, Embassy | Concurrency |
| Traits | embedded-hal | Portable drivers |

## Framework Comparison

| Framework | Style | Best For |
|-----------|-------|----------|
| RTIC | Priority-based | Interrupt-driven apps |
| Embassy | Async | Complex state machines |
| Bare metal | Manual | Simple apps |

## Key Crates

| Purpose | Crate |
|---------|-------|
| Runtime (ARM) | cortex-m-rt |
| Panic handler | panic-halt, panic-probe |
| Collections | heapless |
| HAL traits | embedded-hal |
| Logging | defmt |
| Flash/debug | probe-run |

## Design Patterns

| Pattern | Purpose | Implementation |
|---------|---------|----------------|
| no_std setup | Bare metal | `#![no_std]` + `#![no_main]` |
| Entry point | Startup | `#[entry]` or embassy |
| Static state | ISR access | `Mutex<RefCell<Option<T>>>` |
| Fixed buffers | No heap | `heapless::Vec<T, N>` |

## Code Pattern: Static Peripheral

```rust
#![no_std]
#![no_main]

use cortex_m::interrupt::{self, Mutex};
use core::cell::RefCell;

static LED: Mutex<RefCell<Option<Led>>> = Mutex::new(RefCell::new(None));

#[entry]
fn main() -> ! {
    let dp = pac::Peripherals::take().unwrap();
    let led = Led::new(dp.GPIOA);

    interrupt::free(|cs| {
        LED.borrow(cs).replace(Some(led));
    });

    loop {
        interrupt::free(|cs| {
            if let Some(led) = LED.borrow(cs).borrow_mut().as_mut() {
                led.toggle();
            }
        });
    }
}
```

---

## Common Mistakes

| Mistake | Domain Violation | Fix |
|---------|-----------------|-----|
| Using Vec | Heap allocation | heapless::Vec |
| No critical section | Race with ISR | Mutex + interrupt::free |
| Blocking in ISR | Missed interrupts | Defer to main loop |
| Unsafe peripheral | Hardware conflict | HAL ownership |

---

## Trace to Layer 1

| Constraint | Layer 2 Pattern | Layer 1 Implementation |
|------------|-----------------|------------------------|
| No heap | Static collections | heapless::Vec<T, N> |
| ISR safety | Critical sections | Mutex<RefCell<T>> |
| Hardware ownership | Singleton | take().unwrap() |
| no_std | Core-only | #![no_std], #![no_main] |

---

## Related Skills

| When | See |
|------|-----|
| Static memory | m02-resource |
| Interior mutability | m03-mutability |
| Interrupt patterns | m07-concurrency |
| Unsafe for hardware | unsafe-checker |

Excerpt, first 4,472 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/actionbook/rust-skills
git -C rust-skills checkout f4ff8c82542d

Works in

1. 2026-10-27
   ✓SAFE B 89 / 100

   first audit · source f4ff8c82542d

Questions about domain-embedded

• github.com/actionbook/rust-skills/tree/main/skills/domain-embedd — the audited source at commit f4ff8c82542d and every finding aboveObserved · 27 Oct 2026

Spotted something wrong? Report a correction · Methodology