Embedded agent skills and rules

Agent workflows and optional Cursor rules for MCU firmware in C/C++. Aimed at bare-metal and RTOS work. Most focus was given to C, C++ coverage is currently lacking and will be expanded in the future.

Install them into a firmware repo so the agent there follows the same review, rethink, grilling, implementation, simplification, and memory procedures.

Install

Any agent that the skills CLI supports:

npx skills add iharhl/embedded-agent-skills

Pick which skills to take, and which agents to install them on. That copies each skill folder into the path that agent reads (.claude/skills/, .agents/skills/, .opencode/skills/, and so on).

Claude Code (skills only)

/plugin marketplace add iharhl/embedded-agent-skills
/plugin install embedded-agent-skills@embedded-agent-skills

Codex (skills only)

codex plugin marketplace add iharhl/embedded-agent-skills
codex plugin add embedded-agent-skills@embedded-agent-skills

Cursor

Clone or fetch this repo, then copy. Do not paste skill bodies into rules.

git clone https://github.com/iharhl/embedded-agent-skills.git
mkdir -p your-firmware/.cursor/skills <your-firmware>/.cursor/rules
cp -R embedded-agent-skills/skills/. <your-firmware>/.cursor/skills/
cp embedded-agent-skills/.cursor/rules/commenting.mdc your-firmware/.cursor/rules/

Take commenting. The c-conventions should be tailored per-project.

cp embedded-agent-skills/.cursor/rules/c-conventions.mdc <your-firmware>/.cursor/rules/

OpenCode (skills only)

Copy skills into .opencode/skills/ (project) or ~/.config/opencode/skills/ (global).

git clone https://github.com/iharhl/embedded-agent-skills.git
mkdir -p your-firmware/.opencode/skills
cp -R embedded-agent-skills/skills/. <your-firmware>/.opencode/skills/

Claude, Codex, and OpenCode ignore .cursor/rules/. Paste rule bodies into that project's AGENTS.md if you want the same constraints there.

Invocation

Skills are slash-only. Each skill sets disable-model-invocation: true. Codex also has agents/openai.yaml with allow_implicit_invocation: false.

Host	Example
Cursor	/review-embedded
Codex	$review-embedded
Claude Code	/embedded-agent-skills:review-embedded

Before judging firmware, the skills read CLAUDE.md, AGENTS.md, and .cursor/rules/ if those exist.

In Cursor, the .mdc rules apply when matching *.c / *.h files are in context. This library's own AGENTS.md is for maintaining the library, not firmware style.

Layout

skills/                  # source of truth (all agents)
  review-embedded/
  rethink-embedded/
  grilling-embedded/
  implement-embedded/
  code-simplification-embedded/
  memory-optimization-embedded/
.cursor/rules/           # Cursor rules (.mdc); optional
.claude-plugin/          # Claude Code plugin + marketplace
.codex-plugin/           # Codex plugin
.agents/plugins/         # Codex marketplace

What is here

Rules

• commenting. Portable default. /* */ on non-trivial logic. Why, not restating the next line, not leftover fix narrative. *.c / *.h.
• c-conventions. Opinionated house style. Quote includes vs compiler headers, host-test stub include order, FILENAME_H guards, ptr == 0, unsigned U.

Skills

• review-embedded. Read-only review of a firmware diff. Sanity, defects, ISR/main races, qualitative resource signals, duplication, peripheral edge cases, docs. Silicon-facing changes need the datasheet or reference manual. /review-embedded or $review-embedded.
• rethink-embedded. Step back before building. Recovers the core idea behind the code a request touches, checks whether the request makes sense, fits, and whether the existing logic is sound, weighs simpler options including not doing it, then gives one verdict. Read-only. /rethink-embedded or $rethink-embedded.
• grilling-embedded. Architecture interview before code, scoped to a named feature unless you ask for the whole product. Rounds of frontier questions with a recommended answer on each, then a decision log. /grilling-embedded or $grilling-embedded.
• implement-embedded. Implement a settled firmware plan, then a subagent (your agent's default model, or the one you name) reviews and simplifies the diff against the plan, and the agent applies the findings worth keeping. /implement-embedded or $implement-embedded.
• code-simplification-embedded. Clarify working C firmware without changing behavior, including timing, footprint, register order, and errata workarounds. /code-simplification-embedded or $code-simplification-embedded.
• memory-optimization-embedded. Profile the image with size/map/disassembly, apply safe RAM and Flash cuts on the requested feature, and propose neighboring or whole-image wins. /memory-optimization-embedded or $memory-optimization-embedded.

These are firmware-specific. For general agent workflow (how/why a subsystem works, review, verification), pstack is a good companion in Cursor (/add-plugin pstack).

Add a skill

1. Create skills/my-skill/SKILL.md with name and description frontmatter. name must match the folder.
2. Keep the body short. Put long tables in references/.
3. For slash-only skills, set disable-model-invocation: true in the frontmatter and add agents/openai.yaml with allow_implicit_invocation: false.
4. Link it from this README.

Add a rule as .cursor/rules/my-rule.mdc with description and either alwaysApply: true or globs. See AGENTS.md for the split between rules and skills.

Acknowledgements

grilling-embedded is adapted from Matt Pocock's grill-me / grilling skills.

code-simplification-embedded is adapted from Addy Osmani's code-simplification skill.

License

MIT, see LICENSE.