Battle Tested Engineer
Instructions for your AI coding agent — not a library you import or an app you run.
This repo teaches your AI agent how to write and review code: ask before guessing, change only what was asked, prefer simple fixes over big refactors, and ship a working minimal version first.
Supported by Claude, Cursor, Codex, Gemini and 15+ AI agents.
This work was shaped by knowledge from two earlier skill repositories: andrej-karpathy-skills and caveman.
Quick Start Guide
- Clone this repo:
git clone https://github.com/sayeed1999/agent-skills.git
cd agent-skills
- Copy the skill into your agent skills dir:
User-wide:
mkdir -p ~/.agents/skills
cp -r skills/battle-tested-engineer ~/.agents/skills/
Project-scoped:
mkdir -p .agents/skills
cp -r skills/battle-tested-engineer .agents/skills/
- In your AI agent, try a real prompt — e.g.,
/battle-tested-engineer explain the codebase
That's it!
What it does
Nine principles for writing, reviewing, and refactoring code — plus an ultra-terse "caveman" communication style during code work (code, commits, and PR descriptions stay normal prose).
| Principle | Addresses |
|---|
| Think before code | Wrong assumptions, hidden confusion |
| Simplicity | Over-engineering, speculative abstractions |
| Surgical change | Drive-by refactors, orthogonal edits |
| Data vs UI | Components owning data, scattered loading state |
| Goal-driven execution | Vague tasks without verifiable success criteria |
| Tests | Bloated test suites, testing internals |
| Propose spec when need | Ambiguous requirements, wide blast radius |
| Ship then improve | Premature optimization, big-bang refactors |
| Gut-check before output | Silent over-build, under-delivered quality |
Install
| Tool | Method | Recommended? |
|---|
| Any agent | Copy skills/battle-tested-engineer/ to ~/.agents/skills/ or .agents/skills/ | Yes (on-demand) |
| Cursor | Copy skills/battle-tested-engineer/ to ~/.cursor/skills/ | Yes (on-demand) |
| Cursor | Copy .cursor/rules/battle-tested-engineer.mdc to project .cursor/rules/ | Optional (always-on) |
| Claude Code | Plugin marketplace (see below) | Yes (global) |
| Claude Code | curl CLAUDE.md into project root | Per-project |
| Codex | Copy skill to ~/.codex/skills/ or .agents/skills/ | Yes (on-demand) |
| Codex | curl AGENTS.md into project root | Per-project |
Generic — .agents (any agent)
User-wide:
mkdir -p ~/.agents/skills
cp -r skills/battle-tested-engineer ~/.agents/skills/
Project-scoped:
mkdir -p .agents/skills
cp -r skills/battle-tested-engineer .agents/skills/
Claude Code — Plugin (recommended)
From within Claude Code, add the marketplace:
/plugin marketplace add sayeed1999/agent-skills
Then install:
/plugin install agent-skills@agent-skills
Claude Code — Per-project CLAUDE.md
New project:
curl -o CLAUDE.md https://raw.githubusercontent.com/sayeed1999/agent-skills/main/CLAUDE.md
Existing project (append):
echo "" >> CLAUDE.md
curl https://raw.githubusercontent.com/sayeed1999/agent-skills/main/CLAUDE.md >> CLAUDE.md
Cursor — On-demand skill (recommended)
cp -r skills/battle-tested-engineer ~/.cursor/skills/
See CURSOR.md for always-apply rule setup and tradeoffs.
Codex — On-demand skill (recommended)
Global:
cp -r skills/battle-tested-engineer ~/.codex/skills/
Repo-scoped:
mkdir -p .agents/skills
cp -r skills/battle-tested-engineer .agents/skills/
See CODEX.md for AGENTS.md per-project install.
How to use it
After install, you do not invoke the skill manually. Just open a project and talk to your agent as usual.
- Install using one of the methods in Install above (pick your tool; on-demand skill is recommended).
- Open a codebase in Cursor, Claude Code, or Codex.
- Ask for work the way you already would — e.g. "fix the login 500", "review this diff", "add tests for checkout", "refactor this component".
- Let the agent apply the guidelines — it should clarify ambiguous asks, keep diffs small, and write minimal code. See EXAMPLE.md for good vs bad behavior.
On-demand skill: loaded when the task fits (refactor, review, tests, UI). General questions may not trigger it.
Always-on rule or CLAUDE.md / AGENTS.md: guidelines apply every message in that project, including ultra-terse style during code work.
Optional: merge project-specific rules into the same files (see Customization).
How to know it's working
- Fewer unnecessary changes in diffs — only requested changes appear
- Clarifying questions come before implementation, not after mistakes
- Characterization tests before risky behavior changes
- Terse responses during code work; normal prose for commits and PRs
- Clean, minimal PRs — no drive-by refactoring
Customization
These guidelines merge with project-specific instructions. Add sections like:
## Project-Specific Guidelines
- Use TypeScript strict mode
- All API endpoints must have tests
- Follow error handling in `src/utils/errors.ts`
Tradeoff note
These guidelines bias toward caution over speed. Ultra-terse output style is opt-in via the on-demand skill; it is not forced unless you install the always-apply Cursor rule or per-project CLAUDE.md / AGENTS.md.
For trivial tasks (typo fixes, obvious one-liners), use judgment — not every change needs full rigor.
Repository structure
agent-skills/
├── .claude-plugin/ # Claude Code plugin manifests
├── .cursor/rules/ # Optional always-apply Cursor rule
├── skills/ # Canonical skill definitions
│ └── battle-tested-engineer/
│ └── SKILL.md
├── CLAUDE.md # Claude Code per-project install
├── AGENTS.md # Codex per-project install
├── CURSOR.md # Cursor setup guide
├── CODEX.md # Codex setup guide
└── EXAMPLE.md # Good vs bad agent behavior
License
MIT
