battle-tested-engineer

battle-tested-engineer is a cursor rule for Cursor from sayeed1999/agent-skills. It costs 1,088 tokens per session, scanned A, original, MIT.

A set of rules for making careful, simple changes to code, refactoring, tests, and frontend interfaces. It also requires short, plain explanations during coding work.

In plain words
What is it for?
Use it to guide implementation, code reviews, refactors, test work, technical decisions, and frontend changes.
Why use it?
It helps prevent unnecessary abstractions, oversized changes, broken existing behavior, and explanations that are harder to follow than the code.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

Good fit Use it to guide implementation, code reviews, refactors, test work, technical decisions, and frontend changes.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/sayeed1999/agent-skills/battle-tested-engineer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Clone the repo
git clone --depth 1 https://github.com/sayeed1999/agent-skills

Made for: Cursor.

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.

agentmods badge for battle-tested-engineer

README.md
[![agentmods](https://agentmods.dev/badge/rules/sayeed1999/agent-skills/battle-tested-engineer.svg)](https://agentmods.dev/rules/sayeed1999/agent-skills/battle-tested-engineer)
Your own site
<a href="https://agentmods.dev/rules/sayeed1999/agent-skills/battle-tested-engineer"><img src="https://agentmods.dev/badge/rules/sayeed1999/agent-skills/battle-tested-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 1,088 This file is loaded in full into every session.
When invoked 1,088 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.01088 $0.01088
Opus 5 $0.00544 $0.00544
Sonnet 5 $0.00218 $0.00218
Haiku 4.5 $0.00109 $0.00109

Measured 7d ago against content hash d5d2ea5f6604, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

battle-tested-engineer 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 7d ago.

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.

.cursor/rules/battle-tested-engineer.mdc · 102 lines

How it starts

The opening of the file, as written. The whole thing — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Battle Tested Engineer

Goal: least code, fix problem, no break working stuff.

Output style

  • Explain in simple terms like a human.
  • Write specs as if any engineer would easily catch. Every spec/adr/decision doc/explanation/answer should be simple, easy to understand for human engineers with no over-complication, no unnecessary details, no repeated redundant explanation in multiple blocks.
  • Document core business workflows, decisions, algorithms, approaches.
  • No extra explanation than asked.
  • No decorative tables, emoji, tool narration. Errors: quote shortest relevant line only.

1. Think before code

  • State assumption, no guess.
  • Multi interpretation → show all, no pick.
  • Unclear ask → stop, name confusion, ask.
  • Simpler way exist → say it.

2. Simplicity

  • Senior-line estimate; actual >4x → cut.
  • No unrequested feature/flexibility/config/error-handling for impossible case.
  • Prefer stdlib/dep over hand-roll.
  • Function many unrelated thing → split single-responsibility. Already one thing → leave.
  • YAGNI/DRY/SOLID when shape need — not checklist.
  • Comment why, not what.
  • Red flag: single-use abstraction, one-method "manager", options object one caller.

3. Architecture boundaries (Clean Architecture)

  • Business rules are the center. Code depends inward, never outward.
  • Frameworks are tools, not foundations. UI, ORM, web framework, database are replaceable details.
  • Controllers thin: translate input/output only. No business decisions.
  • Use cases focused: one use case = one application action.
  • Domain models clean: no database, HTTP, framework, or infrastructure knowledge inside.
  • Business behavior near business data. Do not scatter rules across controllers/services/helpers.
  • Interfaces at real boundaries: external systems, storage, APIs, queues. No fake abstraction.
  • Dependencies explicit. Avoid hidden globals, magic imports, service locators, or implicit coupling.
  • Composition over inheritance. Assemble behavior instead of deep class trees.
  • Organize around business capabilities, not technical layers.
Bad:    controllers/ services/ repositories/
Better: orders/ payments/ users/
  • Design for change. Protect stable business rules from changing technology.
  • Dependency direction matters more than folder structure.
  • If removing a framework requires rewriting business logic, the boundary is wrong.

Read the full file on GitHub · 102 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.

  1. 7d ago First seen · 102 lines · 1,088 tokens per session scan A d5d2ea5f6604

Subscribe to this mod's changes

battle-tested-engineer is a cursor rule published in the GitHub repository sayeed1999/agent-skills (6 stars, last pushed 7d ago), licensed MIT. It adds 1,088 tokens to every session, about $0.0054 per session on Opus 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 2026-08-31.

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