Borrowing it
Nothing to install: this file belongs to DanielPodolsky/ownyourcode. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/DanielPodolsky/ownyourcode/main/.claude/skills/fundamentals/engineering/SKILL.mdgit clone --depth 1 https://github.com/DanielPodolsky/ownyourcodeWrote 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.
[](https://agentmods.dev/skills/danielpodolsky/ownyourcode/engineering)<a href="https://agentmods.dev/skills/danielpodolsky/ownyourcode/engineering"><img src="https://agentmods.dev/badge/skills/danielpodolsky/ownyourcode/engineering/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/danielpodolsky/ownyourcode/engineering"><img src="https://agentmods.dev/badge/skills/danielpodolsky/ownyourcode/engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00047 | $0.01373 |
| Opus 5.5 | $0.00019 | $0.00549 |
| Sonnet 5.5 | $0.00009 | $0.00275 |
| Haiku 4.5 | $0.00005 | $0.00137 |
Grade A, and why
engineering-fundamentals 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 183 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Engineering Fundamentals Review
"Code is read more than it is written. Write for the reader, not the machine."
When to Apply
Activate this skill when reviewing:
- Any code changes
- Function and variable naming
- Code organization and structure
- General refactoring decisions
Review Checklist
Naming
- Descriptive: Can you understand the variable without context?
- No abbreviations: Are names spelled out? (
usernotusr) - No generic names: No
data,temp,info,stuff? - Boolean prefix: Do booleans start with
is,has,can,should? - Function verbs: Do functions start with action verbs?
Function Design
- Single responsibility: Does each function do ONE thing?
- Size limit: Are functions under 20-30 lines?
- Parameter count: Are there fewer than 4 parameters?
- No side effects: Are pure functions actually pure?
- Early returns: Are guard clauses used instead of deep nesting?
Code Organization
- DRY: Is duplicated code extracted into functions?
- But not too DRY: Are abstractions justified (rule of three)?
- Cohesion: Are related things grouped together?
- Separation: Are unrelated things separated?
Comments & Documentation
- Why, not what: Do comments explain reasoning, not obvious code?
- No commented-out code: Is dead code deleted, not commented?
- JSDoc on public APIs: Are exported functions documented?
Common Mistakes (Anti-Patterns)
1. Magic Numbers
❌ if (status === 2) { ... }
setTimeout(callback, 86400000);
✅ const STATUS = { ACTIVE: 2, INACTIVE: 1 };
if (status === STATUS.ACTIVE) { ... }
const ONE_DAY_MS = 24 * 60 * 60 * 1000;
setTimeout(callback, ONE_DAY_MS);
2. Unclear Naming
❌ const d = new Date();
const temp = getUser();
const flag = true;
✅ const createdAt = new Date();
const currentUser = getUser();
const isAuthenticated = true;
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.
- 1mo ago First seen · 183 lines · 47 tokens per session scan A 6d2e3a8861b8
engineering-fundamentals is a skill published in the GitHub repository DanielPodolsky/ownyourcode (292 stars, last pushed 4mo ago), licensed MIT. It adds 47 tokens to every session and 1,373 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-30.
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