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.
npx skills add jamestorrevillas/dev-skills --skill prompt-engineeringgit clone --depth 1 https://github.com/jamestorrevillas/dev-skillsWrote 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/jamestorrevillas/dev-skills/prompt-engineering)<a href="https://agentmods.dev/skills/jamestorrevillas/dev-skills/prompt-engineering"><img src="https://agentmods.dev/badge/skills/jamestorrevillas/dev-skills/prompt-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/jamestorrevillas/dev-skills/prompt-engineering"><img src="https://agentmods.dev/badge/skills/jamestorrevillas/dev-skills/prompt-engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00092 | $0.01734 |
| Opus 5 | $0.00046 | $0.00867 |
| Sonnet 5 | $0.00018 | $0.00347 |
| Haiku 4.5 | $0.00009 | $0.00173 |
Grade A, and why
prompt-engineering 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 9d 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 — 230 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Prompt Engineering
Core Philosophy
A great prompt is not a magic spell — it's a specification. The more precisely you define the goal, context, constraints, and output format, the more reliably the AI performs. Think of prompting like writing a function signature: the model is the implementation, you are the interface designer.
The Golden Rule: If the output isn't what you wanted, the problem is almost always in the prompt — not the model.
Prompt Anatomy (4-Part Structure)
Every effective prompt has four components:
ROLE: Who the AI should be (expertise, perspective, voice)
GOAL: What you want done (specific, unambiguous task)
CONTEXT: Relevant background, data, constraints, examples
OUTPUT: Exact format, length, structure of the response
Example
ROLE: You are a senior TypeScript developer with expertise in React and Next.js.
GOAL: Review this component for performance issues and suggest specific improvements.
CONTEXT: This is a client component in Next.js 15 App Router.
Performance is critical — this renders on every keystroke.
[paste code here]
OUTPUT: List issues as BLOCKER / WARNING / SUGGESTION with specific fix for each.
Core Techniques
Zero-Shot
Ask directly with no examples. Works for well-understood tasks.
Write a conventional commit message for this diff: [diff]
Few-Shot
Provide 2–3 examples before the real task. Best for format-sensitive or pattern-matching tasks.
Examples:
Input: Added login form → Output: feat(auth): add login form with email/password
Input: Fixed null crash → Output: fix(api): handle null response from user endpoint
Now write a commit message for: [diff]
Chain-of-Thought (CoT)
Force step-by-step reasoning. Add "Think step by step" or "Reason through this before answering."
Is this API design RESTful? Think step by step before answering.
Role / Persona Assignment
Set expertise level and perspective upfront.
You are a security engineer specializing in OWASP Top 10.
Review this authentication code for vulnerabilities.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 9d ago First seen · 230 lines · 0 tokens per session scan A d1782932f490
prompt-engineering is a skill published in the GitHub repository jamestorrevillas/dev-skills (3 stars, last pushed 5mo ago), licensed MIT. It adds 92 tokens to every session and 1,734 once invoked, about $0.0005 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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