prompt-engineer

prompt-engineer is a skill for Claude Code, Codex from AIDotNet/MoYuCode. It costs 35 tokens per session (710 once invoked), scanned A, original, MIT.

A guide for designing, improving, and testing prompts for AI models. It covers examples, structured outputs, and methods for making instructions clearer and more consistent.

In plain words
What is it for?
Use it when creating a prompt, improving an existing one, or testing instructions for tasks such as classification or structured answers.
Why use it?
It helps reduce vague or unreliable model responses by giving prompts a defined role, process, format, and examples.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/aidotnet/moyucode/prompt-engineer
Any agent
npx skills add AIDotNet/MoYuCode --skill prompt-engineer
Clone the repo
git clone --depth 1 https://github.com/AIDotNet/MoYuCode

Made for: Claude Code, Codex.

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 prompt-engineer

README.md
[![agentmods](https://agentmods.dev/badge/skills/aidotnet/moyucode/prompt-engineer.svg)](https://agentmods.dev/skills/aidotnet/moyucode/prompt-engineer)
Your own site
<a href="https://agentmods.dev/skills/aidotnet/moyucode/prompt-engineer"><img src="https://agentmods.dev/badge/skills/aidotnet/moyucode/prompt-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 710 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00035 $0.00710
Opus 5 $0.00017 $0.00355
Sonnet 5 $0.00007 $0.00142
Haiku 4.5 $0.00003 $0.00071

Measured 5d ago against content hash 91d4fd55db31, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prompt-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 5d 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.

skills/community/prompt-engineer/SKILL.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prompt Engineer Skill

Description

Design and optimize prompts for AI models using proven techniques.

Trigger

  • /prompt command
  • User requests prompt design
  • User needs AI prompt optimization

Prompt

You are a prompt engineering expert that creates effective AI prompts.

System Prompt Template

You are a [ROLE] that [PRIMARY_FUNCTION].

## Core Responsibilities
1. [Responsibility 1]
2. [Responsibility 2]
3. [Responsibility 3]

## Guidelines
- Always [guideline 1]
- Never [guideline 2]
- When uncertain, [fallback behavior]

## Output Format
[Specify exact format expected]

## Examples
[Provide 2-3 examples of ideal responses]

Few-Shot Learning

Classify the sentiment of customer reviews.

Examples:
Review: "This product exceeded my expectations! Fast shipping too."
Sentiment: positive

Review: "Broke after one week. Complete waste of money."
Sentiment: negative

Review: "It works as described. Nothing special."
Sentiment: neutral

Now classify:
Review: "{user_input}"
Sentiment:

Chain-of-Thought

Solve this step by step:

Problem: A store has 150 apples. They sell 40% on Monday and 30 more on Tuesday. How many remain?

Let me think through this:
1. Starting amount: 150 apples
2. Monday sales: 150 × 0.40 = 60 apples sold
3. After Monday: 150 - 60 = 90 apples
4. Tuesday sales: 30 apples sold
5. After Tuesday: 90 - 30 = 60 apples

Answer: 60 apples remain

Structured Output

Extract information from the text and return as JSON.

Text: "John Smith, age 32, works as a software engineer at Google in Mountain View. He can be reached at [email protected]."

Output format:
{
  "name": "string",
  "age": number,
  "occupation": "string",
  "company": "string",
  "location": "string",
  "email": "string"
}

Response:
{
  "name": "John Smith",
  "age": 32,
  "occupation": "software engineer",
  "company": "Google",
  "location": "Mountain View",
  "email": "[email protected]"
}

Read the full file on GitHub · 132 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. 5d ago First seen · 132 lines · 35 tokens per session scan A 91d4fd55db31

Subscribe to this mod's changes

prompt-engineer is a skill published in the GitHub repository AIDotNet/MoYuCode (84 stars, last pushed 7mo ago), licensed MIT. It adds 35 tokens to every session and 710 once invoked, about $0.0002 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 2026-08-30.

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