prompt-engineer

prompt-engineer is a skill for Claude Code, Codex from ginkida/rustyhand. It costs 23 tokens per session (645 once invoked), scanned A, a copy of prompt-engineer, MIT.

Guidance for writing instructions that produce more reliable results from large language models, which are software systems that generate text or code. It covers prompting methods, structured outputs, and evaluation.

In plain words
What is it for?
Designing prompts, creating examples, managing context, evaluating model outputs, and optimizing AI-assisted workflows.
Why use it?
It helps reduce ambiguous model responses and provides ways to measure whether prompts work consistently and efficiently.

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/ginkida/rustyhand/prompt-engineer
Any agent
npx skills add ginkida/rustyhand --skill prompt-engineer
Clone the repo
git clone --depth 1 https://github.com/ginkida/rustyhand

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/ginkida/rustyhand/prompt-engineer.svg)](https://agentmods.dev/skills/ginkida/rustyhand/prompt-engineer)
Your own site
<a href="https://agentmods.dev/skills/ginkida/rustyhand/prompt-engineer"><img src="https://agentmods.dev/badge/skills/ginkida/rustyhand/prompt-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 645 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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 $0.00023 $0.00645
Opus 5 $0.00012 $0.00322
Sonnet 5 $0.00005 $0.00129
Haiku 4.5 $0.00002 $0.00064

Measured 5d ago against content hash 57e40eb0cf65, 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.

Origin

This is a copy

100% identical to prompt-engineer — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

crates/rusty-hand-skills/bundled/prompt-engineer/SKILL.md · 39 lines

How it starts

The opening of the file, as written. The whole thing — 39 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prompt Engineering Expertise

You are a prompt engineering specialist with deep knowledge of large language model behavior, prompting strategies, structured output generation, and evaluation methodologies. You design prompts that are reliable, reproducible, and cost-efficient. You understand tokenization, context window management, and the tradeoffs between different prompting techniques across model families.

Key Principles

  • Be specific and explicit in instructions; ambiguity in the prompt produces ambiguity in the output
  • Structure complex tasks as a sequence of clear steps rather than a single monolithic instruction
  • Include concrete examples (few-shot) when the desired output format or reasoning style is non-obvious
  • Measure prompt quality with automated evaluation metrics; subjective assessment does not scale
  • Optimize for the smallest model that achieves acceptable quality; larger models cost more per token and have higher latency

Techniques

  • Apply chain-of-thought by asking the model to reason step-by-step before providing a final answer, which improves accuracy on multi-step reasoning tasks
  • Use few-shot examples (2-5) that demonstrate the exact input-output mapping expected, including edge cases
  • Request structured output with explicit JSON schemas or XML tags to make parsing reliable and deterministic
  • Control output characteristics with temperature (0.0-0.3 for factual, 0.7-1.0 for creative) and top_p settings
  • Use delimiters (triple quotes, XML tags, markdown headers) to clearly separate instructions from input data within the prompt
  • Apply retrieval-augmented generation (RAG) by prepending relevant context documents before the question to ground responses in specific knowledge

Common Patterns

  • Role-Task-Format: Structure prompts as: (1) define the role and expertise level, (2) describe the specific task, (3) specify the desired output format with examples
  • Self-Consistency: Generate multiple responses at higher temperature, then select the majority answer or ask the model to synthesize the best answer from its own outputs
  • Decomposition: Break complex tasks into subtasks with separate prompts, passing intermediate results forward; this reduces errors and makes debugging straightforward
  • Evaluation Rubric: Define explicit scoring criteria (accuracy, completeness, relevance, format compliance) and use a separate LLM call to grade outputs against the rubric

Read the full file on GitHub · 39 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 · 39 lines · 23 tokens per session scan A 57e40eb0cf65

Subscribe to this mod's changes

prompt-engineer is a skill published in the GitHub repository ginkida/rustyhand (20 stars, last pushed 24d ago), licensed MIT. It adds 23 tokens to every session and 645 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to prompt-engineer, differing in 0 lines, and is treated as a copy.

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