appendix-prompt-engineering

appendix-prompt-engineering is a skill for Claude Code, Codex from hajekim/agentic-design-patterns-skills. It costs 421 tokens per session (3,400 once invoked), scanned A, original, MIT.

Guidance for designing and improving instructions given to language models, including structured requests and repeatable prompting methods.

In plain words
What is it for?
Use it to write or refine prompts, request JSON or other structured output, test prompt variations, and design instructions for agents.
Why use it?
It helps make model responses more consistent, complete, and correctly formatted.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to write or refine prompts, request JSON or other structured output, test prompt variations, and design instructions for agents.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/hajekim/agentic-design-patterns-skills/appendix-prompt-engineering
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.

Any agent
npx skills add hajekim/agentic-design-patterns-skills --skill appendix-prompt-engineering
Clone the repo
git clone --depth 1 https://github.com/hajekim/agentic-design-patterns-skills

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 appendix-prompt-engineering

README.md
[![agentmods](https://agentmods.dev/badge/skills/hajekim/agentic-design-patterns-skills/appendix-prompt-engineering.svg)](https://agentmods.dev/skills/hajekim/agentic-design-patterns-skills/appendix-prompt-engineering)
Your own site
<a href="https://agentmods.dev/skills/hajekim/agentic-design-patterns-skills/appendix-prompt-engineering"><img src="https://agentmods.dev/badge/skills/hajekim/agentic-design-patterns-skills/appendix-prompt-engineering.svg" alt="Measured on agentmods" height="20"></a>
Per session 421 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,400 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00421 $0.03400
Opus 5 $0.00211 $0.01700
Sonnet 5 $0.00084 $0.00680
Haiku 4.5 $0.00042 $0.00340

Measured 8d ago against content hash bb00cacb8d9c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

appendix-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 8d 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

Copies of this mod

1 near-identical copy found in the catalogue:

skills/appendix-prompt-engineering/SKILL.md · 348 lines

How it starts

The opening of the file, as written. The whole thing — 348 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Appendix A - Prompt Engineering

Overview

Prompt Engineering is the disciplined practice of crafting, iterating, and optimizing the inputs given to language models to produce reliable, high-quality outputs. It is not a simple act of asking questions — it is a structured engineering discipline that transforms a general-purpose language model into a specialized, highly capable tool for specific tasks.

For agents, prompting is the foundational layer: every agentic pattern depends on well-crafted prompts. A powerful model with a poor prompt produces poor results. A well-engineered prompt transforms model outputs from probabilistic guesses into deterministic, structured, trustworthy cognitive operations.

Core Principle: Treat prompts as code — version them, test them, iterate them, and document what works and why.

When This Skill Applies

Activate this pattern when:

  • Building any LLM-powered agent that needs reliable, structured outputs
  • Writing system prompts, user instructions, or tool descriptions for agents
  • An agent produces inconsistent, hallucinated, or poorly formatted responses
  • You need structured data (JSON, XML) from model outputs
  • Implementing Chain-of-Thought, ReAct, or few-shot reasoning patterns
  • Testing and comparing different prompt strategies
  • Preparing prompts for production deployment

Rule of thumb: Every agent interaction is a prompt. Engineer them deliberately — don't leave agent behavior to chance.

Prompting Technique Hierarchy

Zero-Shot: No examples — just instructions
    → Simple tasks with clear instructions

One-Shot: One example — demonstrate the pattern
    → When output format matters

Few-Shot: 2–5 examples — show the range
    → Complex tasks, classification, structured extraction

Chain-of-Thought: "Think step by step" + examples
    → Reasoning tasks, math, multi-step problems

ReAct: Thought → Action → Observation loop
    → Agents using tools in an iterative loop

DEFINE → PLAN → ACTION Workflow

Read the full file on GitHub · 348 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. 8d ago First seen · 348 lines · 421 tokens per session scan A bb00cacb8d9c

Subscribe to this mod's changes

appendix-prompt-engineering is a skill published in the GitHub repository hajekim/agentic-design-patterns-skills (4 stars, last pushed 5mo ago), licensed MIT. It adds 421 tokens to every session and 3,400 once invoked, about $0.0021 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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