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 hajekim/agentic-design-patterns-skills --skill appendix-prompt-engineeringgit clone --depth 1 https://github.com/hajekim/agentic-design-patterns-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/hajekim/agentic-design-patterns-skills/appendix-prompt-engineering)<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>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 | $0.00421 | $0.03400 |
| Opus 5 | $0.00211 | $0.01700 |
| Sonnet 5 | $0.00084 | $0.00680 |
| Haiku 4.5 | $0.00042 | $0.00340 |
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.
Copies of this mod
1 near-identical copy found in the catalogue:
- appendix-prompt-engineering — 100% identical, 3 lines differ
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
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.
- 8d ago First seen · 348 lines · 421 tokens per session scan A bb00cacb8d9c
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.
Other skills, from other repositories
prompt-optimizer
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image-prompt
A Korean-language skill that turns a rough image idea into a detailed prompt for gpt-image-2, OpenAI’s image-generation model.
regex-vs-llm-structured-text
Decision framework for choosing between regex and LLM when parsing structured text — start with regex, add LLM only for low-confidence edge cases.
foundation-models-on-device
Apple FoundationModels framework for on-device LLM — text generation, guided generation with @Generable, tool calling, and snapshot streaming in iOS 26+.
seedance-antislop
Detect and remove hollow AI filler language, empty superlatives, and vague boosters that degrade Seedance 2.0 prompt quality. Use when a prompt feels generic, over-written, or 'AI-sounding', or when generation output looks bland and needs a quality pass.