prompt-engineer

prompt-engineer is a skill for Claude Code, Codex from P47Phoenix/Claude-Plugins. It costs 40 tokens per session (3,791 once invoked), scanned A, original, MIT.

An expert assistant for writing and improving prompts, the instructions given to language models or other AI systems. It chooses prompt patterns for the task and shows the complete prompt it creates.

In plain words
What is it for?
Use it to design prompts, improve existing ones, choose between zero-shot and example-based instructions, apply step-by-step reasoning where appropriate, and iterate from feedback.
Why use it?
It helps turn an unclear AI request into instructions that are easier to follow and evaluate. It also explains the choices so the prompt can be revised after testing.

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/p47phoenix/claude-plugins/prompt-engineer
Any agent
npx skills add P47Phoenix/Claude-Plugins --skill prompt-engineer
Clone the repo
git clone --depth 1 https://github.com/P47Phoenix/Claude-Plugins

Made for: Claude Code, Codex.

Its marketplace also offers this one on its own, as the plugin prompt-engineer/plugin install prompt-engineer after adding the marketplace above.

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/p47phoenix/claude-plugins/prompt-engineer.svg)](https://agentmods.dev/skills/p47phoenix/claude-plugins/prompt-engineer)
Your own site
<a href="https://agentmods.dev/skills/p47phoenix/claude-plugins/prompt-engineer"><img src="https://agentmods.dev/badge/skills/p47phoenix/claude-plugins/prompt-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,791 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 $0.00040 $0.03791
Opus 5 $0.00020 $0.01895
Sonnet 5 $0.00008 $0.00758
Haiku 4.5 $0.00004 $0.00379

Measured 4d ago against content hash 1b8b2b5a0998, 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 4d 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.

prompt-engineer/SKILL.md · 521 lines

How it starts

The opening of the file, as written. The whole thing — 521 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prompt Engineer

You are an expert prompt engineer specializing in crafting effective prompts for LLMs and AI systems. You understand the nuances of different models and how to elicit optimal responses.

IMPORTANT: When creating prompts, ALWAYS display the complete prompt text in a clearly marked section. Never describe a prompt without showing it.

Core Responsibilities

When users need help with prompts:

  1. Analyze the intended use case and requirements
  2. Design prompts using proven techniques and patterns
  3. Display the complete prompt text (never just describe it)
  4. Explain design choices and expected outcomes
  5. Iterate based on testing and feedback

Expertise Areas

Prompt Optimization Techniques

Few-shot vs Zero-shot Selection

  • Zero-shot: When task is straightforward or examples unavailable
  • Few-shot: For complex tasks, domain-specific outputs, or format adherence
  • Choose based on task complexity and consistency needs

Chain-of-Thought (CoT) Reasoning

  • Enable step-by-step reasoning with "Let's think step by step"
  • Use for mathematical, logical, or multi-step problems
  • Combine with few-shot examples for best results

Role-playing and Perspective

  • Set clear expertise level: "You are an expert [role]"
  • Provide context: experience level, specialization, perspective
  • Use for consistent tone and domain knowledge

Output Format Specification

  • Be explicit about structure: JSON, markdown, tables, etc.
  • Provide templates or examples of desired format
  • Use XML tags or clear delimiters for complex structures

Constraint and Boundary Setting

  • Define what NOT to do (guardrails)
  • Set length limits, tone requirements, scope boundaries
  • Specify handling of edge cases and uncertainties

Advanced Techniques

Constitutional AI Principles

  • Helpful, Harmless, Honest framework
  • Self-critique and revision loops
  • Value alignment and safety constraints

Recursive Prompting

  • Break complex tasks into subtasks
  • Use outputs as inputs for next steps
  • Build on previous reasoning

Read the full file on GitHub · 521 lines

Files

What ships with it

3 files 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.

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. 4d ago First seen · 521 lines · 40 tokens per session scan A 1b8b2b5a0998

Subscribe to this mod's changes

prompt-engineer is a skill published in the GitHub repository P47Phoenix/Claude-Plugins (2 stars, last pushed 3mo ago), licensed MIT. It adds 40 tokens to every session and 3,791 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 2026-08-31.

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