Prompt Engineering Expert

Write, review, rewrite, and debug prompts for Claude (system prompts, custom instructions, agent and harness prompts, CLAUDE.md files, one-off task prompts), tuned to the model that will run them. Applies Anthropic's current prompting best practices (reviewed 2026-10-28), with local model-specific tuning for Claude Opus 5.5 and Claude Fable 5.1 / Mythos 5.1, per-model notes and docs lookups for Sonnet 5.5, Sonnet 5, Haiku 5.5, Opus 5, Opus 4.8, and Fable 5, and general guidance for every other model. Use this whenever the user asks to improve, optimize, tighten, fix, critique, or migrate a pro

7 starsAI, LLMs & Agents

Install

skills CLI (Claude Code, Cursor, Codex and more)

npx skills add S3LabsAI/prompt-engineering-expert --skill prompt-engineering-expert

Manual install

git clone --depth 1 https://github.com/S3LabsAI/prompt-engineering-expert.git /tmp/prompt-engineering-expert
mkdir -p ~/.claude/skills
cp -r /tmp/prompt-engineering-expert/. ~/.claude/skills/prompt-engineering-expert

Personal skills live in ~/.claude/skills. Use .claude/skills in a project folder to share a skill with your team.

From the SKILL.md

# Prompt engineering expert

Your job is to turn the user's prompt, or their description of one, into the version that works best on the model that will run it, and to explain the changes briefly enough that they can judge them.

The target model matters because prompting advice is measured per model. A rule that fixed an older model can hurt a newer one. Anti-formatting rules written for chatty models make Fable 5.1 under-format, instructions to "write out your reasoning" can be declined on Opus 5.5, Opus 5, Sonnet 5.5, and the Fable family, and verification lines that helped older models make Opus 5 over-verify. So identify the model first, then apply the matching guidance.

## Step 1. Identify the target model

Take the first of these that applies:

1. The model the user names ("for Opus 5.5," "our Fable bot").
2. A model string or config in the material (`claude-opus-5-5`, `claude-fable-5-1`, `claude-sonnet-5-5`, `model=` in code).
3. Where the prompt will run. If it's for this same environment (a Claude app Project, a skill, custom instructions, a [CLAUDE.md](http://CLAUDE.md) for this agent) and no model is named, use the model running this conversation. Your system prompt names it.
4. Still unknown. If the answer would change the rewrite (an API integration, an agent harness), ask one short question. Otherwise use the general guidance and say which model you assumed.

Then read the matching references:

| Target model | Read |
| --- | --- |

Read the full skill on GitHub

Details

Skill name: prompt-engineering-expert
Repository: S3LabsAI/prompt-engineering-expert
Repo updated: 29 October 2026

FAQ

What does the Prompt Engineering Expert skill do?

How do I install the Prompt Engineering Expert skill?

skills CLI (Claude Code, Cursor, Codex and more): npx skills add S3LabsAI/prompt-engineering-expert --skill prompt-engineering-expert. Skills go in ~/.claude/skills (personal) or .claude/skills (project), and Claude loads them automatically when a task matches the description.

Is Prompt Engineering Expert popular?

It lives in S3LabsAI/prompt-engineering-expert, which has 7 GitHub stars and 0 forks.

Related skills

Reelwright

janieehe/reelwright

面向旅拍店、妆造店、民宿，以及独立摄影师、独立妆造师等本地生活内容生产者，系统产出可直接开拍的短视频内容。覆盖拆解爆款、商家档案、客群画像、账号定位、内容矩阵、选题清单、脚本、分镜表、拍摄方案九个方向，每个方向都能单独用、也能串成一条从对标到开拍的线，台词/旁白去 AI 味、逐字可念。当创作者或自媒体人想拍短视频、起号、规划账号或选题、写脚本或改稿、拆分镜、排拍摄方案，或拆解对标视频/评论区、把爆款拍法换成自己的店（换皮）时使用。

AI, LLMs & Agents

Pelago

Mikebouskila/pelago

Make an AI coding Wrapped from local Claude Code and Codex history. Turns every project into a pixel-art island and adds a story-style recap, a coding archetype such as "The Midnight Harbormaster", relics, shareable cards and a short video reel, all in one offline HTML page. Use when the user asks for their Claude Code Wrapped, Codex Wrapped or AI coding Wrapped, a year in review or monthly recap of what they built with AI agents, their coding archetype or coding personality, a stats recap of sessions and tokens, a team recap or team Wrapped merged from several people's exports, or a way to vi

AI, LLMs & Agents

Tier 1 2 3 Skill System

H-Ali13381/tier-1-2-3-skill-system

Use when creating, editing, reviewing, packaging, or organizing AI-agent skills and deciding whether a skill should be text-only, script-backed, or backed by an ML/specialist pipeline.

AI, LLMs & Agents

Openspec Agent Sdd

trotsky1997/openspec-agent-sdd

Use when an autonomous coding agent (no human in the loop) needs to drive OpenSpec spec-driven development end-to-end — bootstrap, propose, implement, and archive a change without slash commands or interactive prompts. Triggers on "用 openspec 自主开发", "agent-own spec-driven dev", "openspec 无人值守 / 非交互", "spec-driven 自动跑一遍", "openspec init/propose/apply/archive 全自动", "drive OpenSpec from an agent". Captures the verified non-interactive CLI loop, the status/instructions state machine, the substitutions for OpenSpec's built-in "ask the user" stops, and validation-driven self-correction.

AI, LLMs & Agents

Agent Teams

AntonioGuadagnoAI/agent-teams

Playbook operativo per creare e orchestrare agent team in Claude Code (piu istanze di Claude Code che collaborano condividendo una task list e messaggiandosi tra loro). Usa questa skill ogni volta che l'utente chiede di lanciare un team di agenti, fare spawn di teammate, parallelizzare un lavoro su piu agenti, eseguire una review o un'indagine multi-agente, coordinare lavoro su frontend/backend/test con agenti separati, o menziona "agent team", "teammate", "team lead", "team di agenti" o "agenti in parallelo", anche senza nominare esplicitamente la funzione. Usala anche quando un task e abbast

AI, LLMs & Agents

Mggu

transicle/MGGU-LLM-NoCode-Prompt

Cut off AI code generation entirely, instead explain the how and why.

AI, LLMs & Agents

Browse the most popular Claude skills, all ai, llms & agents skills, or write your own with the skills generator.