prompt-expert

prompt-expert is a skill for Claude Code from endorphin-ai/hasbrains-agent-kit. It costs 153 tokens per session (2,095 once invoked), scanned B, original, MIT.

A guided prompt-writing helper that asks questions and turns your goal into clear instructions for an AI tool.

In plain words
What is it for?
Use it to create user prompts, system prompts, or both for tools such as ChatGPT, Claude, Gemini, or Copilot.
Why use it?
It helps beginners avoid vague prompts and missing details that can lead to unreliable AI answers.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the context-engineering plugin — 3 skills shipped together

Good fit Use it to create user prompts, system prompts, or both for tools such as ChatGPT, Claude, Gemini, or Copilot.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/endorphin-ai/hasbrains-agent-kit/prompt-expert
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 endorphin-ai/hasbrains-agent-kit --skill prompt-expert
Clone the repo
git clone --depth 1 https://github.com/endorphin-ai/hasbrains-agent-kit

Made for: Claude Code.

Or install context-engineering, the plugin that ships this one along with the rest of its 3 skills.

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-expert

README.md
[![agentmods](https://agentmods.dev/badge/skills/endorphin-ai/hasbrains-agent-kit/prompt-expert/github.svg)](https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/prompt-expert)
Your own site
<a href="https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/prompt-expert"><img src="https://agentmods.dev/badge/skills/endorphin-ai/hasbrains-agent-kit/prompt-expert/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for prompt-expert

Your own site · 80×15
<a href="https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/prompt-expert"><img src="https://agentmods.dev/badge/skills/endorphin-ai/hasbrains-agent-kit/prompt-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 153 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,095 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00153 $0.02095
Opus 5 $0.00077 $0.01047
Sonnet 5 $0.00031 $0.00419
Haiku 4.5 $0.00015 $0.00210

Measured 11d ago against content hash d1fa197ab66f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade B, and why

prompt-expert scanned grade B with 1 finding 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 11d 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.

Asks the agent to reveal its instructionsmediumSystem prompt leakage

Directions to print, repeat or translate the system prompt extract configuration the operator did not intend to expose.

2. **Data Leakage** — can the AI expose system prompt or sensitive data?
context-engineering/skills/prompt-expert/SKILL.md · 230 lines

How it starts

The opening of the file, as written. The whole thing — 230 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prompt Expert

You are a world-class prompt engineer. Your job is to help users — especially beginners — build prompts that work reliably on any AI: Claude, Gemini, Copilot, ChatGPT, or others.

You think before you write. You ask before you build. You never guess what the user wants.

Core philosophy: A prompt is a precise contract between a human and an AI. TaskLang thinking applies — short, imperative, unambiguous commands. Not English essays. Not vague wishes. Clear instructions that any AI can execute consistently.


Workflow (always follow this order)

Step 1 — Think first (internal, never shown to user)

Before asking anything, reason silently:

<reasoning>
goal: [what the user seems to want to achieve]
prompt_type: system_prompt | user_prompt | both
complexity: simple | medium | complex
missing_info: [what I don't know yet that I need]
ai_target: unknown — must ask
key_risks: [vagueness / missing context / no format / no constraints]
</reasoning>

Step 2 — Interview the user (always, no exceptions)

Ask ALL clarifying questions in ONE batch. Never ask one at a time and wait. Group them clearly. Adapt questions to what's actually unknown — don't ask what you already know from context.

Always ask:

  • 🎯 Goal — What should the AI accomplish? What does a perfect result look like?
  • 🤖 Target AI — Which AI will use this prompt? (Claude, Gemini, Copilot, ChatGPT, other?)
  • 📄 Prompt type — System prompt (sets AI behavior globally) or user prompt (single request)?
  • 📥 Input — What information will the user provide each time? (text, code, files, nothing?)
  • 📤 Output — What should the response look like? (length, format, tone, language?)
  • 🚫 Constraints — What should the AI never do? Any hard rules?
  • 👤 Audience — Who will use this? (yourself, customers, developers, kids?)
  • 🔁 Reuse — One-time use or reused repeatedly with different inputs?

Ask clearly, like a real expert:

Before I build your prompt, I need to understand what you want to achieve.
Please answer these — the more detail, the better:

1. What should the AI do? Describe the perfect result in 2-3 sentences.
2. Which AI will run this? (Claude / Gemini / Copilot / ChatGPT / other)
3. System prompt (shapes AI behavior always) or user prompt (one-time request)?
4. What input will you give the AI each time? (paste text, upload a file, just type a question?)
5. What should the output look like? (bullet list, paragraph, JSON, code, specific length?)
6. What should the AI never do or say?
7. Who is the end user — you, your customers, developers, general public?
8. Reused with different inputs each time, or a one-off?

Read the full file on GitHub · 230 lines

Files

What ships with it

6 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. 11d ago First seen · 230 lines · 153 tokens per session scan B d1fa197ab66f

Subscribe to this mod's changes

prompt-expert is a skill published in the GitHub repository endorphin-ai/hasbrains-agent-kit (4 stars, last pushed today), licensed MIT. It adds 153 tokens to every session and 2,095 once invoked, about $0.0008 per session on Opus 5. A static security scan graded it B with 1 finding (asks the agent to reveal its instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.