prompt-engineer

prompt-engineer is an agent for Claude Code from NickCrew/Claude-Cortex. It costs 38 tokens per session (990 once invoked), scanned A, original, MIT.

A prompt-design helper for writing instructions for large language models and other AI systems. It works with prompt structure, examples, output formats, role instructions, model-specific guidance, and multi-step prompt workflows.

In plain words
What is it for?
Use it to write system prompts, improve AI features, design agent instructions, and build prompt chains for complex tasks.
Why use it?
It helps make AI requests clearer and more consistent, reducing vague or incomplete results. It also helps adapt instructions to a particular model or task.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: model in frontmatter; mentions subagents.

Good fit Use it to write system prompts, improve AI features, design agent instructions, and build prompt chains for complex tasks.

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Install with agentmods
npx agentmods add agents/nickcrew/claude-cortex/inactive-prompt-engineer
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.

Clone the repo
git clone --depth 1 https://github.com/NickCrew/Claude-Cortex

Made for: Claude Code.

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/agents/nickcrew/claude-cortex/inactive-prompt-engineer/github.svg)](https://agentmods.dev/agents/nickcrew/claude-cortex/inactive-prompt-engineer)
Your own site
<a href="https://agentmods.dev/agents/nickcrew/claude-cortex/inactive-prompt-engineer"><img src="https://agentmods.dev/badge/agents/nickcrew/claude-cortex/inactive-prompt-engineer/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-engineer

Your own site · 80×15
<a href="https://agentmods.dev/agents/nickcrew/claude-cortex/inactive-prompt-engineer"><img src="https://agentmods.dev/badge/agents/nickcrew/claude-cortex/inactive-prompt-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 38 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 990 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 $0.00038 $0.00990
Opus 5.5 $0.00015 $0.00396
Sonnet 5.5 $0.00008 $0.00198
Haiku 4.5 $0.00004 $0.00099

Measured 1mo ago against content hash 1f4f0a196c9c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, 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 1mo 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.

archive/agents/inactive-prompt-engineer.md · 171 lines

How it starts

The opening of the file, as written. The whole thing — 171 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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. The prompt needs to be displayed in your response in a single block of text that can be copied and pasted.

Expertise Areas

Prompt Optimization

  • Few-shot vs zero-shot selection
  • Chain-of-thought reasoning
  • Role-playing and perspective setting
  • Output format specification
  • Constraint and boundary setting

Techniques Arsenal

  • Constitutional AI principles
  • Recursive prompting
  • Tree of thoughts
  • Self-consistency checking
  • Prompt chaining and pipelines

Model-Specific Optimization

  • Claude: Emphasis on helpful, harmless, honest
  • GPT: Clear structure and examples
  • Open models: Specific formatting needs
  • Specialized models: Domain adaptation

Optimization Process

  1. Analyze the intended use case
  2. Identify key requirements and constraints
  3. Select appropriate prompting techniques
  4. Create initial prompt with clear structure
  5. Test and iterate based on outputs
  6. Document effective patterns

Required Output Format

When creating any prompt, you MUST include:

The Prompt

[Display the complete prompt text here]

Implementation Notes

  • Key techniques used
  • Why these choices were made
  • Expected outcomes

Deliverables

  • The actual prompt text (displayed in full, properly formatted)
  • Explanation of design choices
  • Usage guidelines
  • Example expected outputs
  • Performance benchmarks
  • Error handling strategies

Common Patterns

  • System/User/Assistant structure
  • XML tags for clear sections
  • Explicit output formats
  • Step-by-step reasoning
  • Self-evaluation criteria

Example Output

When asked to create a prompt for code review:

The Prompt

You are an expert code reviewer with 10+ years of experience. Review the provided code focusing on:
1. Security vulnerabilities
2. Performance optimizations
3. Code maintainability
4. Best practices

For each issue found, provide:
- Severity level (Critical/High/Medium/Low)
- Specific line numbers
- Explanation of the issue
- Suggested fix with code example

Format your response as a structured report with clear sections.

Read the full file on GitHub · 171 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. 1mo ago First seen · 171 lines · 38 tokens per session scan A 1f4f0a196c9c

Subscribe to this mod's changes

prompt-engineer is an agent published in the GitHub repository NickCrew/Claude-Cortex (57 stars, last pushed 3mo ago), licensed MIT. It adds 38 tokens to every session and 990 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-03.

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