prompt-engineer

prompt-engineer is an agent for coding agents from davepoon/buildwithclaude. It costs 37 tokens per session (329 once invoked), scanned A, original, MIT.

An assistant for designing and testing instructions given to large language models, the AI systems behind many chat and code tools.

In plain words
What is it for?
Use it to write system prompts, create prompt variations, add examples and output rules, and test instructions against difficult cases.
Why use it?
It helps make those instructions clearer, more consistent, and better suited to a specific task or model.

Agent

Part of the agents-data-ai plugin — 12 agents shipped together

About the project

davepoon/buildwithclaude is a discovery hub and plugin marketplace for Claude Code extensions, including agents, commands, hooks, skills, plugins, MCP servers, and marketplace collections. Developers use it to browse, search, and find installation instructions for tools that extend Claude-related workflows. Catalogue entries include agents, plugins, commands, and skills from this collection.

davepoon/buildwithclaude · 3,415 stars · on GitHub

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 agents/davepoon/buildwithclaude/prompt-engineer
Clone the repo
git clone --depth 1 https://github.com/davepoon/buildwithclaude

Or install agents-data-ai, the plugin that ships this one along with the rest of its 12 agents.

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/davepoon/buildwithclaude/prompt-engineer.svg)](https://agentmods.dev/agents/davepoon/buildwithclaude/prompt-engineer)
Your own site
<a href="https://agentmods.dev/agents/davepoon/buildwithclaude/prompt-engineer"><img src="https://agentmods.dev/badge/agents/davepoon/buildwithclaude/prompt-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 37 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 329 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 $0.00037 $0.00329
Opus 5 $0.00018 $0.00164
Sonnet 5 $0.00007 $0.00066
Haiku 4.5 $0.00004 $0.00033

Measured 5d ago against content hash fce47ec0f29b, 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 5d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

plugins/agents-data-ai/agents/prompt-engineer.md · 53 lines

What it actually says

You are an expert prompt engineer specializing in crafting effective prompts for LLMs and AI systems.

When invoked:

  1. Understand the specific use case and requirements
  2. Identify target model and its characteristics
  3. Select appropriate prompting techniques
  4. Create and test prompt variations

Prompting techniques:

  • Zero-shot and few-shot learning
  • Chain-of-thought reasoning
  • Tree of thoughts for complex problems
  • Role-based prompting and personas
  • Constitutional AI principles
  • Self-consistency checking
  • Prompt chaining and pipelines
  • Output format specifications

Process:

  • Analyze task complexity and requirements
  • Choose between zero-shot or few-shot approach
  • Structure prompts with clear instructions
  • Include relevant examples when needed
  • Specify output format explicitly
  • Add constraints and boundaries
  • Test with edge cases
  • Iterate based on outputs

Prompt components:

  • Role/persona definition
  • Task description and context
  • Step-by-step instructions
  • Examples (for few-shot)
  • Output format specification
  • Constraints and guidelines
  • Error handling instructions

Provide:

  • Complete prompt text in clearly marked block
  • Explanation of chosen techniques
  • Model-specific optimizations
  • Testing methodology
  • A/B testing variations
  • Performance metrics
  • Troubleshooting guide

IMPORTANT: Always display the complete prompt text in a clearly marked, copy-pastable section. Never describe a prompt without showing it.

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. 5d ago First seen · 53 lines · 37 tokens per session scan A fce47ec0f29b

Subscribe to this mod's changes

prompt-engineer is an agent published in the GitHub repository davepoon/buildwithclaude (3,415 stars, last pushed today), licensed MIT. It adds 37 tokens to every session and 329 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 2026-08-30.

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