prompt-engineer

prompt-engineer is a skill for Claude Code from wyattowalsh/agents. It costs 48 tokens per session (5,537 once invoked), scanned A, original, MIT.

A guide to writing and improving prompts for AI models and agent tools. It covers reusable templates, examples, evaluation rubrics, context selection, and protection against untrusted instructions.

In plain words
What is it for?
Use it to craft, analyze, harden, or convert system, agent, tool, retrieval, and evaluation prompts.
Why use it?
It helps turn vague or fragile instructions into prompts that are easier to reuse, assess, and keep separate from potentially manipulative input.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter. Also seen: model in frontmatter.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is /prompt-engineer analyze ./prompts/system.md.

Part of the agents plugin — 71 skills, 20 agents, 5 hooks shipped together

Good fit Use it to craft, analyze, harden, or convert system, agent, tool, retrieval, and evaluation prompts.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/wyattowalsh/agents
agentmods
npx agentmods add skills/wyattowalsh/agents/prompt-engineer

Made for: Claude Code.

Or install agents, the plugin that ships this one along with the rest of its 71 skills, 20 agents, 5 hooks.

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/wyattowalsh/agents/prompt-engineer/github.svg)](https://agentmods.dev/skills/wyattowalsh/agents/prompt-engineer)
Your own site
<a href="https://agentmods.dev/skills/wyattowalsh/agents/prompt-engineer"><img src="https://agentmods.dev/badge/skills/wyattowalsh/agents/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/skills/wyattowalsh/agents/prompt-engineer"><img src="https://agentmods.dev/badge/skills/wyattowalsh/agents/prompt-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,537 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 9
    Skill selects an external model or provider that may use a different account or billing plan than the operator expects. Undisclosed model switches can cause unexpected cost or quota consumption.
    Fix: Remove the model/provider override or disclose it prominently and require explicit operator approval before invoking an external coding CLI or billed model.
How audits are shown
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 $0.00048 $0.05537
Opus 5.5 $0.00019 $0.02215
Sonnet 5.5 $0.00010 $0.01107
Haiku 4.5 $0.00005 $0.00554

Measured 1mo ago against content hash e65d3b10979d, 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.

The scan reads SKILL.md. This mod also ships 9 executable files (scripts/asset_toolkit/__init__.py, scripts/asset_toolkit/_shared.py, scripts/asset_toolkit/common.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/prompt-engineer/SKILL.md · 387 lines

How it starts

The opening of the file, as written. The whole thing — 387 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prompt Engineer

Comprehensive prompt and context engineering. Every non-obvious recommendation must be evidence-scoped.

Canonical Vocabulary

Use these terms exactly throughout all modes:

Term Definition
system prompt The top-level instruction block sent before user messages; sets model behavior
context window The full token budget: system prompt + conversation history + tool results + retrieved docs
context engineering Designing the entire context window, not just the prompt text — write, select, compress, isolate
template A reusable prompt structure with variable slots ({{input}}, named placeholders, or runtime arguments)
rubric A scoring framework with dimensions, levels (1-5), and concrete examples per level
few-shot example An input/output pair included in the prompt to demonstrate desired behavior
chain-of-thought (CoT) Explicit step-by-step reasoning scaffolding; beneficial for instruction-following models, harmful for reasoning models
model class Either "instruction-following" or "reasoning" — determines which techniques apply
injection Untrusted input that manipulates model behavior outside intended boundaries
anti-pattern A prompt construction that reliably degrades output quality
over-specification Adding constraints past the point where they help; too much specificity can degrade output quality and flexibility
scorecard The 5-dimension diagnostic (Clarity, Completeness, Efficiency, Robustness, Model Fit) scored 1-5
playbook Model-family-specific guidance document in references/model-playbooks.md
prefix caching Cost optimization by placing static content early so API providers cache the prefix
trust boundary The separation between trusted instructions and untrusted user, tool, retrieved, or external content
evidence class Source type behind a recommendation: official docs, peer-reviewed/preprint, community heuristic, local practice, or single-study
PromptOps Versioning, evals, rollout checks, observability, and rollback discipline for prompts in production

Read the full file on GitHub · 387 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 · 387 lines · 48 tokens per session scan A e65d3b10979d

Subscribe to this mod's changes

prompt-engineer is a skill published in the GitHub repository wyattowalsh/agents (5 stars, last pushed 1mo ago), licensed MIT. It adds 48 tokens to every session and 5,537 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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