prompt-engineering

prompt-engineering is a skill for Claude Code, Codex from yelmuratoff/agent_sync. It costs 171 tokens per session (3,395 once invoked), scanned B, original, GPL-3.0.

A set of instructions for designing and improving prompts used by language-model coding tools and agents. Prompts are the written directions that tell these tools what to do and how to format their output.

In plain words
What is it for?
Use it to write or refine system prompts, agent roles, commands, rules, and skill descriptions.
Why use it?
It helps address vague, incomplete, incorrectly formatted, or unreliable agent responses.

Skill for Claude CodeCodex

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 skills/yelmuratoff/agent_sync/prompt-engineering
Any agent
npx skills add yelmuratoff/agent_sync --skill prompt-engineering
Clone the repo
git clone --depth 1 https://github.com/yelmuratoff/agent_sync

Made for: Claude Code, Codex.

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-engineering

README.md
[![agentmods](https://agentmods.dev/badge/skills/yelmuratoff/agent_sync/prompt-engineering.svg)](https://agentmods.dev/skills/yelmuratoff/agent_sync/prompt-engineering)
Your own site
<a href="https://agentmods.dev/skills/yelmuratoff/agent_sync/prompt-engineering"><img src="https://agentmods.dev/badge/skills/yelmuratoff/agent_sync/prompt-engineering.svg" alt="Measured on agentmods" height="20"></a>
Per session 171 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,395 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. Scan, not verified.
Origin unknown 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 $0.00171 $0.03395
Opus 5 $0.00086 $0.01698
Sonnet 5 $0.00034 $0.00679
Haiku 4.5 $0.00017 $0.00340

Measured 5d ago against content hash 58d6a6de399b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

prompt-engineering 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 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.

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.

- **Golden rule**: show your prompt to a colleague with no context. If they'd be confused, the model will be too.
.ai/src/skills/prompt-engineering/SKILL.md · 118 lines

The source is not reproduced here

Licensed GPL-3.0

The repository is licensed GPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Files

What ships with it

3 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. 5d ago First seen · 118 lines · 171 tokens per session scan B 58d6a6de399b

Subscribe to this mod's changes

prompt-engineering is a skill published in the GitHub repository yelmuratoff/agent_sync (14 stars, last pushed 4d ago), licensed GPL-3.0. It adds 171 tokens to every session and 3,395 once invoked, about $0.0009 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 2026-08-30.

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