prompt-engineer

prompt-engineer is a skill for Codex from vladolaru/claude-code-plugins. It costs 42 tokens per session (4,729 once invoked), scanned A, original, MIT.

A prompt-improvement guide for instructions used by coding agents and other automated workflows. It applies established techniques to make those instructions clearer and more consistent.

In plain words
What is it for?
Use it to improve agent prompts, tool instructions, system behaviors, skill files, and related configuration. It supports work in Claude Code and Codex workflows.
Why use it?
It helps remove ambiguous or conflicting directions that can cause an agent to behave unpredictably. It also checks that each change has a stated reason and expected effect.

Skill for Codex

Written for Codex: agents/openai.yaml present. Also seen: mentions subagents; mentions Claude Code; mentions Codex.

Good fit Use it to improve agent prompts, tool instructions, system behaviors, skill files, and related configuration. It supports work in Claude Code and Codex workflows.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/vladolaru/claude-code-plugins/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.

Any agent
npx skills add vladolaru/claude-code-plugins --skill prompt-engineer
Clone the repo
git clone --depth 1 https://github.com/vladolaru/claude-code-plugins

Made for: 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-engineer

README.md
[![agentmods](https://agentmods.dev/badge/skills/vladolaru/claude-code-plugins/prompt-engineer/github.svg)](https://agentmods.dev/skills/vladolaru/claude-code-plugins/prompt-engineer)
Your own site
<a href="https://agentmods.dev/skills/vladolaru/claude-code-plugins/prompt-engineer"><img src="https://agentmods.dev/badge/skills/vladolaru/claude-code-plugins/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/vladolaru/claude-code-plugins/prompt-engineer"><img src="https://agentmods.dev/badge/skills/vladolaru/claude-code-plugins/prompt-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,729 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 pass 7 Sept 2026
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 $0.00042 $0.04729
Opus 5 $0.00021 $0.02364
Sonnet 5 $0.00008 $0.00946
Haiku 4.5 $0.00004 $0.00473

Measured 12d ago against content hash f0c4b275169e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-15, 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 12d 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.

plugins/prompt-engineer/codex-skills/prompt-engineer/SKILL.md · 537 lines

How it starts

The opening of the file, as written. The whole thing — 537 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Directory

Resolve SKILL_DIR to the absolute directory containing this SKILL.md, as shown by the current host, before using any bundled path below. Before a shell command uses $SKILL_DIR, assign it in that command or replace it with the resolved path. It is not a host-exported environment variable.

Prompt Optimizer

Optimizes system prompts by applying research-backed prompt engineering patterns. This skill operates through human-in-the-loop phases: understand, plan, propose changes, receive approval, then integrate.

Purpose and Success Criteria

A well-optimized prompt achieves three things:

  1. Behavioral clarity: The agent knows exactly what to do in common cases and how to handle edge cases.
  2. Appropriate scope: Complex tasks get systematic decomposition; simple tasks don't trigger overthinking.
  3. Grounded changes: Every modification traces to a specific pattern with documented behavioral impact.

Optimization is complete when:

  • Every change has explicit pattern attribution from the reference document
  • No section contradicts another section
  • The prompt matches its operating context (tool-use vs. conversational, token constraints, failure modes)
  • Human has approved both section-level changes and full integration

When to Use This Skill

Use when the user provides a prompt and wants it improved, refined, or reviewed for best practices.

Do NOT use for:

  • Writing prompts from scratch (different skill)
  • Prompts that are already working well and user just wants validation (say so, don't force changes)
  • Non-prompt content (documentation, code, etc.)

Required Resources

Before ANY analysis, read the appropriate pattern reference(s). Each reference contains a Technique Selection Guide table mapping domains, trigger conditions, stacking compatibility, conflicts, and expected effects.

Single-Turn Reference (Always Read)

$SKILL_DIR/references/prompt-engineering-single-turn.md

Read the full file on GitHub · 537 lines

Files

What ships with it

7 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. 12d ago First seen · 537 lines · 42 tokens per session scan A f0c4b275169e

Subscribe to this mod's changes

prompt-engineer is a skill published in the GitHub repository vladolaru/claude-code-plugins (8 stars, last pushed today), licensed MIT. It adds 42 tokens to every session and 4,729 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 2026-09-03.

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