Agent skill

Prompt Engineering Expert

by alecs5am in alecs5am/ralphy

Expert prompt engineering, custom instruction, system prompt, and agent instruction design.

MITAuto-check passedAI & LLM Engineering

Install Prompt Engineering Expert

skills CLI
$ npx skills add alecs5am/ralphy --skill prompt-engineering-expert -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install alecs5am/ralphy prompt-engineering-expert --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/alecs5am/ralphy.git skills-src && mkdir -p .claude/skills && cp -r skills-src/notes/skills/prompt-engineering-expert .claude/skills/prompt-engineering-expert && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
prompt-engineering-expert
GitHub stars
138
Token cost
~1.4k tokens
SKILL.md length
679 words
Files
6 (incl. references)
Skills in repo
28
Repo updated
First seen
Licence
MIT

At a glance

Expert prompt engineering, custom instruction, system prompt, and agent instruction design.

  • Codex needs to review
  • SKILL.md covers Workflow, Response Pattern, Core Principles and Technique Selection, plus 4 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
  • Test AI prompts

What it does

Prompt Engineering Expert is an agent skill from alecs5am/ralphy. Expert prompt engineering, custom instruction, system prompt, and agent instruction design. Use when Codex needs to review, generate, refactor, debug, optimize, document, or test AI prompts; design reusable prompt templates; create or improve system prompts, custom instructions, agent behavior guidelines, tool-use prompts, multimodal prompts, or prompt evaluation frameworks.

Its SKILL.md is about 1.4k tokens, which your agent loads only when the skill is triggered. The skill folder holds 7 other files, including reference files (for example `references/agents/openai.yaml`, `references/evaluation.md` and `references/examples.md`).

It sits in AI & LLM Engineering, covering Prompt engineering. The repository describes itself as: Open-source desktop app for content creation, with an agent runtime and standalone CLI. The licence is MIT.

When your agent uses it

  • Codex needs to review
  • Test AI prompts
  • Design reusable prompt templates
  • Improve system prompts

Example prompts

  • “/prompt-engineering-expert”

What it can do on your machine

Read from SKILL.md and the folder at commit 8d139f0. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Prompt Engineering Expert loads about 1.4k tokens when it runs, and up to ~4.7k if it reads all its reference files. Until then it costs about 101 tokens; SKILL.md has 679 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~101
When it runs · the whole SKILL.md, loaded when a task matches
~1.4k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~4.7k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from alecs5am/ralphy at commit 8d139f0, republished under its MIT licence (© alecs5am). 679 words, ~1,429 tokens.

Download SKILL.mdSave it as .claude/skills/prompt-engineering-expert/SKILL.md (or your agent's skills folder). This skill also uses 5 other files; get the full folder from GitHub.
name
prompt-engineering-expert
description
Expert prompt engineering, custom instruction, system prompt, and agent instruction design. Use when Codex needs to review, generate, refactor, debug, optimize, document, or test AI prompts; design reusable prompt templates; create or improve system prompts, custom instructions, agent behavior guidelines, tool-use prompts, multimodal prompts, or prompt evaluation frameworks.
license
MIT

Prompt Engineering Expert

Use this skill to make prompts clearer, more reliable, easier to evaluate, and better matched to the model, task, tools, and operating context.

Workflow

Identify the prompt's job: task, audience, model or agent context, available tools, inputs, output consumers, and failure cost. Diagnose weaknesses before rewriting: ambiguity, missing context, conflicting instructions, brittle examples, unsafe scope, untestable success criteria, output format gaps, or token bloat. Choose the lightest effective technique: direct instructions first; add roles, examples, structured tags, staged reasoning, tool-use guidance, or prompt chaining only when they solve a concrete issue. Produce an improved prompt or instruction set with enough surrounding explanation for the user to evaluate the tradeoffs. Define validation: expected behaviors, edge cases, regression cases, and success criteria.

Response Pattern

For prompt reviews, prefer this structure:

  • Diagnosis: the highest-impact issues, ordered by severity.
  • Revision: a ready-to-use improved prompt.
  • Why It Works: concise rationale for major changes.
  • Tests: representative cases the user should run.

For prompt generation, prefer:

  • Ask for missing high-risk constraints only if they cannot be reasonably assumed.
  • Otherwise state assumptions and draft the prompt.
  • Include variables/placeholders when the prompt should be reusable.
  • Include a short evaluation checklist.

Core Principles

  • Make the task objective explicit.
  • Give only the context needed to perform the task.
  • State non-negotiable constraints separately from preferences.
  • Specify the expected output format when downstream use matters.
  • Use examples to teach patterns, not to smuggle one-off answers.
  • Avoid hidden contradictions between role, task, constraints, and format.
  • Prefer observable success criteria over subjective goals such as "high quality" or "good."
  • Preserve model flexibility where multiple valid answers exist.
  • Add safeguards for uncertainty: cite provided evidence, mark assumptions, and say what is unknown.

Technique Selection

  • Direct instruction: default for simple tasks.
  • Few-shot examples: use when format, categorization, tone, or edge-case handling must be learned from examples.
  • Structured tags or schemas: use when inputs, constraints, and outputs need clear boundaries or machine parsing.
  • Role framing: use only when expertise, tone, or decision standards change the output.
  • Staged reasoning or decomposition: use when the task has separable phases or frequent reasoning mistakes.
  • Prompt chaining: use when one prompt is overloaded with extraction, analysis, transformation, and generation.
  • Tool-use instructions: use when the agent must decide when to call tools, how to validate tool output, or how to recover from tool errors.
  • Multimodal instructions: use when images, PDFs, spreadsheets, code, or other files require explicit inspection targets.
  • See references/techniques.md [blocked] for patterns and compact examples.
Show full SKILL.md (272 more words)Show less

Custom Instructions And Agent Prompts

When designing system prompts, custom instructions, or agent skills:

  • Define the agent's role through responsibilities and decision standards, not theatrical persona.
  • Separate mandatory behavior from style preferences.
  • Include boundaries: what to refuse, what to escalate, what to ask about, and what to infer.
  • Keep instructions stable across turns; avoid directions that require mutating past context.
  • For tool-using agents, specify tool selection, validation, retry, and user-update behavior.
  • For coding agents, include repository conventions, test expectations, and change-safety rules.

Anti-Patterns Watch for:

Vague verbs: "analyze," "improve," "make better," "handle this."

Contradictions: "be concise" plus many mandatory sections, or "do not ask questions" plus missing required data. Overfitted examples that teach accidental details. Output formats described in prose when a schema or example is needed. Prompts that invite hallucination by asking for facts without sources or data. Security gaps: untrusted user content can override instructions, leak context, or request unsafe actions. Token bloat from background essays, duplicated rules, and unused options. See references/troubleshooting.md [blocked] for failure modes and fixes.

Evaluation

Every non-trivial prompt improvement should include tests:

  • Happy path with typical input.
  • Edge case with missing, ambiguous, or malformed input.
  • Regression case for a known failure.
  • Adversarial or injection case when untrusted input is involved.
  • Format compliance case when downstream parsing matters.
  • See references/evaluation.md [blocked] for test templates and scoring rubrics.

Reference Loading

Load only the references needed for the request:

  • references/techniques.md [blocked]: prompting techniques, when to use each, and compact examples.
  • references/troubleshooting.md [blocked]: common prompt failures, diagnosis, and fixes.
  • references/evaluation.md [blocked]: prompt test cases, rubrics, and regression strategy.
  • references/examples.md [blocked]: reusable prompt review, generation, classification, structured-output, and agent-instruction examples.

© alecs5am, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 5 other files (references) in notes/skills/prompt-engineering-expert of alecs5am/ralphy.

  • SKILL.md
  • references/agents/openai.yaml
  • references/evaluation.md
  • references/examples.md
  • references/techniques.md
  • references/troubleshooting.md

Open the folder on GitHubat commit 8d139f0

Compare with similar skills

Prompt Engineering Expert next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Prompt Engineering Expert compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Prompt Engineering Expert this skillalecs5am/ralphy138—~1.4kAutomated safety check: PassMIT
Prompt Improverseverity1/claude-code-prompt-improver1.9k1 repos~1.7kAutomated safety check: PassMIT
Prompt Engineering Patternsynulihao/AgentSkillOS61814 repos~1.7kAutomated safety check: PassNone
Patch CreationPiebald-AI/tweakcc2.5k—~1.6kAutomated safety check: PassMIT
Senior Prompt Engineermaslennikov-ig/claude-code-orchestrator-kit2603 repos~1.4kAutomated safety check: PassCustom licence
Codex Fable5baskduf/FableCodex437—~1.6kAutomated safety check: PassAGPL-3.0

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  • Prompt Improver

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Questions about Prompt Engineering Expert

What does Prompt Engineering Expert do?

Expert prompt engineering, custom instruction, system prompt, and agent instruction design. Prompt Engineering Expert is an agent skill from alecs5am/ralphy. Expert prompt engineering, custom instruction, system prompt, and agent instruction design.

When should I use Prompt Engineering Expert?

Prompt Engineering Expert fits situations like: Codex needs to review; test AI prompts; design reusable prompt templates; improve system prompts.

How do I install Prompt Engineering Expert in Claude Code?

Run `npx skills add alecs5am/ralphy --skill prompt-engineering-expert -a claude-code`. Or copy the skill folder (notes/skills/prompt-engineering-expert in alecs5am/ralphy) into .claude/skills/prompt-engineering-expert in your project. Claude Code loads it when a task matches its description.

How do I install Prompt Engineering Expert in Codex?

Run `npx skills add alecs5am/ralphy --skill prompt-engineering-expert -a codex`. Or copy the skill folder (notes/skills/prompt-engineering-expert in alecs5am/ralphy) into .agents/skills/prompt-engineering-expert in your project. Codex loads it when a task matches its description.

Can I use Prompt Engineering Expert in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add alecs5am/ralphy --skill prompt-engineering-expert -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/prompt-engineering-expert, .gemini/skills/prompt-engineering-expert, .github/skills/prompt-engineering-expert and .opencode/skills/prompt-engineering-expert in your project.

What does Prompt Engineering Expert need to run?

SKILL.md names no scripts, command-line tools or credentials: Prompt Engineering Expert is instructions for the agent only.

Does Prompt Engineering Expert access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Prompt Engineering Expert safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Prompt Engineering Expert use?

Prompt Engineering Expert is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Prompt Engineering Expert use?

About 1.4k tokens (SKILL.md is roughly 5.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 3.3k tokens, read only when the agent opens those files.

What are the alternatives to Prompt Engineering Expert?

Skills that share tags, products or a category with Prompt Engineering Expert: Prompt Improver (severity1/claude-code-prompt-improver, 1.9k stars), Prompt Engineering Patterns (ynulihao/AgentSkillOS, 618 stars), Patch Creation (Piebald-AI/tweakcc, 2.5k stars) and Senior Prompt Engineer (maslennikov-ig/claude-code-orchestrator-kit, 260 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Prompt Engineering Expert?

alecs5am (a GitHub user) maintains it in alecs5am/ralphy, which has 138 GitHub stars. The repository holds 28 skills in this directory. The repository was last updated on September 22, 2026.

Source: alecs5am/ralphy on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.