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LLM Prompt Optimizer

llm-prompt-optimizer

Use when improving prompts for any LLM. Applies proven prompt engineering techniques to boost output quality, reduce hallucinations, and cut token usage.

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SKILL.md

Full skill instructions

LLM Prompt Optimizer

Overview

This skill transforms weak, vague, or inconsistent prompts into precision-engineered instructions that reliably produce high-quality outputs from any LLM (Claude, Gemini, GPT-4, Llama, etc.). It applies systematic prompt engineering frameworks — from zero-shot to few-shot, chain-of-thought, and structured output patterns.

When to Use This Skill

  • Use when a prompt returns inconsistent, vague, or hallucinated results
  • Use when you need structured/​JSON output from an LLM reliably
  • Use when designing system prompts for AI agents or chatbots
  • Use when you want to reduce token usage without sacrificing quality
  • Use when implementing chain-of-thought reasoning for complex tasks
  • Use when prompts work on one model but fail on another

Step-by-Step Guide

1. Diagnose the Weak Prompt

Before optimizing, identify which problem pattern applies:

ProblemSymptomFix
Too vagueGeneric, unhelpful answersAdd role + context + constraints
No structureUnformatted, hard-to-parse outputSpecify output format explicitly
HallucinationConfident wrong answersAdd "say I don't know if unsure"
InconsistentDifferent answers each runAdd few-shot examples
Too longVerbose, padded responsesAdd length constraints

2. Apply the RSCIT Framework

Every optimized prompt should have:

  • R — Role: Who is the AI in this interaction?
  • S — Situation: What context does it need?
  • C — Constraints: What are the rules and limits?
  • I — Instructions: What exactly should it do?
  • T — Template: What should the output look like?

Before (weak prompt):

Explain machine learning.

After (optimized prompt):

You are a senior ML engineer explaining concepts to a junior developer.

Context: The developer has 1 year of Python experience but no ML background.

Task: Explain supervised machine learning in simple terms.

Constraints:
- Use an analogy from everyday life
- Maximum 200 words
- No mathematical formulas
- End with one actionable next step

Format: Plain prose, no bullet points.

3. Chain-of-Thought (CoT) Pattern

For reasoning tasks, instruct the model to think step-by-step:

Solve this problem step by step, showing your work at each stage.
Only provide the final answer after completing all reasoning steps.

Problem: [your problem here]

Thinking process:
Step 1: [identify what's given]
Step 2: [identify what's needed]
Step 3: [apply logic or formula]
Step 4: [verify the answer]

Final Answer:

4. Few-Shot Examples Pattern

Provide 2-3 examples to establish the pattern:

Classify the sentiment of customer reviews as POSITIVE, NEGATIVE, or NEUTRAL.

Examples:
Review: "This product exceeded my expectations!" -> POSITIVE
Review: "It arrived broken and support was useless." -> NEGATIVE  
Review: "Product works as described, nothing special." -> NEUTRAL

Now classify:
Review: "[your review here]" ->

5. Structured JSON Output Pattern

Extract the following information from the text below and return it as valid JSON only.
Do not include any explanation or markdown — just the raw JSON object.

Schema:
{
  "name": string,
  "email": string | null,
  "company": string | null,
  "role": string | null
}

Text: [input text here]

6. Reduce Hallucination Pattern

Answer the following question based ONLY on the provided context.
If the answer is not contained in the context, respond with exactly: "I don't have enough information to answer this."
Do not make up or infer information not present in the context.

Context:
[your context here]

Question: [your question here]

7. Prompt Compression Techniques

Reduce token count without losing effectiveness:

# Verbose (expensive)
"Please carefully analyze the following code and provide a detailed explanation of 
what it does, how it works, and any potential issues you might find."

# Compressed (efficient, same quality)
"Analyze this code: explain what it does, how it works, and flag any issues."

Best Practices

  • ✅ Do: Always specify the output format (JSON, markdown, plain text, bullet list)
  • ✅ Do: Use delimiters (```, ---) to separate instructions from content
  • ✅ Do: Test prompts with edge cases (empty input, unusual data)
  • ✅ Do: Version your system prompts in source control
  • ✅ Do: Add "think step by step" for math, logic, or multi-step tasks
  • ❌ Don't: Use negative-only instructions ("don't be verbose") — add positive alternatives
  • ❌ Don't: Assume the model knows your codebase context — always include it
  • ❌ Don't: Use the same prompt across different models without testing — they behave differently

Prompt Audit Checklist

Before using a prompt in production:

  • Does it have a clear role/​persona?
  • Is the output format explicitly defined?
  • Are edge cases handled (empty input, ambiguous data)?
  • Is