Install the belt CLI skill: npx skills add belt-sh/cli

Prompt Engineering Guide

Master prompt engineering for AI models via inference.sh CLI.

Quick Start

Requires inference.sh CLI (belt). Install instructions

belt login

Well-structured LLM prompt

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "You are a senior software engineer. Review this code for security vulnerabilities:\n\npython\nuser_input = request.args.get(\"query\")\nresult = db.execute(f\"SELECT * FROM users WHERE name = {user_input}\")\n\n\nProvide specific issues and fixes."

}'

## LLM Prompting

### Basic Structure

[Role/Context] + [Task] + [Constraints] + [Output Format]

### Role Prompting

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "You are an expert data scientist with 15 years of experience in machine learning. Explain gradient descent to a beginner, using simple analogies."

}'

### Task Clarity

Bad: vague

"Help me with my code"

Good: specific

"Debug this Python function that should return the sum of even numbers from a list, but returns 0 for all inputs:

def sum_evens(numbers):

total = 0

for n in numbers:

if n % 2 == 0:

total += n

return total

Identify the bug and provide the corrected code."

### Chain-of-Thought

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "Solve this step by step:\n\nA store sells apples for $2 each and oranges for $3 each. If someone buys 5 fruits and spends $12, how many of each fruit did they buy?\n\nThink through this step by step before giving the final answer."

}'

### Few-Shot Examples

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "Convert these sentences to formal business English:\n\nExample 1:\nInput: gonna send u the report tmrw\nOutput: I will send you the report tomorrow.\n\nExample 2:\nInput: cant make the meeting, something came up\nOutput: I apologize, but I will be unable to attend the meeting due to an unforeseen circumstance.\n\nNow convert:\nInput: hey can we push the deadline back a bit?"

}'

### Output Format Specification

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "Analyze the sentiment of these customer reviews. Return a JSON array with objects containing \"text\", \"sentiment\" (positive/negative/neutral), and \"confidence\" (0-1).\n\nReviews:\n1. \"Great product, fast shipping!\"\n2. \"Meh, its okay I guess\"\n3. \"Worst purchase ever, total waste of money\"\n\nReturn only valid JSON, no explanation."

}'

### Constraint Setting

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "Summarize this article in exactly 3 bullet points. Each bullet must be under 20 words. Focus only on actionable insights, not background information.\n\n[article text]"

}'

## Image Generation Prompting

### Basic Structure

[Subject] + [Style] + [Composition] + [Lighting] + [Technical]

### Subject Description

Bad: vague

"a cat"

Good: specific

belt app run falai/flux-dev --input '{

"prompt": "A fluffy orange tabby cat with green eyes, sitting on a vintage leather armchair"

}'

### Style Keywords

belt app run falai/flux-dev --input '{

"prompt": "Portrait photograph of a woman, shot on Kodak Portra 400 film, soft natural lighting, shallow depth of field, nostalgic mood, analog photography aesthetic"

}'

### Composition Control

belt app run falai/flux-dev --input '{

"prompt": "Wide establishing shot of a cyberpunk city skyline at night, rule of thirds composition, neon signs in foreground, towering skyscrapers in background, rain-slicked streets"

}'

### Quality Keywords

photorealistic, 8K, ultra detailed, sharp focus, professional,

masterpiece, high quality, best quality, intricate details

### Negative Prompts

belt app run falai/flux-dev --input '{

"prompt": "Professional headshot portrait, clean background",

"negative_prompt": "blurry, distorted, extra limbs, watermark, text, low quality, cartoon, anime"

}'

## Video Prompting

### Basic Structure

[Shot Type] + [Subject] + [Action] + [Setting] + [Style]

### Camera Movement

belt app run google/veo-3-1-fast --input '{

"prompt": "Slow tracking shot following a woman walking through a sunlit forest, golden hour lighting, shallow depth of field, cinematic, 4K"

}'

### Action Description

belt app run google/veo-3-1-fast --input '{

"prompt": "Close-up of hands kneading bread dough on a wooden surface, flour dust floating in morning light, slow motion, cozy baking aesthetic"

}'

### Temporal Keywords

slow motion, timelapse, real-time, smooth motion,

continuous shot, quick cuts, frozen moment

## Advanced Techniques

### System Prompts

belt app run openrouter/claude-sonnet-45 --input '{

"system": "You are a helpful coding assistant. Always provide code with comments. If you are unsure about something, say so rather than guessing.",

"prompt": "Write a Python function to validate email addresses using regex."

}'

### Structured Output

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "Extract information from this text and return as JSON:\n\n\"John Smith, CEO of TechCorp, announced yesterday that the company raised $50 million in Series B funding. The round was led by Venture Partners.\"\n\nSchema:\n{\n \"person\": string,\n \"title\": string,\n \"company\": string,\n \"event\": string,\n \"amount\": string,\n \"investor\": string\n}"

}'

### Iterative Refinement

Start broad

belt app run falai/flux-dev --input '{

"prompt": "A castle on a hill"

}'

Add specifics

belt app run falai/flux-dev --input '{

"prompt": "A medieval stone castle on a grassy hill"

}'

Add style

belt app run falai/flux-dev --input '{

"prompt": "A medieval stone castle on a grassy hill, dramatic sunset sky, fantasy art style, epic composition"

}'

Add technical

belt app run falai/flux-dev --input '{

"prompt": "A medieval stone castle on a grassy hill, dramatic sunset sky, fantasy art style by Greg Rutkowski, epic composition, 8K, highly detailed"

}'

### Multi-Turn Reasoning

First: analyze

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "Analyze this business problem: Our e-commerce site has a 70% cart abandonment rate. List potential causes."

}'

Second: prioritize

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "Given these causes of cart abandonment: [previous output], rank them by likely impact and ease of fixing. Format as a priority matrix."

}'

Third: action plan

belt app run openrouter/claude-sonnet-45 --input '{

"prompt": "For the top 3 causes identified, provide specific A/B tests we can run to validate and fix each issue."

}'

## Model-Specific Tips

### Claude

- Excels at nuanced instructions

- Responds well to role-playing

- Good at following complex constraints

- Prefers explicit output formats

### GPT-4

- Strong at code generation

- Works well with examples

- Good structured output

- Responds to "let's think step by step"

### FLUX

- Detailed subject descriptions

- Style references work well

- Lighting keywords important

- Negative prompts supported

### Veo

- Camera movement keywords

- Cinematic language works well

- Action descriptions important

- Include temporal context

## Common Mistakes

Mistake
Problem
Fix

Too vague
Unpredictable output
Add specifics

Too long
Model loses focus
Prioritize key info

Conflicting
Confuses model
Remove contradictions

No format
Inconsistent output
Specify format

No examples
Unclear expectations
Add few-shot

## Prompt Templates

### Code Review

Review this [language] code for:

1. Bugs and logic errors

1. Security vulnerabilities

1. Performance issues

1. Code style/best practices

Code:

[code]

For each issue found, provide:

• Line number

• Issue description

• Severity (high/medium/low)

• Suggested fix

### Content Writing

Write a [content type] about [topic].

Audience: [target audience]

Tone: [formal/casual/professional]

Length: [word count]

Key points to cover:

1. [point 1]

1. [point 2]

1. [point 3]

Include: [specific elements]

Avoid: [things to exclude]

### Image Generation

[Subject with details], [setting/background], [lighting type],

[art style or photography style], [composition], [quality keywords]

## Related Skills

Video prompting guide

npx skills add inference-sh/skills@video-prompting-guide

LLM models

npx skills add inference-sh/skills@llm-models

Image generation

npx skills add inference-sh/skills@ai-image-generation

Full platform skill

npx skills add inference-sh/skills@infsh-cli