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Basic Examples

Simple, practical examples to get started with Promptel.

Hello World

The simplest possible prompt:

prompt HelloWorld {
  body {
    text`Say hello to the world in a friendly way.`
  }
}

name: HelloWorld
body:
  text: "Say hello to the world in a friendly way."

const { executePrompt } = require('promptel');

const result = await executePrompt(`
prompt HelloWorld {
  body { text\`Say hello to the world in a friendly way.\` }
}
`);

console.log(result);

With Parameters

Accept input parameters:

prompt Greeter {
  params {
    name: string
    language?: string = "English"
  }

  body {
    text`Greet ${params.name} warmly in ${params.language}.`
  }
}

name: Greeter

params:
  name:
    type: string
    required: true
  language:
    type: string
    required: false
    default: "English"

body:
  text: "Greet ${params.name} warmly in ${params.language}."

const result = await executePrompt(greeterPrompt, {
  name: "Alice",
  language: "Spanish"
});

Text Summarizer

Summarize text with constraints:

prompt Summarizer {
  params {
    text: string
    sentences?: number = 3
  }

  body {
    text`Summarize the following text in ${params.sentences} sentences:

${params.text}

Be concise and capture the main points.`
  }

  constraints {
    maxTokens: 200
    temperature: 0.5
  }
}

name: Summarizer

params:
  text:
    type: string
    required: true
  sentences:
    type: number
    default: 3

body:
  text: |
    Summarize the following text in ${params.sentences} sentences:

    ${params.text}

    Be concise and capture the main points.

constraints:
  maxTokens: 200
  temperature: 0.5

Sentiment Analyzer

Classify sentiment with few-shot examples:

prompt SentimentAnalyzer {
  params {
    text: string
  }

  body {
    text`Classify the sentiment of: "${params.text}"`
  }

  technique {
    fewShot {
      example {
        input: "I absolutely love this product!"
        output: "positive"
      }
      example {
        input: "This is the worst experience ever."
        output: "negative"
      }
      example {
        input: "It's okay, nothing special."
        output: "neutral"
      }
    }
  }

  constraints {
    maxTokens: 10
    temperature: 0
  }
}

Usage:

const result = await executePrompt(sentimentPrompt, {
  text: "The service was excellent and staff were friendly!"
});
// Result: "positive"

Code Explainer

Explain code in plain language:

prompt CodeExplainer {
  params {
    code: string
    language?: string = "JavaScript"
    audience?: string = "beginner"
  }

  body {
    text`Explain this ${params.language} code for a ${params.audience}:

\`\`\`${params.language}
${params.code}
\`\`\`

Explain what it does, line by line if helpful.`
  }

  constraints {
    maxTokens: 500
    temperature: 0.3
  }
}

Usage:

const result = await executePrompt(explainerPrompt, {
  code: `const sum = arr.reduce((a, b) => a + b, 0);`,
  language: "JavaScript",
  audience: "beginner"
});

Email Writer

Generate professional emails:

prompt EmailWriter {
  params {
    recipient: string
    subject: string
    keyPoints: string
    tone?: string = "professional"
  }

  body {
    text`Write a ${params.tone} email to ${params.recipient}.

Subject: ${params.subject}

Key points to cover:
${params.keyPoints}

The email should be clear, concise, and appropriate for business communication.`
  }

  constraints {
    maxTokens: 400
    temperature: 0.7
  }
}

Question Answerer

Answer questions with context:

prompt QABot {
  params {
    context: string
    question: string
  }

  body {
    text`Based on the following context, answer the question.

Context:
${params.context}

Question: ${params.question}

Answer based only on the information provided. If the answer isn't in the context, say "I don't have enough information to answer that."`
  }

  constraints {
    maxTokens: 300
    temperature: 0.3
  }
}

Translation

Translate text between languages:

prompt Translator {
  params {
    text: string
    sourceLang?: string = "auto"
    targetLang: string
  }

  body {
    text`Translate the following from ${params.sourceLang} to ${params.targetLang}:

${params.text}

Provide only the translation, preserving tone and meaning.`
  }

  constraints {
    temperature: 0.3
  }
}

Data Formatter

Convert data between formats:

prompt DataFormatter {
  params {
    data: string
    inputFormat: string
    outputFormat: string
  }

  body {
    text`Convert this ${params.inputFormat} to ${params.outputFormat}:

${params.data}

Output only the converted data, no explanation.`
  }

  constraints {
    temperature: 0
  }
}

Usage:

const result = await executePrompt(formatterPrompt, {
  data: "name,age,city\nAlice,30,NYC\nBob,25,LA",
  inputFormat: "CSV",
  outputFormat: "JSON"
});

CLI Examples

Run any of these from the command line:

# Create a prompt file
cat > summarizer.prompt << 'EOF'
prompt Summarizer {
  params {
    text: string
  }
  body {
    text`Summarize: ${params.text}`
  }
}
EOF

# Execute it
promptel -f summarizer.prompt -p openai -k $OPENAI_API_KEY \
  --params '{"text":"Your long text here..."}'

Next Steps