From .prompt to result.

promptel ships on npm and runs on Node.js 18 or newer. Add it to any project — or run the CLI without installing.

$ npm install promptel

Author the prompt in the DSL: typed params, a body, and a technique block. Params are declared with types and defaults so the executor can refuse a prompt that does not bind.

# summarizer.prompt
prompt Summarizer {
  params {
    text: string
    style?: string = "concise"
  }
  body {
    text`Summarize the following in a ${params.style} way:

    ${params.text}`
    technique {
      chainOfThought {
        step("Read")    { text`Identify the key claims` }
        step("Compress"){ text`State them in two sentences` }
      }
    }
  }
  constraints { maxTokens: 200; temperature: 0.2 }
}

executePrompt takes the source, the params, and options. Choose the provider at call time — the same file runs against OpenAI, Anthropic, or Groq.

import { executePrompt } from 'promptel';
import { readFileSync } from 'node:fs';

const src = readFileSync('summarizer.prompt', 'utf8');
const result = await executePrompt(src, { text: article }, {
  provider: 'openai'
});
console.log(result);

The promptel CLI executes a prompt against a provider and can write structured results to a file — handy for evals and CI.

$ promptel -f summarizer.prompt -p openai \
    --params '{"text":"..."}' -o result.json

The DSL and YAML surfaces are equivalent. Convert either direction with one CLI flag when tooling prefers YAML for schema validation or codegen.

$ promptel --convert yaml -f summarizer.prompt -o summarizer.yml