Send your first prompt

This guide takes you from an empty project to a working LLM call in each of the four SDKs. The shape is identical everywhere: construct a provider-bound client, chain the text builder with a model and a prompt, read the reply off the response.

Before you start

Set the API key for the provider you want to call. The keys are read from the environment:

export ANTHROPIC_API_KEY="sk-ant-..."
export OPENAI_API_KEY="sk-..."
export GOOGLE_API_KEY="..."

The examples below call Anthropic with claude-opus-4-7. Swap the builder (anthropic -> openai, google, …) and the model string to target a different provider — the call surface does not change.

Go

package main

import (
	"context"
	"fmt"
	"log"
	"os"

	llmkit "github.com/aktagon/llmkit-go"
)

func main() {
	c := llmkit.New("anthropic", os.Getenv("ANTHROPIC_API_KEY"))
	resp, err := c.Text.
		Model("claude-opus-4-7").
		Prompt(context.Background(), "Explain prompt caching in two sentences.")
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(resp.Text)
	fmt.Printf("tokens: in=%d out=%d\n", resp.Usage.Input, resp.Usage.Output)
}

c.Text is a field on *Client, not a method call. Chain methods clone the prototype and return a fresh builder.

TypeScript

import { anthropic } from "@aktagon/llmkit-ts/builders";

const c = anthropic(process.env.ANTHROPIC_API_KEY!);
const resp = await c.text
  .model("claude-opus-4-7")
  .prompt("Explain prompt caching in two sentences.");

console.log(resp.text);
console.log(`tokens: in=${resp.usage.input} out=${resp.usage.output}`);

Python

import os
import asyncio
from llmkit.builders import anthropic

async def main():
    c = anthropic(os.environ["ANTHROPIC_API_KEY"])
    resp = await (
        c.text
        .model("claude-opus-4-7")
        .prompt("Explain prompt caching in two sentences.")
    )
    print(resp.text)
    print(f"tokens: in={resp.usage.input} out={resp.usage.output}")

asyncio.run(main())

Rust

use llmkit::builders::anthropic;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let c = anthropic(std::env::var("ANTHROPIC_API_KEY")?);
    let resp = c
        .text()
        .model("claude-opus-4-7")
        .prompt("Explain prompt caching in two sentences.")
        .await?;

    println!("{}", resp.text);
    println!("tokens: in={} out={}", resp.usage.input, resp.usage.output);
    Ok(())
}

Note Rust accesses the text builder as c.text() (a method), where Go, TypeScript, and Python use c.Text / c.text as a field.

Send your first prompt

Before you start

Go

TypeScript

Python

Rust

What to read next