### Simple OpenAI Completion Example

Source: https://docs.rs/rig-core/latest/rig_core

Demonstrates how to create an OpenAI client, build an agent for a specific model (GPT-5.2), and prompt it for a completion. Requires the OPENAI_API_KEY environment variable to be set.

```rust
use rig_core::
    client::{CompletionClient, ProviderClient},
    completion::Prompt,
    providers::openai;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create OpenAI client and agent.
    // This requires the `OPENAI_API_KEY` environment variable to be set.
    let openai_client = openai::Client::from_env()?;

    let agent = openai_client.agent(openai::GPT_5_2).build();

    // Prompt the model and print its response
    let response = agent
        .prompt("Who are you?")
        .await?;

    println!("{response}");

    Ok(())
}

```

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