aither

Unified Rust traits for building AI applications across providers

Write AI applications that work with any provider 🚀

aither is a workspace of crates that gives you portable traits (LanguageModel, EmbeddingModel, ImageGenerator, …) plus thin provider bindings (aither-openai, aither-gemini, etc.). Build flows once and pick any backend that satisfies the traits—OpenAI, Gemini, local inference, or custom vendor endpoints.

┌─────────────────┐    ┌──────────────────┐    ┌─────────────────┐
│   Your App      │───▶│    aither        │◀───│   Providers     │
│                 │    │   (this crate)   │    │                 │
│ - Chat bots     │    │                  │    │ - openai        │
│ - Search        │    │ - LanguageModel  │    │ - anthropic     │
│ - Content gen   │    │ - EmbeddingModel │    │ - llama.cpp     │
│ - Voice apps    │    │ - ImageGenerator │    │ - whisper       │
└─────────────────┘    └──────────────────┘    └─────────────────┘

Highlights

• 🎯 Provider-agnostic traits – swap between OpenAI, Gemini, local adapters, or your own.
• ⚡ Streaming-first – every LanguageModel::respond returns a stream of Events: visible text deltas, reasoning updates, and tool calls.
• 🧠 Reasoning controls – request chain-of-thought summaries, budgets, or effort tiers without macros.
• 🛠️ Tooling & structured output – JSON-schema tools, builders, and derive macros keep function calling type-safe.
• 🧱 No-std capable – aither-core runs in embedded/WASM targets and re-exports only alloc.
• 📦 Batteries included – provider crates (openai, gemini) plus runnable examples (cargo run --example tool_macro).

Supported Capabilities

Quick Start

1. Choose a provider crate (aither-openai, aither-gemini, …) alongside aither for the shared traits:

[dependencies]
aither = { version = "0.1", features = ["serde", "derive"] }
aither-openai = "0.1"

2. Instantiate the provider, then drive everything through the trait:

use aither::{LanguageModel, llm::{Event, LLMRequest, Message}};
use aither_openai::OpenAI;
use futures_lite::StreamExt;

async fn basic_chat(api_key: &str) -> anyhow::Result<String> {
    let model = OpenAI::new(api_key);
    let request = LLMRequest::new([
        Message::system("You are a multilingual assistant."),
        Message::user("What is the capital of France?")
    ]);

    let mut stream = model.respond(request);
    let mut transcript = String::new();
    while let Some(event) = stream.next().await {
        if let Event::Text(chunk) = event? {
            transcript.push_str(&chunk);
        }
    }
    Ok(transcript)
}

Streaming Reasoning & Thinking Budgets

Reasoning-focused models (OpenAI O-series, Gemini Flash Thinking, etc.) expose chain-of-thought summaries as Event::Reasoning items in the same stream. You can request a thinking budget or reasoning effort via Parameters.

use aither::llm::{LanguageModel, Message, Request, model::Parameters};
use aither::{LanguageModel, llm::{Event, LLMRequest, Message, model::Parameters}};
use futures_lite::StreamExt;

async fn inspect_reasoning(model: impl LanguageModel) -> anyhow::Result<()> {
    let request = LLMRequest::new([
        Message::user("Solve 24 using numbers 4,4,4,4."),
    ])
    .with_parameters(
        Parameters::default()
            .include_reasoning(true)
            .reasoning_budget_tokens(256)
    );

    let mut stream = model.respond(request);
    let mut final_text = String::new();

    // Reasoning and visible text arrive interleaved in the same stream.
    while let Some(event) = stream.next().await {
        match event? {
            Event::Reasoning(thought) => println!("🤔 {thought}"),
            Event::Text(chunk) => final_text.push_str(&chunk),
            _ => {}
        }
    }

    println!("Answer: {final_text}");
    Ok(())
}

Function Calling

use aither::llm::{LLMRequest, Message, Tool, ToolOutput};
use schemars::JsonSchema;
use serde::Deserialize;
use std::borrow::Cow;

/// Get current weather for a location.
#[derive(JsonSchema, Deserialize)]
struct WeatherQuery {
    /// City to report on, e.g. "Tokyo".
    location: String,
}

struct WeatherTool;

impl Tool for WeatherTool {
    fn name(&self) -> Cow<'static, str> {
        Cow::Borrowed("get_weather")
    }

    type Arguments = WeatherQuery;

    async fn call(&self, args: Self::Arguments) -> aither::Result<ToolOutput> {
        Ok(ToolOutput::text(format!("Weather in {}: 22°C, sunny", args.location)))
    }
}

// Advertise the tool on the request. The model answers with an
// `Event::ToolCall`; running it and feeding the result back is the caller's
// job, or `aither-agent`'s.
let request = LLMRequest::new([Message::user("What is the weather in Tokyo?")])
    .with_tool(&WeatherTool);

The tool's description defaults to the rustdoc on its Arguments type. Override Tool::description() to set it explicitly — a tool with neither is rejected at registration rather than reaching the model unexplained.

Semantic Search & Multimodal

See examples/chatbot_gemini.rs, examples/chatbot_openrouter.rs, and examples/tool_macro.rs for end-to-end demos that combine embeddings, multimodal prompts, and structured outputs. Each example can be run with:

cargo run --example tool_macro --features derive

Progressive Image Generation

use aither::{ImageGenerator, image::{Prompt, Size}};
use futures_lite::StreamExt;

async fn generate_image(generator: impl ImageGenerator) -> aither::Result<Vec<u8>> {
    let prompt = Prompt::new("A beautiful sunset over mountains");
    let size = Size::square(1024);
    
    let mut image_stream = generator.create(prompt, size);
    let mut final_image = Vec::new();
    
    while let Some(image_result) = image_stream.next().await {
        final_image = image_result?;
        println!("Received image update, {} bytes", final_image.len());
    }
    
    Ok(final_image)
}

Workspace Layout

Development

Use the same commands as CI:

cargo fmt --all
cargo clippy --all-targets --all-features --workspace -- -D warnings
cargo test --all-features --workspace

To try reasoning/tooling flows locally:

# Stream reasoning with tools enabled
OPENAI_API_KEY=sk-... cargo run --example tool_macro -p aither-openai

# Gemini thinking-budget demo
GEMINI_API_KEY=... cargo run --example chatbot_gemini -p aither-gemini

License

MIT License - see LICENSE for details.