🚅 LiteLLM

uv add litellm

python scripts/build_core_distribution.py --out-dir dist/core
python -m pip install dist/core/litellm_core-*.whl

from litellm import completion
import os

os.environ["OPENAI_API_KEY"] = "your-openai-key"
os.environ["ANTHROPIC_API_KEY"] = "your-anthropic-key"

# OpenAI
response = completion(model="openai/gpt-4o", messages=[{"role": "user", "content": "Hello!"}])

# Anthropic  
response = completion(model="anthropic/claude-sonnet-4-20250514", messages=[{"role": "user", "content": "Hello!"}])

uv tool install 'litellm[proxy]'
litellm --model gpt-4o

import openai

client = openai.OpenAI(api_key="anything", base_url="http://0.0.0.0:4000")
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Hello!"}]
)

import asyncio
from litellm import Router

router = Router(model_list=[
    {"model_name": "fast", "litellm_params": {"model": "openai/gpt-6-luna"}},
    {"model_name": "capable", "litellm_params": {"model": "openai/gpt-6.1-sol"}},
    {"model_name": "auto", "litellm_params": {
        "model": "auto_router/complexity_router",
        "complexity_router_config": {
            "classifier_type": "heuristic",
            "tiers": {"SIMPLE": "fast", "MEDIUM": "fast",
                      "COMPLEX": "capable", "REASONING": "capable"},
            "return_raw_model_name": True,
        },
        "complexity_router_default_model": "capable",
    }},
])
response = asyncio.run(router.acompletion(
    model="auto", messages=[{"role": "user", "content": "What is 2+2?"}],
))
print(response.model, response.choices[0].message.content)

curl http://localhost:4000/v1/chat/completions \
  -H "Authorization: Bearer $LITELLM_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"auto","messages":[{"role":"user","content":"What is 2+2?"}]}'

from litellm.a2a_protocol import A2AClient
from a2a.types import SendMessageRequest, MessageSendParams
from uuid import uuid4

client = A2AClient(base_url="http://localhost:10001")

request = SendMessageRequest(
    id=str(uuid4()),
    params=MessageSendParams(
        message={
            "role": "user",
            "parts": [{"kind": "text", "text": "Hello!"}],
            "messageId": uuid4().hex,
        }
    )
)
response = await client.send_message(request)