kreuzberg-dev Calling LLMs
Build a ChatCompletionRequest and send it with client.chat(request). Create
the client with create_client(...). The model string is provider/model; the
prefix selects the backend.
import asyncio, json, os
from liter_llm import create_client
from liter_llm._internal_bindings import ChatCompletionRequest
async def main() -> None:
client = create_client(api_key=os.environ["OPENAI_API_KEY"])
request = ChatCompletionRequest.from_json(json.dumps({
"model": "openai/gpt-4o",
"messages": [
{"role": "system", "content": "You are concise."},
{"role": "user", "content": "Name three Rust crates for HTTP."},
],
}))
response = await client.chat(request)
print(response.choices[0].message.content)
asyncio.run(main())
Provider routing
The model string's prefix selects the provider; build a request per backend:
ChatCompletionRequest.from_json('{"model":"anthropic/claude-sonnet-4-20250514","messages":[...]}')
ChatCompletionRequest.from_json('{"model":"google/gemini-2.0-flash","messages":[...]}')
ChatCompletionRequest.from_json('{"model":"groq/llama3-70b","messages":[...]}')
ChatCompletionRequest.from_json('{"model":"mistral/mistral-large-latest","messages":[...]}')
ChatCompletionRequest.from_json('{"model":"bedrock/anthropic.claude-v2","messages":[...]}')
Set model_hint at construction to drop the prefix on every call:
client = create_client(api_key="sk-...", model_hint="openai")
# the request model can now omit the provider prefix:
request = ChatCompletionRequest.from_json('{"model":"gpt-4o","messages":[...]}')
await client.chat(request) # routes to OpenAI
Notes
- Keys come from env vars (
OPENAI_API_KEY,ANTHROPIC_API_KEY, …); never hardcode them. - Without a prefix and without
model_hint, routing fails. - Python errors are typed exceptions exported from
liter_llm:AuthenticationError,RateLimitedError,BadRequestError,ContextWindowExceededError,ContentPolicyError,NotFoundError,ServerError,ServiceUnavailableError,LiterLlmTimeoutError,BudgetExceededError— all subclasses ofLiterLlmError.