calling-llms

name	calling-llms
description	Use when sending chat completions through liter-llm and routing to a specific provider via the `provider/model` prefix. Covers the chat call shape, provider routing, model_hint, message roles, and error categories.

Calling LLMs

Send a chat completion with client.chat(...). The model string is provider/model; the prefix selects the backend.

import asyncio, os
from liter_llm import LlmClient

async def main() -> None:
    client = LlmClient(api_key=os.environ["OPENAI_API_KEY"])
    response = await client.chat(
        model="openai/gpt-4o",
        messages=[
            {"role": "system", "content": "You are concise."},
            {"role": "user", "content": "Name three Rust crates for HTTP."},
        ],
    )
    print(response.choices[0].message.content)

asyncio.run(main())

Provider routing

await client.chat(model="anthropic/claude-sonnet-4-20250514", messages=[...])
await client.chat(model="google/gemini-2.0-flash", messages=[...])
await client.chat(model="groq/llama3-70b", messages=[...])
await client.chat(model="mistral/mistral-large-latest", messages=[...])
await client.chat(model="bedrock/anthropic.claude-v2", messages=[...])

Set model_hint at construction to drop the prefix on every call:

client = LlmClient(api_key="sk-...", model_hint="openai")
await client.chat(model="gpt-4o", messages=[...])  # 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.
• Errors share a category: Authentication, RateLimited, BadRequest, ContextWindowExceeded, ContentPolicy, NotFound, Server, ServiceUnavailable, Timeout, BudgetExceeded.