Instructor

pip install instructor openai pydantic

import os
from pydantic import BaseModel, Field
from openai import OpenAI
import instructor

# Initialize patched OpenAI client targeting nRouter
client = instructor.from_openai(
    OpenAI(
        base_url="https://api.nrouter.ai/v1",
        api_key=os.environ["NROUTER_API_KEY"],
    )
)

class UserProfile(BaseModel):
    name: str
    skills: list[str] = Field(description="Core technical capabilities")
    experience_level: str = Field(description="Junior, Mid, Senior, or Staff")

response = client.chat.completions.create(
    model="gpt-5.4-mini",
    response_model=UserProfile,
    max_completion_tokens=1024,
    messages=[
        {
            "role": "user",
            "content": "Jason has 8 years of experience building distributed systems in Rust and Go.",
        }
    ],
)

print(response.name)              # Jason
print(response.experience_level)  # Senior
print(response.skills)            # ['Rust', 'Go', 'distributed systems']