app/services/llm_service.py

from openai import OpenAI

from app.core.settings import settings


class LLMService:

    def __init__(self):

        self.client = OpenAI(
            api_key=settings.openrouter_api_key,
            base_url="https://openrouter.ai/api/v1",
        )

    def chat(
        self,
        question: str,
        context: str,
    ) -> str:

        prompt = self._build_prompt(
            question,
            context,
        )

        response = self.client.chat.completions.create(
            model=settings.llm_model,
            temperature=0.2,
            messages=[
                {
                    "role": "system",
                    "content": (
                        "You are an expert software engineer. "
                        "Answer only using the provided repository context."
                    ),
                },
                {
                    "role": "user",
                    "content": prompt,
                },
            ],
        )

        return response.choices[0].message.content

    def _build_prompt(
        self,
        question: str,
        context: str,
    ) -> str:

        return f"""
Repository Context
==================

{context}

==================

Question:
{question}

Instructions:

- Answer only using the repository context.
- If the answer cannot be inferred from the context, say so.
- Be concise.
- Mention function and class names using their qualified names.
"""