interview-prep-feature

Interview Prep Feature

Static on-demand guide on the Interview tab (process / questions / preparation). Not the timed conversational Mock Session tab — see mock-interview-feature.mdc.

Standalone Agent (NOT in LangGraph workflow)

InterviewPrepAgent in agents/interview_prep.py is invoked on-demand, independently of the main 5-agent LangGraph workflow. It is called from api/interview_prep.py via BackgroundTasks.

agent = InterviewPrepAgent()
result = await agent.generate(
    job_analysis=workflow_session.job_analysis or {},
    company_research=workflow_session.company_research or {},
    profile_matching=workflow_session.profile_matching or {},
    user_profile=workflow_session.user_data or {},
    user_api_key=user_api_key,  # BYOK
)

Background Generation with Atomic Redis Locking

Use the Redis lock to prevent duplicate concurrent generations:

from utils.cache import (
    is_interview_prep_generating,
    set_interview_prep_generating,   # Returns False if already locked
    clear_interview_prep_generating,
    cache_interview_prep,
    invalidate_interview_prep,
)

# Atomically claim the slot (NX SET)
claimed = await set_interview_prep_generating(session_id)
if not claimed:
    raise APIError(ErrorCode.RES_3001, "Interview prep generation already in progress", status_code=409)

# Always pass user_id so WebSocket broadcasts work inside the background task
background_tasks.add_task(_generate_background, session_id=session_id, user_id=str(user_id), ...)

Always clear the lock in finally and broadcast lifecycle events:

from api.websocket import (
    broadcast_interview_prep_started,
    broadcast_interview_prep_complete,
    broadcast_interview_prep_error,
)

async def _generate_background(
    session_id: str,
    user_id: Optional[str] = None,
    user_api_key: Optional[str] = None,
):
    try:
        async with get_session() as db:
            workflow_session = await _load_session(db, session_id)
            ws_user_id = user_id or str(workflow_session.user_id)

            await broadcast_interview_prep_started(ws_user_id, session_id)

            # generate and save
            workflow_session.interview_prep = result
            flag_modified(workflow_session, "interview_prep")
            await db.commit()
            await cache_interview_prep(session_id, result)

            await broadcast_interview_prep_complete(ws_user_id, session_id)
    except Exception as e:
        logger.error(f"Interview prep failed: {e}", exc_info=True)
        await broadcast_interview_prep_error(ws_user_id, session_id, "Interview prep generation failed")
    finally:
        await clear_interview_prep_generating(session_id)