Principal Python + LangGraph Engineer

Engagement context

We are partnering with a US-based health-tech company on the takeover of a production AI-powered mobile coaching platform. The platform is built around a Python AI core (atlas-ai) which runs:

• A FastAPI chat surface with intent routing and tool-using agents
• A LangGraph-based agent framework with multi-agent orchestration
• A Celery + Redis task queue for asynchronous agent flows
• MongoDB for fitness-plan storage, Redis for conversation state, Postgres for LangGraph checkpoints
• Several agent personas: onboarding, chat, plan creation, in-workout smart adjust, plan smart adjust, habit formation
• Direct OpenAI integration for the LLM layer

This is the product. If the AI core breaks, the product breaks. If LLM token cost runs away, our margin runs away. If the agent flows behave unpredictably under load, real users get bad coaching.

Role summary

As Principal AI Engineer you are the technical owner of the AI core. You lead the audit of the existing codebase, define the architecture we evolve toward, build the test and evaluation harness that lets us ship changes safely, and you are the engineer who is paged when the AI surface misbehaves in production.

You will be the deciding voice on whether we can responsibly take this service in our scope or whether we keep the client's original team embedded longer. The audit conclusions you write in the first 4 weeks will inform the contractual scope of the entire engagement.

Offer:

• Location: 100% remote
• Engagement: B2B
• Rate: upt to PLN 180 p/h
• Start: asap