Full-Stack AI Engineer to drive Existing Codebase to Production-Ready MVP

I have an existing, partially built AI codebase. Before we expand it into a full end-to-end product, I need a senior engineer to run a surgical strike: audit the current foundation and execute our single most critical AI feature to prove the architecture works. I am not looking for a complete rebuild right now. I need someone who can drop into an unfamiliar repository, identify what is usable, and cleanly integrate one core feature without getting distracted by nice-to-haves. The Current State & Tech Stack: Existing Code: [e.g., Python FastAPI backend, basic prompt logic, early React frontend] The Target Feature: [e.g., Connect the RAG pipeline so it reliably parses uploaded PDFs and returns cited answers without hallucinating] The Project Milestones: Phase 1: Triage. Review the existing repository. Identify structural rot, security flaws, or technical debt that will prevent this specific feature from working. Phase 2: Execution. Ignore all secondary features. Focus entirely on making [Target Feature] function reliably and efficiently within the existing stack. Phase 3: Handoff. Push the working code and provide a concise, brutally honest summary of what needs to be refactored before we scale the rest of the application. Who You Are: You are fast, pragmatic, and highly experienced with production AI infrastructure (not just basic API calls). You are comfortable inheriting messy code and extracting value from it. You manage scope ruthlessly and know how to deliver a functioning Proof of Concept without over-engineering it. How to Apply: Generic cover letters will be instantly archived. To be considered, start your proposal with: The Reality Check: What is the biggest hidden risk when inheriting half-built AI code? Your Execution Plan: Give me a brief, bulleted breakdown of how you will tackle the three milestones above. Your Estimate: Based strictly on the scope above, what is your estimated timeline and fixed price to complete this micro-project?