RYAN ZERNACH

Full-Stack AI Systems Engineer

Ryan_Zernach_2025_Senior_AI_Systems_Engineer_Remote_United_States

🧭 AI Engineering Methodologies

AI changed software engineering twice: it reshaped how we deliver code, and it expanded what software itself can do. In the delivery loop, plans beat vibes, skills beat one-off prompts, and verification beats blind trust. In the product, retrieval, graphs, agents, evals, observability, and MCP are now part of the surface area. My work lives at that seam: directing AI inside the delivery loop while architecting it into the product.

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AI engineering methodologies featured image covering RAG, agents, graphs, embeddings, evaluations, and LLM ops

Summary

This is the discipline I use to ship AI-native products without turning the codebase into a slot machine. It combines clear task decomposition, reusable skills, hard verification, and an architecture-level understanding of modern AI systems.

The Shift

Software engineers used to spend more of the day performing every line. Now we direct more of the production: brief agents, set guardrails, review the takes, and decide what earns a merge.

Premium Positioning

That is why "AI is the engineer and I am the tool" is intentionally provocative. The human does not disappear; the role moves upstream into system design, editing, evaluation, and accountable ownership.

The Areas That Matter

A premium AI engineer needs range, but not random range. The work clusters into a small number of capabilities that compound together. Coding with AI, verification, RAG, agents, evals, and product sense are the visible pillars. MCP and observability are the connective tissue that make the whole system real.

  • Coding with AI: methodology, plan mode, skills, and task decomposition
  • Verification: how you review and own AI output before it ships
  • RAG: architecture, chunking, retrieval quality, and failure modes
  • Agents: tool use, failure handling, guardrails, and controlled autonomy
  • Evals: datasets, scorecards, and release gates
  • Product Sense: tradeoffs, prioritization, and communication
  • MCP + Observability: the operational backbone underneath the product

Track 1: Coding With AI

Prompting is only the front door. The real work is a methodology that turns AI-assisted speed into trustworthy software: repeatable, reviewable, and still owned by the engineer who ships it.

Methodology over prompt roulette

Greenfield and brownfield are different sports

Tasks, tickets, and MCP-connected systems

Skills are reusable operating procedures

This is where the methodology gets durable

Verification is the separator

The Stack: Three AI Coding Assistants In Parallel

Methodology only matters if it runs on real tools. I pay for Codex, Cursor, and Claude on purpose, and I deliberately run all three so I never feel reliant on any single assistant, model family, or vendor. If one regresses, throttles, or goes down, my workflow does not. Codex is my current go-to for the bulk of execution, but Cursor and Claude are always one keystroke away, and the job of the human director is to assign each task to the assistant best suited for it and then own the merge.

Codex, Cursor, and Claude app icons side by side

Codex

My current go-to for bounded, async execution

Cursor

IDE-native agent, Composer model, rules, skills, MCP

Claude

Reasoning, planning, long-context investigation

Track 2: Building With AI

The second track is product architecture. Here the question is not how I use AI to code faster, but how I make it useful inside a product without asking users to trust a mystery. RAG, graphs, agents, and evals are the visible pillars. MCP, observability, and product sense make them dependable in the real world.

RAG

Chunking, embeddings, retrieval quality, failure modes

Graphs

When structured relationships beat flat retrieval

Agents

Tool use, multi-step reasoning, guardrails

Evals

Where most candidates fail. The separator.

MCP

How the model reaches real systems

Observability

What the model saw, did, cost, and broke

Product Sense

Tradeoffs, prioritization, comms

AI Engineering Topics

These are the conversations that separate someone who has merely used AI tooling from someone who can architect, instrument, debug, and ship serious AI systems under real business constraints.

Explain RAG to me like I am an engineer who has never implemented it. Then tell me its failure modes.

When would you use a graph-based retrieval approach over a vector store?

Walk me through designing an agent that does not go off the rails.

What is the difference between LangSmith and LangFuse? Which would you use?

How do you build an eval set from scratch? Where does the data come from?

What does observability mean in an LLM application?

How do you run a prompt experiment without breaking production?

What is the hardest debugging problem you have encountered in an AI application?

What Premium Looks Like

Premium AI engineering is not maximum hype. It is the ability to move fast without turning the system into a black box, to use agents without surrendering standards, and to explain the architecture in plain English to both technical and non-technical stakeholders.

Why Hire Me For This

I sit at the intersection of product sense, full-stack shipping, and AI systems thinking. I can run AI inside the development loop and build AI into the product loop. That combination is commercially useful, technically rare, and exactly where the market is heading.