Senior Core AI Engineer

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/ $100 - $125 hour

INFO

Salary
SALARY:

$100 - $125

Location

LOCATION

Job Type
JOB TYPE

Contract

Senior Core AI Engineer: LLMs & Agentic Systems (Contract, On-site NYC)

About Harnham
Harnham specializes in data, AI, and analytics recruitment, partnering with cutting-edge teams turning LLMs and agentic systems into real products.

About the Client
Our client is a fast-moving AI startup based in New York City. They are building agentic AI products in a space with significant upside and a clear path to a future exit. The environment is highly technical, founder-led, and focused on shipping impactful systems quickly.

Role Details
  • Title: Senior Core AI Engineer: LLMs & Agentic Systems
  • Type: Contract (short term, with strong likelihood of extension or conversion to full-time)
  • Duration: Roughly 3 months (initial contract)
  • Location: New York City, hybrid
  • On-site expectation: 3-4 days per week
  • Hours: 40 hours per week
  • Start: ASAP
  • Pay Range: $100-$125/hr
The Role
This role is for a senior engineer who lives and breathes AI and wants to design and build agentic systems on top of LLMs. You will focus on core AI and system design: experimenting, iterating, and pushing from 0 to 1 on new workflows. While there is a path into production, this role leans toward experimentation, R&D, and systems-level thinking rather than pure infra. You will work closely with founders, may interact with clients, and need to communicate clearly in a fast-changing environment.

Key Responsibilities
  • Design, prototype, and refine agentic systems using large language models to automate complex, multi-step workflows.
  • Run experiments across prompts, architectures, and tool integrations to improve reliability and performance.
  • Work at the systems level: reason about the entire agent loop (planning, tools, memory, feedback), not just the model.
  • Collaborate with MLOps and platform engineers to ensure designs can be productionized and operated reliably.
  • Use AI-assisted tools (GitHub Copilot, Cursor, Claude, etc.) to accelerate experimentation and implementation.
  • Communicate clearly with founders and stakeholders about tradeoffs, limitations, and progress.
Requirements: Must Have
  • Strong experience with core AI and NLP, especially large language models and agentic or tool-using systems.
  • Demonstrated ability to take AI ideas from 0 to 1: research, prototype, iterate, and influence product direction.
  • Solid Python skills and comfort building experimental yet clean, maintainable code.
  • Systems-level thinking: understands orchestration, context, tools, and evaluation loops, not just individual model calls.
  • Excellent communication skills and ability to be client- or stakeholder-facing when needed.
  • Willingness and ability to work on-site in NYC 3-4 days per week in a fast-moving, changing environment.
Nice to Have
  • Prior experience in a startup or founder-led environment.
  • Background in research or advanced experimentation with LLMs, agents, or related frameworks.
  • Experience with popular agent / LLM frameworks (LangChain, LlamaIndex, tool calling / function calling setups).
  • Familiarity with AI-related hardware or accelerators (beneficial but not required).
  • Proven use of AI tools in your own engineering workflow.

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