Agent Architect

About the role

Pencil is building an agentic operating system for marketing, leveraging generative AI to power creative content for brands of all sizes. As an Agent Architect you will design the core "brain" of the platform, creating robust multi‑agent workflows that translate creative intent into high‑fidelity text, image and video outputs.

Key responsibilities

• Design and implement multi‑agent workflows, including task decomposition, state management and tool‑use (RAG, API integration, etc.).
• Develop rigorous evaluation frameworks (LLM‑as‑a‑judge, promptfoo, DSPy) to measure and improve agent performance at scale.
• Create reusable agents and prompt libraries that enable the platform to serve thousands of brands simultaneously.
• Lead discovery sessions with brand and agency stakeholders, translate vague briefs into scoped technical solutions, and present trade‑offs in plain language.

Required profile

• 3+ years of direct generative AI experience with large language models (GPT‑4, Claude, Gemini) and multimodal models (Stable Diffusion, Midjourney, video generation).
• Systems‑thinking mindset, comfortable with Python, JSON and API documentation.
• Strong evaluation obsession: familiar with benchmarking, A/B testing and automated evaluation of AI outputs.
• Proven ability to communicate technical concepts to non‑technical clients and act as the technical lead on complex deployments.

Required skills

• Python
• JSON
• API integration
• LLM prompt engineering (GPT‑4, Claude, Gemini)
• Multimodal model experience (Stable Diffusion, Midjourney, video generation)
• Evaluation tools (promptfoo, DSPy)

What we offer

• 25 days PTO plus public holidays with a flexible time‑off scheme
• Health insurance / private medical cover
• Monthly stipend for wellness, fitness and learning
• Remote work from anywhere in your home country
• Enhanced parental leave policies
• Access to Pencil office in The Shard, London for UK employees
• Flexible working hours