At Pencil, we’re building the agentic OS for marketing. We aren't just using integrating generative AI; we are building the machine that makes it professional, brand-safe, and scalable. We’re moving beyond simple text-in/text-out interfaces toward complex multi-agent architectures that can handle the nuanced demands of global brands and the agility of small businesses.

We are looking for a Prompt Engineer who thinks in systems, not just sentences. You will be responsible for the "brain" of Pencil—designing the agent logic, tool-calling structures, and evaluation loops that power our core creative engine and bespoke client solutions.

The Role: Architecting the Creative Brain:

You won’t just be "prompting"; you will be engineering behavior. You will bridge the gap between creative intent and machine execution, ensuring that our agents are robust, predictable, and capable of high-fidelity output across text, image, and video.

Your work will fall into two high-impact pillars:

1. Core Systems: Designing and scaling the foundational agents that power the Pencil SaaS platform.

2. Client Solutions: Architecting custom workflows for world-class brands that require specific "brand DNA" and complex creative logic.

• 3+ Years of Direct GenAI Experience: You have a deep, intuitive, and technical understanding of LLMs (GPT-4, Claude, Gemini) and multimodal models (Stable Diffusion, Midjourney, Video Gen).

• Systems Thinking: You don’t just write a prompt; you think about the latent space, the context window, and how one agent's output becomes another’s input.

• Technical Literacy: While this isn't a "Software Engineer" role, you should be comfortable with Python, JSON structures, and API documentation. Experience with orchestration frameworks (LangChain, CrewAI, AutoGen) is a major plus.

• Evaluation Obsession: You believe that if you can’t measure a prompt’s performance, you shouldn’t ship it. You are familiar with benchmarking and A/B testing AI outputs.

• The "Creative/Technical" Bridge: You can sit in a room with a Creative Director and translate "make it feel more punchy" into a temperature adjustment and a few-shot prompting strategy.

You’ll Thrive Here If...

• You find "hallucinations" to be a logic puzzle to be solved, not just a bug.

• You are excited by the challenge of making an AI follow a 50-page brand book with 100% fidelity.

• You want to build the infrastructure that defines how the next generation of advertising is created.

• Design and refine prompts, workflows, and AI agents that enable clients to generate high-quality creative outputs at scale.

• Collaborate with the Delivery teams to understand client goals and translate them into prompt-based solutions.

• Build reusable prompt frameworks and templates for recurring use cases.

• Test, evaluate, and iterate on prompts and agents to improve output quality, efficiency, and user satisfaction.

• Define and document best practices for prompt creation, testing, and deployment within Pencil’s platform.

• Partner with Product and Engineering teams to identify new capabilities or improvements based on client feedback.

• Contribute to internal playbooks, demos, and guides that showcase how to get the most out of our agents and AI tools.

KPIs & Success Measures

• Agent adoption rate: Growth in the number of active clients using Pencil-built agents and workflows.

• Creative generation volume: Increase in the number of generations produced through agents you’ve developed.

• Output quality: Improvement in client satisfaction scores or internal quality benchmarks.

• Efficiency: Reduction in time-to-first-output or manual setup time for client projects.

• Knowledge sharing: Contributions to prompt libraries, playbooks, and team enablement materials.

• 25 days PTO plus public holidays, although we operate a Flexible Time Off scheme.

• Health insurance / private medical cover.

• Monthly stipend towards wellness, fitness, and learning and development.

• Remote - work from anywhere in your home country.

• Enhanced parental leave policies, whether you become a parent through birth, adoption or surrogacy.

• Access to our Pencil office in The Shard, London for our UK employees.

• Flexible working hours.