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Pencil uses AI to make ads. Our mission is to make marketing effective and effortless. We want to become the default way ads get made — because AI ads are 10x faster and cheaper to make, and 2x better performing, than making them without AI. Pencil was founded in 2018 with a team from Google, Facebook and Uber with backing from Sequoia and Entrepreneur First. We were acquired by The Brandtech Group in 2023 to pursue a shared vision of bringing GenAI to the Fortune 500.
Prompt Engineer
Location
United States
Posted
99 days ago
Salary
0
Seniority
Mid Level
No structured requirement data.
Job Description
Prompt Engineer
Pencil
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: - Core Systems: Designing and scaling the foundational agents that power the Pencil SaaS platform. - 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.
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