Senior AI Agent Designer: Shape Pro-Grade Assistants

Topline Pro; Boston; On-site; PHP 7,658,000 - 11,487,000; Full time

Benefits offered by this job

YC-backed

Job summary

Topline Pro is looking for a lead designer to become the first dedicated to Sidekick Labs, shaping how Sidekick thinks, behaves, and presents itself across apps and partner surfaces. You will define prompts, rubrics, and system rules, and ensure the agent’s work is trustable and transparent.

You will report to the VP of Design and collaborate with the Head of App Experience, Sidekick Labs engineers, and the product manager to audit, pattern, and scale agent design across ten products.

Qualifications

• 6+ years of product design experience with a strong shipped portfolio.
• 2+ years designing LLM-powered products live with real users (agents, assistants, copilots).
• Experience writing prompts and system instructions that shipped.
• Ability to read traces, identify where an agent went wrong, and explain why.
• Think in systems; design patterns that scale across multiple agents.
• Clear, plain copy is central to product in agent products.
• Experience researching with non-tech users and adapting to their workflows.
• Prototype in code (HTML, CSS, JS, or React Native) with AI tooling.
• Stay close to model capabilities and design for future limits and opportunities.
• Strong craft; UI that is polished and trusted.
• Experience delivering complex products end to end in undefined spaces.
• Thrives in small, fast teams with evolving problems.

Responsibilities

• Define the target Sidekick behavior, tone, and decision points across products.
• Audit current Sidekick usage and set patterns for cross-platform consistency.
• Design prompts and system rules that govern agent actions and error handling.
• Show work and explain reasoning to pros through transparent outputs.
• Design waiting experiences for complex requests to feel fast and controlled.
• Create discoverability patterns that teach pros about Sidekick capabilities.

Skills

Product design

LLM-powered products

Prompt engineering

Trace analysis

Systems thinking

Clear writing

Prototype coding

React Native

Claude Code

Tools

Claude Code

Job description

Topline Pro is looking for a lead designer to become the first dedicated to Sidekick Labs, shaping how Sidekick thinks, behaves, and presents itself across apps and partner surfaces. You will define prompts, rubrics, and system rules, and ensure the agent’s work is trustable and transparent.

You will report to the VP of Design and collaborate with the Head of App Experience, Sidekick Labs engineers, and the product manager to audit, pattern, and scale agent design across ten products.