Designing for AI Suggestions: UX Decisions Behind SynthStyle's Prompt Composer

AI · 5 min read

SynthStyle, a generative design tool, introduced an inline suggestion bar that proposes stylistic modifiers and constraints as users typed prompts. Early iterations were either too intrusive or too hidden, causing frustration or low discoverability. The design team adopted a lightweight card pattern with clear affordances for accepting, editing, or dismissing suggestions without breaking the user's typing flow.

Key design decisions included limiting suggestions to three at a time, adding a subtle predictive confidence meter, and deferring heavy model suggestions until the user stopped typing for 450ms. The team also added explainability snippets that displayed why a modifier was suggested and which dataset it referenced. To address privacy concerns, the UI offered a local-only suggestion mode for teams handling sensitive IP.

A randomized experiment showed that users who had access to inline suggestions completed high-quality prompts 31% faster and generated assets that reviewers rated as more on-target 18% of the time. However, engagement varied by experience level: novices relied heavily on suggestions, while experts mostly used them as inspiration. SynthStyle made the suggestion bar fully dismissible and added preference controls so users could tune AI assistance to their workflow.