Stage 04 of 5 · PDLC: Design
What is the Design stage?
By Heemang Parmar · Updated July 2026
Design is the stage where the defined product becomes user flows, screen specifications, and a production-ready design system, so what gets built looks intentional rather than generated.
Design in a product pipeline is not decoration; it is the translation layer between requirements and code. When it is skipped or rushed, engineering improvises the interface and the product reads as generic.
In ProductOS, two agents share the stage. The Design Agent reads the concept, research, and PRD and produces user flows and screen specs for the product you actually defined. The Design System Agent builds the canonical tokens, components, and DESIGN.md brief from your locked brand, with real dark and light previews before any product code exists. Downstream code is built on those exact tokens.
Which agents run the Design stage?
How does the Design stage work?
- 1Brand locked: Palette, type, and direction are settled first, automatically or guided.
- 2System built: The Design System Agent produces tokens, components, and DESIGN.md with live previews.
- 3Flows and screens: The Design Agent specs the user flows and screens against the PRD.
- 4Handoff without loss: The Develop stage builds on the same tokens and specs, screen for screen.
What does the Design stage produce?
- User flows and per-screen specifications
- A design system: tokens, components, DESIGN.md
- Dark and light HTML previews of the system
Frequently asked questions
Can I bring my own brand?
Yes. Upload brand assets and lock your direction, and the design system is generated from it. If you have no brand yet, the pipeline generates palette, font pairing, and mood board options to choose from.
What stops the design from dying in handoff?
There is no handoff in the traditional sense. The coding agent reads the same design system tokens and screen specs the Design stage produced, so the shipped screens are the approved screens.