Research in.
A build-ready PRD out.
The Define stage writes a structured product requirements document section by section, grounded in your actual ideation and research, not a blank prompt. Outline approval gates every section before it is written.
The spec gap
Most products fail in the handoff between thinking and building
You have the research. The problem is clear, the users are profiled, the competitors are mapped. Now someone has to turn that into something the team can actually build from, scope that holds, stories that are testable, metrics that are measurable.
Most teams either skip the spec or write one that rots the moment the product changes. The Define stage closes that gap: it writes the PRD from your research and keeps it wired to everything downstream, so the spec stays the source of truth instead of a stale artifact.
What the Define stage produces
A PRD you could actually build from
Not a bulleted summary. A complete, structured requirements document with the parts that make a spec buildable rather than decorative.
Grounded in research, not a blank prompt
The PRD Agent reads the actual ideation concept and research brief before writing a single section. Every requirement traces back to evidence, not invention.
Outline approval before writing
You see the document structure before any section gets written. Approve the shape, then watch each section fill in against the research.
Targeted edits that do not rewrite the whole document
Revision mode updates specific sections without starting over. An approved spec stays approved except where you changed it.
Four templates for different situations
ProductOS Standard
The full document: problem, goals, scope, user stories, acceptance criteria, success metrics, roadmap, and open questions.
Amazon PRFAQ
Write the press release first. Stress-tests the narrative before committing to the spec.
Lean
Lightweight: problem, target user, three to five stories, and the one metric that proves it worked.
Enterprise and Regulated
A structured format for complex or regulated environments where requirements, constraints, and approvals need to be explicit.
Section by section, behind an approval gate
Research feeds in
The PRD Agent reads the ideation concept brief and the validated research brief before writing anything. Every requirement starts grounded.
Outline gets your approval
The agent scaffolds the document outline against the template you choose. You approve it before any section is written.
Sections written, one at a time
Each section is written in a single pass, against the outline and the upstream artifacts. You review and request changes before the next section starts.
Lock and hand off
When the document is approved, it becomes the source of truth for the Design stage. The Architect Agent can extend Define with system architecture if the build warrants it.
What lands in your project
PRD in your chosen template
ProductOS Standard, Amazon PRFAQ, Lean, or Enterprise and Regulated. Each is structured for a different level of narrative depth, speed, and requirement complexity.
Executive summary
A one-page synthesis of the problem, the proposed solution, target users, success metrics, and release scope.
User stories and acceptance criteria
Persona-linked stories with testable acceptance criteria per story, ready to hand to design and QA.
Scope, non-goals, and success metrics
Explicit in-scope and out-of-scope boundaries, measurable success metrics, and a phased roadmap.
Optional deep-dive
Extend Define with the Architect Agent
When the build warrants it, the Architect Agent produces real architecture documents from the locked PRD and your project constraints. It designs the system; it does not write the app code.
System overview
A container-level view of the system, its major responsibilities, and how data moves between them.
Database and API design
Entity-relationship models, API contracts, and authentication architecture from the PRD.
ADRs
Architecture decision records capturing every significant technical choice with context and consequences.
Infrastructure cost estimate
Projected running cost of the proposed architecture, so the build decision includes the full picture.
More than a blank-prompt PRD writer
A PRD that starts from evidence, not a blank page
A standalone prompt can produce a useful first draft. Define goes further by carrying the concept and research into an approval-gated document that remains available to downstream ProductOS agents.
A standalone prompt-first workflow
- Starts from the context supplied in the current prompt
- Produces a useful draft that still needs evidence and constraints added
- Document structure and revision workflow depend on how the user manages the conversation
- Downstream handoff requires sharing or recreating the document context
The Define stage in ProductOS
- Reads the ideation concept and research brief before writing
- Every requirement grounded in upstream artifacts
- Outline approval before writing; revision mode for targeted edits
- Approved output is live context for Design, Code, QA, and Review
Try the free lightweight PRD generator at /tools/prd-generator if you want a quick on-ramp without signing in. Define is the full stage inside ProductOS, built for teams who want a spec that is traceable all the way from research to shipped code.
Want a quick draft first? Try the free PRD generator
No sign-up required. Turn a short prompt into a solid lightweight PRD in seconds. Define inside ProductOS is the full version that reads your research and drives design and code.
Stage three of the pipeline
Define is where research becomes a decision
The approved PRD is not a document you file away. It becomes the shared context every downstream stage reads from, so screens and code stay traceable to the requirements.
Meet the PRD Agent
See the full agent page: the requirements writer that works from your research, not a blank prompt.
Define stage
See how stage three turns research into an approved PRD before design and code begin.
Research product
Jump straight into Define once your research brief is ready.
Design product
The Design stage reads the approved PRD and produces flows, screens, and a design system.
Code product
The Code Agent implements against the approved requirements and the designs produced from them.
Frequently asked questions
Which PRD template should I use?
ProductOS Standard fits most products. Amazon PRFAQ works when you want to pressure-test the narrative first. Lean when speed matters more than completeness. Enterprise when compliance or regulated requirements apply.
Can I edit the PRD after it is approved?
Yes. Revision mode makes targeted edits to specific sections instead of rewriting the document, so an approved spec stays approved except where you changed it.
What does the optional Architect Agent produce?
From the locked PRD and your constraints, the Architect Agent produces system overview, database and API design, deployment and security architecture, ADRs, and infrastructure cost estimates. It designs the system; it does not write the app code.
How is Define different from the free PRD generator at /tools/prd-generator?
The free tool produces a lightweight PRD from a short prompt, no sign-up required. Define is the full ProductOS stage: it reads your actual ideation concept and research evidence, uses outline-approval gating, writes section by section, and its approved output becomes live context for Design, Code, QA, and Review.
Does the PRD feed into the rest of the pipeline?
Yes. The approved PRD becomes shared context for the Design stage: the Design Agent reads it for flows and screens, the Code Agent reads it for implementation, and the QA Agent reads its acceptance criteria. Targeted revisions help the specification evolve without rewriting the whole document.
Write a spec that actually gets built
Turn your research into a build-ready PRD with scope, user stories, and success metrics. Then let the Design and Code stages build straight from it.