Write PRD

Produce docs/specs/<feature-slug>/_prd.md — the product definition the rest of the pipeline (write-techspec, write-tasks, implement-task, qa-gate) implements from. The PRD owns what and why; the tech spec owns how. Keeping that boundary is what lets each artifact stay small and stay true while the code changes underneath it.

Inputs

$ARGUMENTS is a feature description, or empty when the current conversation already explored the feature (a grilling or brainstorm session). Everything already answered in the conversation counts as answered — do not re-interview.

If docs/specs/<slug>/_idea.md exists (produced by write-idea), it is the exploration: read it first, and treat its research, scoring, trade-off insights, chosen direction, and Out of Scope list as answered ground truth. Clarify only what the idea left open.

Size triage first

Not every change earns a PRD — it pays for itself when there are product decisions to record and multiple tasks to derive. If the work changes no product behavior (a refactor, a bug fix), say so and route to write-techspec, which enters the pipeline directly and mints the spec folder with a minimal _prd.md. If the change is trivial (one-line fix, typo, config tweak), recommend direct implementation with no spec folder.

Ground rules

• Read CONTEXT.md and docs/adr/ before anything else. Use the glossary's vocabulary throughout — titles, user stories, feature names — and never drift to synonyms the glossary lists under _Avoid_. If a concept has no term yet, sharpen one with the user and add it to the glossary right then; a PRD written in fuzzy language produces fuzzy tasks. If either file is missing, proceed silently.
• Decide, then write. Once research and clarifications are done, write the file directly and let the user react to the finished artifact. Do not present outline drafts for approval — reviewing a real PRD is faster than reviewing a promise of one.
• Durability. No file paths, no code snippets, no line numbers, except the mandatory docs/agents/ Project Constraint sources and exact files covered by tooling authorization. The PRD may sit in a queue for weeks while the codebase moves; describe behavior and interfaces, which survive refactors.