A PRD is supposed to answer one question for as long as the feature exists: why did we build this, and what were we trying to achieve? In practice, most PRDs answer that question for about a week. Then the doc goes stale, the reasoning drifts out of sync with what actually shipped, and the next person who needs the answer has to go find someone who remembers.
A living PRD is different by design. Instead of a document you write once and archive, it’s a record that keeps updating as new evidence arrives, as the underlying code changes, and as the shipped feature gets used in the real world. The document isn’t finished when it’s approved — approval is the point where it starts being useful.
Static PRDs were built for a slower product cycle
The traditional PRD format assumes a world where a feature gets scoped, built, shipped, and left alone for a while. That assumption doesn’t hold anymore. Product teams ship weekly, sometimes daily, and the reasoning behind a decision needs to survive many rounds of iteration — not just the first one. A document that can’t absorb new evidence without becoming a new document is quietly incomplete from day one.
What makes a PRD “living”
Three properties separate a living PRD from a static one:
It’s grounded in something that changes. A living PRD is tied to your actual codebase and your actual evidence stream — customer calls, tickets, usage data — not a snapshot of what someone believed on the day they wrote it.
It’s queryable, not just readable. Engineers, support, and sales should be able to ask it a question and get a grounded answer, the same way they’d query a database, instead of scanning a wall of prose for the one paragraph that matters to them.
It closes the loop. A living PRD doesn’t stop at “here’s what we’re building.” It stays open long enough to record whether the shipped result actually matched the intent — the step almost every team skips today.
Why this matters more in an AI-native engineering org
Coding agents like Claude Code and Cursor are only as good as the context they’re given. A stale PRD gives an agent yesterday’s understanding of a feature that may have changed twice since. A living PRD gives the agent — and the human reviewing its output — a source of truth that’s actually still true. That’s the real argument for treating product context the same way engineering teams have started treating specs: not a document you file away, but an asset that compounds.
This is the idea behind Argus. Every proposal is grounded in evidence and code, reviewed and merged rather than filed, and reshaped into different views for whoever needs to read it next — sales, support, or the engineer picking up the ticket. The document doesn’t reset every time someone asks “wait, why did we build this?” It just answers.