How do you keep your GDD in sync with the actual game project?

Hi everyone,

I’m an indie developer working with a small team (3 – 5 people) on a Unity project, and I’m struggling with a familiar problem: our Game Design Document (GDD) is always one sprint behind the actual game.

When a prototype feature evolves—or gets cut—the GDD quickly drifts out of date. After a few weeks it’s hard to tell which source of truth to trust, so nobody ends up trusting either.

What I’d love to learn from you

• Workflow
  Do you treat the GDD as a “living” document that you edit every time the build changes, or do you snapshot it at milestones and write separate patch notes?

• Tools & integrations
  Which platforms make this easiest?

  • Confluence / Notion with embedded diagrams
  • Google Docs tied to task‑tracking
  • Markdown in the repo alongside source code
  • Something else entirely?

• Version control
  Do you branch your GDD the same way you branch code/art, or keep it on a single doc and rely on history/track‑changes?

• Ownership & discipline
  Who is responsible for updating the doc?
  Do you assign a “lore keeper,” or make it part of the Definition of Done for each ticket?

• Granularity
  How detailed is your GDD once production is in full swing?
  Do you maintain high‑level pillars only, or keep minute‑by‑minute combat numbers there too?

• Success (and horror) stories
  Any anecdotes where a well‑maintained (or completely stale) GDD saved—or nearly sunk—your project would be super valuable.

What we’ve tried so far

• Single Notion page with headers for mechanics, UX, balancing tables
  Pros: easy linking Cons: everyone forgets to update
• Google Drive folder full of feature sheets
  Pros: simple Cons: no cross‑doc linking, hard to search
• Markdown in Git repo alongside scripts
  Pros: diffable, PR reviews Cons: designers less comfortable with Git

None of these have stuck yet, so I’m open to new ideas or stricter habits.

Thanks in advance for any advice, templates, or horror stories you can share!
If you have a public example (even an anonymized one), I’d love to see how you structure it.