The Ultimate Guide to TTRPG Session Prep with AI

•Urdr Team

The "Matt Mercer Effect" has set an impossible standard for Game Masters. We feel like we need fully painted minis, professional voice acting, and Tolkien-level lore for every session.

The reality? Most DMs burn out because prep takes too long.

AI tools are changing the game. Not by replacing the DM, but by acting as a co-pilot. Here is how to cut your prep time in half.

1. The "Lazy DM" Approach + AI

Sly Flourish's Return of the Lazy Dungeon Master teaches us to prep only what we need. AI is the perfect tool for this.

Instead of writing a 10-page history of a town the players might skip, generate 3 bullet points:

  1. Name & Vibe: "Grimhollow, a misty mining town."
  2. The Problem: "Miners are disappearing in the deep shafts."
  3. The Secret: "They aren't dying; they are being recruited by a subterranean cult."

Urdr Workflow: Type "Mining town with a dark secret" into Urdr's generator. In 30 seconds, you have the town (Location), the mine (Location), and the cult (Group).

2. Infinite NPC Generator

Players love to talk to the random goblin you didn't name.

  • Old Way: Panic, name him "Boblin," stare blankly.
  • AI Way: Generate a list of 10 generic NPCs before the session.
    • Name: Krog
    • Quirk: Collects shiny rocks.
    • Secret: Knows a back entrance to the villain's lair.

3. Loot and Rewards

Generic loot is boring. "You find 50 gold" is forgettable.

Ask AI for "flavorful loot for a level 3 party in a swamp dungeon":

  • The Bog-Witch's Ladle: Turns water into muddy soup (sustains 1 person/day).
  • Frog-Leather Boots: Advantage on stealth checks in wetlands.

4. Consistency Checks (The Urdr Special)

The hardest part of long campaigns is remembering what you said 6 months ago.

  • "Wait, didn't the innkeeper say the King was dead?"
  • "No, that was the Duke."

Urdr's Consistency Engine remembers. When you add a new event, it checks against your existing lore. If you try to say the King is alive when you previously wrote he died, it flags the contradiction.

5. Improvisation Support

Keep your AI tool open during the session.

  • Player: "I want to forage for herbs."
  • DM (typing): "List 3 fantasy herbs found in a cursed forest."
  • AI: "Bloodroot, Ghost-fern, Widow's Weep."

Conclusion

AI doesn't kill creativity; it unblocks it. By offloading the grunt work—names, stats, basic descriptions—you free up your brain to focus on the story, the acting, and the players' reactions.

Prep smarter. Play more.

The Real Long-Campaign Win: Continuity

Prep speed is great, but long campaigns die from continuity drift:

  • NPC facts changing between sessions
  • factions gaining/losing power without explanation
  • timelines and travel times breaking

That’s why a structured world bible matters — and why “Lore CI” (consistency checks for canon) is such a powerful mental model.

Read next: Lore CI: Treat Your World Bible Like Code

Next Step

  • Build a campaign world as structured entities: Create a world
  • See what Urdr is shipping (continuity + structured data): Features