I Ran a Zero-Prep D&D Session Using Only AI (Here's Exactly How)

The Experiment That Shouldn't Have Worked

It was 2:47 PM last Saturday. Session starts at 3:00 PM.

I'd had a brutal week at work. Between debugging our Discord bot's voice recognition and handling a production database issue, I'd completely forgotten to prep. My players were already on their way over.

Normally, this would be panic time. Cancel the session? Run a one-shot? Fake a sudden illness?

Instead, I decided to run an experiment I'd been thinking about for months: Could AI really handle an entire session with zero traditional prep?

Not "light prep." Not "I'll just wing it." Absolutely zero preparation beyond knowing where we left off.

The Setup: My Zero-Prep Toolkit

Here's exactly what I had when players arrived:

Hardware:

• Laptop with ChatGPT Plus open

• Second monitor for Discord (we use StormScape's bot for music)

• Phone with name generator app (backup)

Digital Tools:

• Our campaign notes in StormScape (previous session summaries)

• ChatGPT in one tab

• Dice roller in another

• StormScape for ambiance

Physical Tools:

• Blank paper for tracking initiative

• Dry erase mat (no pre-drawn maps)

• Standard dice

Preparation Time: Literally zero minutes

The Minute-by-Minute Breakdown

3:00 PM - The Cold Open

Players sit down. I have nothing. Time for the first prompt:

PROMPT #1 - The Session Starter:

I'm DMing D&D right now. The party (paladin, rogue, wizard, ranger) 
ended last session discovering the duke's advisor is a shapeshifter.
They're in the castle guest quarters at dawn.

Give me a dramatic cold open that starts with immediate action or decision. 
Include sensory details. 30 seconds to read aloud.

ChatGPT's Response (used verbatim): "You're awakened by screaming from the courtyard below. Through your window, you see castle guards surrounding something in the pre-dawn gloom. The acrid smell of smoke drifts up. The duke's advisor—the one you discovered is a shapeshifter—stands at the center, holding a torch over what appears to be a pile of documents. 'Traitors!' he shouts. 'Burn the evidence of their treachery!' A guard looks up, sees you watching, and points. 'There! The conspirators are awake!'"

Player Reaction: Immediate engagement. The rogue is already planning escape routes.

3:05 PM - The Unexpected Question

Paladin: "What documents is he burning? Can I see them from here?"

I have no idea. Time for prompt #2:

PROMPT #2 - The Detail Generator:

The documents being burned are evidence. What would a corrupt advisor 
burn to frame the party? Make it something that creates a moral dilemma.
Give me 3 specific documents they can partially see.

Result: Letters "proving" the party was selling military secrets, but one document has the seal of an orphanage the paladin donated to last session.

Player Reaction: "Oh shit, he's using our good deeds against us!"

3:15 PM - The Combat That Wasn't

The party decides to confront the advisor publicly instead of fighting. I didn't expect this.

PROMPT #3 - The Social Encounter:

The party wants to publicly challenge the shapeshifter advisor in front 
of the crowd. He's trying to frame them. How would he respond to maintain 
his cover? Give me his arguments and 3 pieces of "evidence" he'd present.
Make him convincing but leave logical flaws the players can exploit.

This turned into a 30-minute social encounter with accusations, counter-evidence, and the wizard using Detect Thoughts at the perfect moment.

3:45 PM - The Plot Twist I Didn't Plan

Ranger: "Wait, if he's a shapeshifter, who is he replacing? Where's the real advisor?"

I have literally no idea. This wasn't planned. Prompt time:

PROMPT #4 - The Plot Development:

Plot twist: The shapeshifter replaced the duke's advisor. 
Where is the real advisor? Give me three possibilities:
1. Dark option
2. Compelling option  
3. Unexpected option

For the compelling option, explain how discovering this would change everything.

The Result: The real advisor is alive, imprisoned in his own mind while the shapeshifter uses his body. He's been conscious the whole time, screaming silently for months.

Player Reaction: Dead silence, then "That's genuinely horrifying. We have to save him."

This became the session's main quest.

4:15 PM - The Dungeon That Didn't Exist

Players track the shapeshifter to hidden chambers beneath the castle. I need a dungeon RIGHT NOW.

PROMPT #5 - The Instant Dungeon:

Create a 5-room dungeon beneath a castle. Theme: magical imprisonment.
Room 1: Entrance challenge
Room 2: Trap or puzzle
Room 3: Combat encounter
Room 4: Moral choice
Room 5: Boss confrontation

For each room: one sentence description, one interesting feature, one decision point.
Keep it theater of the mind friendly.

4:45 PM - The NPC Nobody Expected

In the dungeon, players find prisoners. The rogue asks to talk to one.

PROMPT #6 - The Emergency NPC:

Quick! Generate a prisoner NPC:
- Why they're imprisoned
- One distinctive trait
- What they want from the party
- A secret that matters
Make them memorable in 3 sentences.

Result: "Jasper Three-Coins," a halfling who claims he's imprisoned for stealing bread but actually discovered the duke's son is also a shapeshifter. Speaks only in questions.

This NPC became crucial to the story.

5:30 PM - The Combat Encounter

Finally, combat with the shapeshifter. I need tactics, personality, and phases.

PROMPT #7 - The Boss Fight:

Shapeshifter boss fight, level 6 party of 4.
Give me:
- 3 forms it shifts between (with different tactics)
- Environmental hazards in the room
- What it says while fighting
- Victory and defeat conditions
- One unexpected twist mid-fight

The fight was dynamic, with form shifts based on damage thresholds and the twist that killing the shapeshifter might kill the real advisor too.

6:15 PM - The Emotional Climax

Players must decide: Kill the shapeshifter and the innocent advisor, or find another way?

PROMPT #8 - The Resolution:

Players want to separate shapeshifter from host without killing either.
Give me three possible solutions:
- Magical approach
- Emotional approach  
- Clever trick approach

Include consequences for each.

Players combined approaches, with the paladin appealing to the real advisor's consciousness while the wizard performed a risky ritual.

6:45 PM - The Cliffhanger

Session needs to end with a hook for next time.

PROMPT #9 - The Cliffhanger:

Session ending cliffhanger. They saved the advisor who revealed 
the duke's son is also replaced. What does he say that makes this urgent 
but also personal to one of the party members? Make it a one-line revelation.

Result: "The wedding is in three days, and your sister is the bride."

Player Reaction: "WHAT?! My sister?! We're playing next week, right?!"

What Actually Worked (Surprising Results)

1. Consistency Was Better Than Expected

AI remembered details within the session better than I usually do. When players referenced the burning documents from hour 1 in hour 4, I could quickly prompt: "Earlier, documents were burned including orphanage seal. What would the advisor reveal about those documents now?"

2. Player Agency Increased

Without prep, I couldn't railroad. Every player decision genuinely shaped the story. They noticed:

• "This feels more responsive than usual"

• "It's like the world is actually reacting to us"

3. Descriptions Were More Vivid

AI generates sensory details I often forget:

• Smells, sounds, temperatures

• NPC body language

• Environmental atmosphere

4. Pacing Improved

No prep meant no attachment to unused content. Scenes ended naturally, not because I needed to get to my prepared content.

What Failed (And How I Fixed It)

1. Combat Balance Was Off

The shapeshifter was too powerful initially. Solution: Adjusted HP on the fly, added environmental advantages for players.

2. Name Consistency Issues

Called an NPC two different names. Solution: Started writing EVERY name on paper immediately.

3. Lore Contradiction

AI suggested something that contradicted established lore. Solution: Quick prompt: "Revise this to fit a world where magic is illegal in churches."

4. The Loading Time Problem

Waiting for AI responses created dead air. Solution:

• "Let me think about that..." (roll dice for sound effect)

• Ask players what their characters are thinking

• Describe environment while generating

The Exact Prompts That Saved Me

Here are the emergency prompts I used repeatedly:

The Universal Problem Solver:

My D&D players just did 
. 
Give me three interesting consequences:
1. Immediate consequence
2. Session-level consequence
3. Campaign-level consequence

The Description Generator:

Describe [location/person/object] in two sentences.
Include: one unique visual detail, one other sensory detail, 
and one thing that suggests a story.

The motivation Revealer:

NPC [name] must [action] but the players are [interfering].
What's their real motivation that makes this more complex 
than good vs evil? How do they justify their actions?

The Tension Builder:

The scene is getting boring. Add a complication that:
- Relates to established story
- Forces a decision
- Can't be solved with violence alone

Your Zero-Prep Checklist

If you want to try this:

Before Session (2 minutes):

• Review where you left off

• Have ChatGPT open

• Blank paper for names/initiative

• Know your players' goals

• Core Prompts to Save:

• Session starter

• NPC generator

• Location description

• Combat encounter

• Plot twist generator

• Cliffhanger creator

Backup Plans:

Name generator ready

Combat encounter formula

Three random tables

Session end trigger

The Player Verdict

Post-session feedback:

• - "That was incredibly dynamic"

• - "The shapeshifter reveal was perfect"

• - "Jasper Three-Coins is my new favorite NPC"

• - "Can we play again tomorrow?"

They had no idea it was zero prep until I told them a week later.

Paladin player: "Wait, NOTHING was prepared? But everything connected!"

That's the power of AI-assisted DMing.

The Truth About Zero-Prep DMing

When Zero-Prep Works:

You know your campaign well

Your players drive the story

You're comfortable improvising

You have good prompts ready

When It Doesn't:

Complex dungeon crawls

Intricate mysteries

Major campaign climaxes

Players who need structure

The Hybrid Approach (What I Do Now)

After this experiment, I've adopted a hybrid model:

• 5 minutes pre-session: Review and basic structure

• AI during session: NPCs, descriptions, complications

• Post-session: Save what worked to campaign notes

T

his gives me the best of both worlds: preparation's structure with AI's infinite creativity.

Your Zero-Prep Challenge

I challenge you: Run ONE scene with zero prep this week.

2. Pick a low-stakes scene (tavern, travel, shopping)

3. Use the prompts from this article

4. Trust the process

5. Note what works

6. Share your experience

Tag #ZeroPrepDM and let's learn together.

Free Resources: The Zero-Prep Toolkit

Download everything you need:

• 50 Emergency Prompts - Every situation covered

• Session Structure Template - Never lose pacing

• NPC Name Bank - 200 names ready to go

• Complication Tables - When AI is loading

• Post-Session Worksheet - Track what worked

The Future of DMing

This session proved something important: AI doesn't replace DM creativity—it amplifies it.

When you're not worried about remembering NPC names or

generating room descriptions, you can focus on what matters:

• - Responding to player choices

• - Building emotional moments

• - Creating memorable experiences

Zero prep isn't about being lazy. It's about being present.

Your players don't care how much you prepared.

They care about the story you create together.

And with AI as your co-DM, that story can be infinite.