Designing a Dungeon: Part 7—GM Text

In the seventh installment of our series on designing a new dungeon crawl adventure for the patrons of the World of Aetaltis Patreon, we talk about writing fantastic GM text.


Step 1: We talked about choosing a map. Maps are really fun to draw, but there are times when you want something that's ready to go. In this case, I picked a cool map from Dyson Logos available in in his map pack on DriveThruRPG.

Step 2: We came up with the original purpose of the adventure site. After a bit of back and forth I settled on a dwarven Diplomatic Entrance to a Deepland Hall. After that I came up with a rough idea of what all those rooms were used for when first built.

Step 3: We picked out the major threats our players will face, settling on some kobolds, a party of filthy bandits, and a big nasty troll.

Step 4: In 'How It Came to Be' we put together a history for our ruin that we can use to guide us as we start fleshing out the rooms.

Step 5: We looked at how to outline the room and talked about the importance of identifying a a purpose in the adventure for each room.

Step 6: In this post, we looked at writing the boxed text that the GM reads aloud to the players when they first discover a room.

Step 7: Writing the GM Text

As you may remember, the GM text is information that may or may not get shared with the players. This could be additional color text, like this history of the room, but it also includes rules, monster stats, and other crunch needed to run the game. Today I'll share some tips and tricks that will help you to write forking amazing GM text.

GM Text is a Tool

This is the single most important thing I'll tell you in this article! You're not writing prose fiction (even if there is some prose fiction in the GM text). You are creating a tool. It must serve the purpose for which it is made and do so in the most efficient way possible. In this case, the purpose is to help the GM run an amazing game for the players. This idea of GM text being a tool is going to be the theme throughout the rest of this article and should always be foremost in your mind. 

The Template

I recommend that you create a template for your GM Text and stick to it. Specifically, arrange the content in the same way for every GM text section. By using a template the GM learns where to look for important information.

You can use any template you like, but here's the one I like to use:

  1. Room Number and Name
  2. One Line Room Summary
  3. <Boxed Text>
  4. Labeled Details
  5. Monster Stats
  6. Treasure List

By sticking to a consistent format for the GM text, you make it easy for the GM to quickly find the information they need.

A quick aside: remember that we're talking Dungeon Design here. This approach works great for 40 room descriptions in a row, but its not necessarily the perfect approach for other types of adventure encounters—but that's a topic for another day.

Room Names

Please give your rooms names. If the GM is flipping through the book looking for a room, a name like "13. The Temple" is going to be a lot more useful to the GM than just "Room 13".

Also, when you give the room a name, pick something descriptive. No need to get cute. Again, this is a tool, and a clever room name like "12. A Dark Destiny" isn't going to help the GM at all. Choose names like "King's Ruined Bedchamber," "Filthy Kitchen," or "Troll Cave," that let the GM immediately identify what the room is.

One Line Room Summary

Before the boxed text and after the room name, include a one line summary of the room. This should inform the GM about what the room is, the room's purpose, and what the players will find there (especially foes). As an example, let's go back in time to when we talked about the Bandit's Common Room in Part 5 of this series. A one liner for that room might read like this:

The characters have their first encounter with the bandits, quickly learn what they are up against, and are forced to choose between violence or negotiation.

For a GM scanning the adventure, a line like this makes it easy to get the basic idea of what each room is about. If they're in the middle of running the game, the line will quickly refresh their memory when the players reach the room. And notice that I don't need to describe the room in my summary, because I already covered that by choosing a clear, descriptive name for the room.

Labeled Details

After the boxed text come labeled details. Please note that the "labeled" part is important. If you follow your boxed text with a bunch more text that isn't boxed, that isn't a useful tool. If the GM has to dig through a wall of text to find the one detail they want, it slows the game down and can lead to mistakes and omissions. The labels are important!

So let's say you want to share some history that will help the GM tell the story. In that case, just add the label "History" before you tell the tale. Or if you want to give information about a trap in the room, use the label "Pit Trap" before you tell the GM about it.

You should also include some additional information about the room's primary features. A primary feature is anything that a player is likely to ask about after they hear the boxed text. For instance, if you describe "intricately carved pillars" in your boxed text, you owe the GM a detail labeled "Pillars" that includes information about those carvings. As we've said before, a GM can ignore something they don't like, but don't make them write the adventure themselves. Give them what they need to run a great game.

Include the Rules

Include any rules, DCs, or other crunch content the GM might need. If the GM or players have to go back to the rulebook mid-game, it's going to bring the story to a screeching halt.

For instance, if the floor of the room is littered with broken stone, don't just tell the GM that it's Difficult Terrain. Tell them it's "Difficult Terrain which reduces movement speed by half." Just a few extra words can mean the difference between an awesome story that keeps flowing and a game session the grinds to a halt with a conversation like this: "What is difficult terrain again? Half movement? Can you look that up?"

The same is true for DCs. If there is a wall that the characters might try to climb, list the DC to climb it. If there is a door that is swollen shut, list the DC to break it open. The game will be more fun (and thus people will like your adventure more) if you help the GM to keep things moving and avoid unnecessary trips to the rulebooks.

Finally, give the GM the tools to deal with the most likely questions a player is going to ask. For example, if you describe "fabulously rare pink marble flooring," maybe you want to take a couple sentences to describe the DC to remove the floor panels, their weight, and their value. After all, give a description like that and most of the players I know are going to see GP.

Monster Stats

The next section I include are the stat blocks for monsters. Even if the players are going to encounter the monsters before they get a chance to examine the room, I prefer to include the monster stat blocks after the labeled details. This keeps the labeled details closely associated with the room name and boxed text. If you put the stat blocks before the labeled details you risk making it difficult to tell, at a glance, which room a labeled detail goes to. What is more, if your adventure ever goes to print, putting stat blocks first can even bump some of the labeled details to the next page. When this happens, you risk the GM not even seeing an important detail until its too late. "Oh, sorry guys, I forgot that there the desk was covered with papers. The description was on the next page."

Treasure List

At the end of the GM text I list everything in the room that a player might want her character to take and its value. Even if you've described the item earlier in the GM text, list it here. Including this list at the end helps with all sorts of things, including answering questions like "Do we find anything else in the room?" and "Which room did we find that necklace in?"

I also like to group items by where they are located. This makes it easier to visualize (and remember) where items are in the room. 


There are a few useful items lying around the fire, including:

  • Rope: 50’ hempen, 1 gp, 10 lb
  • 5 small leather bags: 1d6 bird feet per bag.
  • Tattered canvas bag: 1 lb. of perfectly round red glass beads, the wriggling body of a half-dead squirrel, and 5 days of blood-soaked rations (2 lbs), no value
  • 108 gp.

The goblin shaman has a number of valuable items in a sack behind the pillar:

  • Five pieces of ancient dwarven silverware: 10 gp, 2 lbs
  • 20 gp, 12 sp, 32 cp

    Include the Rules

    Yep. I'm saying it again! Include the rules for the treasure. If there is a weapon in the room, just include the stats for it. Don't make someone break away from the game to look up the rulebook. If there is a potion, include the rules for its effect, even if you just give a quick summary.

    Throw in A Little Description

    While you're at it, you can make your treasure more interesting by including a bit of description in this section. So instead of listing:

    • A crudely carved 8” obsidian statue

    Try describing:

    • A crudely carved 8” obsidian statue of a faceless man: A DC 15 Knowledge (religion) skill check identifies the statue as a representation of Endroren. The statue has no value.


    So there you go! That's my advice for writing great, useful GM text for your adventure!

    If you want more examples, you can wait to see how I handle the GM text for the dungeon we're designing here, but if you'd like to see some of these techniques in action right now, check out the Temple of Modren. It's an adventure in our first Aetaltis book, the Heroes of Thornwall. The PDF is free, and although the rules are for Pathfinder (we're working on a 5E conversion!), you can see the tricks and tips described here used in a finished adventure.

    And now I'm off to finish off this adventure so we can get to playtesting! Talk to you soon!

    Marc Tassin is the creator of the World of Aetaltis and the founder of Mechanical Muse. He's been gaming since 1985, and he's also a published author and game designer. He's had the opportunity to write for some of his favorite RPG products over the years, including Shadowrun and Dragon Magazine. You can find him at Gen Con every year, usually lurking about near the Exhibit Hall or the Writer's Symposium rooms! To support his Aetaltis patreon, just click here!

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