AI Co-GM: How to Use Artificial Intelligence, Obsidian, and Claude to Help You Run Your Games

By Archivist

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Here is the dirty secret nobody talks about at the gaming table.

Running a great campaign is a second job. You write the plot. You build the NPCs. You track every dangling thread the players created three sessions ago when they made a deal with that suspicious fence and then forgot about him. You prep handouts, draw maps, design encounters, and somewhere in there you are supposed to actually sleep.

Most GMs burn out not because they ran out of ideas but because they ran out of hours.

AI will not fix that problem completely. But if you use it right, it will cut the administrative load in half and free you up to do the only part of GMing that actually requires a human brain: being creative, being present, and reacting to the chaos your players generate in real time.

This is the guide to building that system. We are talking Obsidian notes, knowledge graphs, local AI, Claude, session recordings, custom tools, and a workflow that keeps your entire campaign alive and organized without requiring you to remember everything yourself.

Let’s build your AI co-GM.

The Most Important Thing to Understand First

AI is not creative. Read that again.

AI does not have ideas. It does not feel the tension when your players are one bad roll away from losing everything. It does not know that your player has been waiting three months to get revenge on the villain who burned down his character’s village. It cannot smell opportunity the way a good GM can.

What AI is genuinely excellent at is structure, pattern recognition, synthesis, and production. It can take a pile of messy notes and turn them into a clean document. It can take a concept you give it and build out twenty variations in two minutes. It can hold an enormous amount of information and retrieve exactly the piece you need when you ask.

You bring the vision. AI carries the bags.

That is the whole mindset. Never hand the creative steering wheel to the AI. Sit in the driver’s seat, tell it where you are going, and let it handle everything that would otherwise slow you down.

Part 1: Setting Up Your Base of Operations in Obsidian

Obsidian is a free note-taking application that stores everything as plain text Markdown files on your own computer. No subscriptions, no cloud lock-in, no company reading your villain’s backstory. It is the perfect home base for a GM.

Installing Obsidian and the Plugins You Need

Download Obsidian free at obsidian.md. Install it. Create a new vault and call it something like “Campaign Vault” or your campaign name.

Then install these community plugins (Settings > Community plugins > Browse):

Dataview — Lets you query your notes like a database. Want a list of every NPC in a specific city? Done. Every unresolved plot thread tagged as “dangling”? One query.

Graph View — This one is built in, no plugin needed. Press Ctrl+G. You will see a visual map of every note in your vault and every link between them. Your campaign world as a knowledge graph, right in front of you.

Canvas — Also built in. A free-form visual board where you can drag notes, images, and text cards around. Excellent for plotting out story structure, mapping faction relationships, or visualizing a mystery before your players touch it.

Templater — Lets you create reusable templates. One template for NPCs. One for sessions. One for locations. Hit a hotkey and a fresh blank form fills in automatically.

Your Recommended Folder Structure

Here is a folder layout that works well for most campaigns. This is a starting point, not a law. Adjust it to fit how your brain works.

Campaign Vault/
  00 - Dashboard/
    Campaign Dashboard.md
    Master NPC List.md
    Dangling Threads.md
    Timeline.md
  01 - Sessions/
    Session-01.md
    Session-02.md
    ...
  02 - NPCs/
    Major NPCs/
    Minor NPCs/
    Dead or Gone/
  03 - Locations/
    Cities/
    Dungeons/
    Wilderness/
  04 - Factions/
  05 - Plot Threads/
    Active/
    Resolved/
  06 - Player Characters/
  07 - Handouts/
    Delivered/
    In Prep/
  08 - Lore and World/
  09 - Templates/
    NPC-Template.md
    Session-Template.md
    Location-Template.md
  10 - AI Prompts/

The numbered prefixes keep the folders in order in the sidebar instead of sorting alphabetically. The 00 - Dashboard folder sits at the top and becomes your mission control before every session. 10 - AI Prompts is where you save prompts that worked well so you can reuse them.

The Dead or Gone subfolder in NPCs deserves a special mention. Do not delete NPC notes when a character dies or leaves the story. Move them there. Players love bringing dead NPCs back up, and having the full note preserved means you are never caught flat-footed.

The NPC Template (This One Is Critical)

Create a file called NPC-Template.md in your Templates folder. Here is a solid starting structure:

Name:
Role:
Location:
Faction:
Motivation:
Secret:
How Players Know Them:
Current Status:
Dangling Threads:
Session First Appeared:
Last Seen:
Notes:

Every NPC gets this form filled out. When you link an NPC note to a location note, the graph view shows you those connections automatically. You will never again forget that the blacksmith in Thornfield is secretly working for the Duke’s spymaster.

Connecting Claude Directly to Your Vault

This is where things get genuinely powerful, and I want to be upfront: I am recommending Claude here specifically because it handles this workflow better than most other options I have tried. There are other AI tools and local models you can use, and they will work too. But Claude has a large context window and handles long documents and messy notes cleanly, which matters a lot when you are feeding it a full campaign’s worth of material.

Claude Code is a desktop application that runs from your terminal and can read files directly from your computer. Once it is open, you can point it at your Obsidian vault folder and ask it to work with your actual campaign files rather than copying and pasting text back and forth.

Here is how to set that up:

1. Install Claude Code. It is a command-line tool, but you do not need to know how to code to use it for this. There is a graphical interface once it is running.
2. Open Claude Code in your terminal and navigate to your vault folder. On Windows, that looks something like: cd "C:\Users\YourName\Documents\Campaign Vault"
3. From that point, Claude can read your notes directly. You can say things like: “Read all the files in my NPCs folder and give me a list of every NPC whose Current Status is unknown” or “Read my last three session files and tell me what plot threads came up but were not resolved.”

No more copying and pasting walls of text. Claude reads the files, you ask questions, it gives you answers based on your actual campaign.

You can also tell Claude to write new notes directly to the vault. After a session debrief, you can say: “Based on everything we just discussed, write a session summary file in my Sessions folder in the same format as my other session files.” It creates the file. You open it in Obsidian, tweak anything that needs tweaking, and you are done.

The combination of Obsidian’s linking and graph view plus Claude reading your actual files is the closest thing to having a second brain that actually knows your campaign inside and out.

Part 2: Brainstorming and Plot Planning With AI

This is where the collaboration gets genuinely fun.

You have an idea. It is half-formed. You know the broad strokes: the players are going to discover a secret cult has been operating inside the city watch, and someone they trust is involved.

That is a premise. What you need is a plot.

Open Claude (or your local AI of choice) and start talking to it like a collaborator.

Example prompt:

“I’m running a TTRPG campaign set in a grimy city-state fantasy world. My players are about to discover a secret cult has infiltrated the city watch. I want the investigation to take 3–4 sessions. Give me the key beats of the plot, three suspects with different levels of guilt, two red herrings, and a twist reveal for the finale. The tone is dark but not hopeless.”

You will get back a solid structural scaffold in under a minute. It will not be perfect. Parts of it will be generic. But it gives you something to react to, and reacting is much faster than generating from scratch.

Take what works. Throw out what does not. Ask follow-up questions: “Make the second suspect more sympathetic,” or “The twist feels predictable, give me three alternatives.”

This back-and-forth is where the real value is. You are not accepting AI output. You are using AI output as a sounding board for your own instincts.

The Red Herring Problem (AI Is Surprisingly Good at This)

Red herrings are hard to design because you know the truth. Every time you look at your red herring, you see through it because you built it.

AI does not know the truth unless you tell it. So you can describe your mystery to it without revealing the solution and ask: “What details would make a clever player suspect the wrong person? What evidence could legitimately point somewhere innocent?”

The AI will tell you what your mystery looks like from the outside. That is exactly what you need.

Part 3: Building NPCs, Mysteries, and Entire Plot Arcs

Once you have a structure, AI becomes your fast-draft machine.

For NPCs:

“Give me a full NPC for a corrupt city watch captain. He genuinely believes he is protecting the city but has compromised himself step by step over ten years. Give him a name, a physical description, a verbal tic, a motivation, a secret, and one detail that makes him sympathetic even when the players learn what he has done.”

Paste the output into your Obsidian NPC template. Edit it until it feels right. Now you have a complete character in five minutes instead of thirty.

For mysteries:

AI is excellent at the logic layer of mysteries. Give it your clues and ask it to tell you: do these clues actually point to the answer, or does a player who finds all three still have no idea who did it? It will find the gaps in your mystery’s logic before your players do.

For complete plot arcs:

You can hand AI a three-sentence premise and ask it to give you a full three-act structure: the inciting incident, the complications that raise the stakes, the point of no return, and the finale. Use it as a first draft. Tear it apart. Keep the bones and replace the flesh.

The Whole Plot on Paper

One technique that works extremely well is writing out your entire campaign plan in a single long document and giving it to your AI session by session as context. Tell it: “Here is my campaign document. We are in session 12. The players just did X. What threads from earlier should I be pulling forward? What have they forgotten that I should remind them about?”

The AI becomes your campaign continuity advisor.

Part 4: Recording Sessions and Turning Audio Into Gold

This might be the single most powerful thing in this entire article.

Record your sessions. All of them. You do not need professional equipment.

If you are playing in person, set your phone in the middle of the table and hit record. Any voice memo app works. If you are running your game on Discord, there are bots that will record the whole session for you. Craig is the most popular one — it captures each player on a separate audio track, which makes the transcript cleaner. Either way, you are getting the session on record without any effort during the game itself.

After the session, drop the audio into whichever AI transcription tool you prefer. Most of the major AI platforms can transcribe audio directly now. The transcript will not be perfect but it does not need to be. You are not publishing it. You are feeding it to another AI to extract the useful parts.

Step 1 — Get the transcript. Use whatever tool you have available to turn your recording into text. It does not have to be pretty.

Step 2 — Feed the transcript to your AI. Use this prompt framework:

“Here is a transcript from session [number] of my TTRPG campaign. Please do the following: 1. Write a clean session summary in 3–4 paragraphs. 2. List every NPC who was mentioned or appeared. 3. List every plot thread that was introduced, advanced, or left unresolved. 4. List any promises the GM made to players (lore reveals, future events, etc.) that have not happened yet. 5. Flag anything that contradicts established facts from earlier sessions if I provide them.”

What comes back is your complete session notes, written for you, in five minutes.

Step 3 — Drop it into Obsidian. Paste the AI-generated notes into a new session file. Link every NPC mentioned to their NPC note. Tag every unresolved thread as “dangling.” Your knowledge graph updates automatically.

Now press Ctrl+G and look at your graph. You can see which NPCs keep showing up, which locations are central to your story, and which plot threads have been sitting untouched for four sessions.

Part 5: Never Lose a Plot Thread Again

Dangling plot threads are the silent killer of long campaigns. Players care about things you think they forgot. They will bring up that throwaway NPC from session two at the worst possible moment.

Here is the system.

Every session note gets a section called “Open Threads.” Every thread gets a status tag: #dangling, #active, or #resolved. In Obsidian Dataview, create a query in a master file called Campaign Dashboard.md:

LIST
FROM #dangling
SORT file.mtime DESC

This gives you a live list of every unresolved thread in your entire campaign, updated automatically every time you add a new note. Before each session, open that list and pick two or three threads to weave in. Your players will think you have been planning this for months.

You were. You just had a system keeping track.

NPC Continuity

Same principle applies to NPCs. Any NPC the players have interacted with gets a “Current Status” line in their note. After each session, update it. If Mirela the fence has not appeared in six sessions but is still an open thread, your dashboard will show you that.

Give the AI your NPC file and ask: “The players are heading back to Thornfield. Which NPCs should realistically be in different situations now given what has happened? What might have changed for each of them in the two in-game months since the players left?”

The AI will generate logical continuity for you. Your world feels alive. It is alive, and AI is maintaining the simulation while you focus on the table.

Part 6: Creating Player Handouts With AI

Handouts are one of the best tools a GM has. A physical or digital prop that the players can actually hold and examine creates immersion that a hundred words of description cannot match.

Here is where the real power of the GM-plus-AI workflow shows up. You are the creative one. You write the content. AI executes the presentation.

Think about how that changes things. You know what the villain’s letter says. You know the tone, the threat, the exact wording that fits your campaign. You write it. Then you tell the AI: “Take this letter and build me an HTML5 document that displays it as aged parchment with a wax seal graphic, period-appropriate fonts, and a yellowed paper texture. Make it something I can open in a browser and screenshot to send to my players.”

You wrote the letter. AI built the prop. The players get something that looks like it came out of a professional game module. You spent fifteen minutes total.

That is the pattern. You direct. AI executes. Every time.

More examples of that workflow in action:

You write a coded cipher the villain’s agents are passing around. You tell AI: “Take this message and build an HTML document that shows it as a torn note with faded ink, and add a separate panel below that shows the decoded version revealed by a button click.”

You draft a broadsheet newspaper with three story items you already have in mind. You tell AI: “Format this as a fantasy city newspaper with a masthead, columns, and a decorative border. Make it printable.”

You create a treasure map with clues pointing to a location in your world. You tell AI: “Turn these directions into an HTML5 interactive document styled like a water-damaged nautical chart.”

The AI is not inventing your handouts. You are. The AI is doing the graphic design and production work so you do not have to spend three hours in a word processor getting the fonts right.

When you want AI to write the draft too:

Sometimes you just need a starting point. That works too.

“Write a threatening letter from a medieval crime lord to a merchant who owes him money. The crime lord is educated, cultured, and extremely dangerous. The letter should be polite on the surface and terrifying underneath. About 150 words.”

Read it. Rewrite the parts that do not sound like your villain. Keep what works. Then hand it back to AI for the production step.

“Now take this letter and build me an HTML5 document styled as aged parchment with period fonts. I want to screenshot it and send it to my players.”

Done. Two prompts. One prop your players will remember.

Part 7: Using Claude Code to Build Custom GM Tools

This is the part that sounds technical but is easier than you think.

You do not need to know how to code. You just need to know what you want.

Claude Code is a version of Claude that can write and run actual code. You do not need programming experience to use it. You describe what you want, and it builds it.

Here are real examples of tools you can have built in an afternoon.

HTML5 Character Creation Walkthroughs

If you have new players who are struggling with character creation, have Claude Code build them a guided HTML5 document. Tell it something like:

“Build me a single HTML file that walks a new player through creating a D&D 5e character step by step. Include a step for choosing a race, class, and background. For each choice, show a brief plain-language description of the option. At the end, generate a formatted character summary they can print or screenshot. Make it mobile-friendly.”

Claude Code will write the entire HTML, CSS, and JavaScript. One file. No installation. Your players open it in any browser and it walks them through the whole process. You hand it to your new players and never have to explain character creation one more time.

Completed NPC Generators

“Build me an HTML tool that generates a random NPC with a name, a one-line physical description, a motivation, a secret, and a quirk. Add a button that generates a new one. Add a button that lets me save the NPC to a text file.”

Done. You have a custom NPC generator tuned to your preferences, runnable in any browser, built in twenty minutes of conversation.

Random Tables and Tools

Any random table you use at the table can become an interactive tool. Weather generators, encounter tables, treasure generators, name lists by region — all of it. Describe what you want, let Claude Code build it, and keep a folder of your custom GM tools.

Session Timer and Tracker

“Build me an HTML session tracker. It should show a countdown timer from 3 hours. It should let me add initiative entries during combat. It should have a notes section where I can type reminders mid-session. Make it look dark and atmospheric, like a game master’s screen.”

You now have a browser-based GM companion that sits open on a second monitor during your sessions.

Part 8: The Full Workflow in Practice

Let’s put it all together so you can see what a real pre-session and post-session workflow looks like.

Before the Session (30 Minutes)

1. Open your Obsidian Campaign Dashboard. Check the dangling threads list. Pick two or three to weave in this session.
2. Open your AI and say: “Here is my session plan for tonight. [Paste plan.] What complications could arise if the players go somewhere unexpected? What are three things that could go wrong that I should be prepared for?”
3. Use the AI to draft any handouts you need for this session.
4. Review your active NPC notes. Update any “Current Status” fields that have changed since last session.

During the Session

Run your game. Be present. React to your players. The prep is done. Trust it.

If something unexpected happens, you can have Claude open on a second device in the background. Type: “My players just decided to [X] instead of [Y]. What are two quick ways I can adapt my prepared plot to accommodate this?” You will have options in thirty seconds.

After the Session (20 Minutes)

1. Start the transcription service on your recording.
2. While you wait, do a quick brain-dump in Obsidian: anything memorable, any promises you made, any NPC moments that felt significant.
3. When the transcript is ready, feed it to your AI with the prompt from Part 4.
4. Paste the AI-generated notes into your session file.
5. Update NPC statuses and link any new threads. Tag unresolved ones as #dangling.

Next session, your dashboard is already updated and ready.

The Right Way to Think About All of This

Here is the line you need to hold onto.

You are the creative director. AI is your production team.

The creative decisions are yours. The villain’s real motivation. The moment you decide to flip the script and make the patron the enemy. The choice to let a player’s character die because that is the story it was always building toward. The instinct that this session needs to slow down and breathe instead of sprint. Those calls require knowing your players, caring about your table, and understanding the specific story you are all telling together. AI cannot do that. It never will.

What AI can do is handle the mental labor that drains you before you ever sit down to play.

It keeps track of the NPC cast so you do not have to hold forty names and secrets in your head. It maintains the list of dangling plot threads so nothing falls through the cracks. It produces the first draft of the document so you can focus on shaping it instead of staring at a blank page. It formats the prop so it looks like a real artifact instead of a Word document in Times New Roman.

You bring the vision. AI executes it the way you want it presented. You stay creative, stay present, and stay in command of your own story.

That is the whole deal. Use it for that. And run the campaign you always wanted to run but never had the hours to pull off.

If this guide helped you get more time at the table and less time at your desk, share it with your GM. Or your player who has been secretly thinking about running their first game. And if you pick up any tools through the links above, thank you — it supports more content like this.