[Guide] : How AI Can Enhance and Support a Play-by-Post RPG as the Game Master or Supporting Tool

Introduction

In a play-by-post (PbP) RPG, players and the Game Master (GM) communicate and play the game through written messages, typically on a forum or messaging platform. The GM has to manage a wide range of tasks—describing settings, handling NPCs, interpreting rules, and tracking story progression—all while ensuring that each player’s actions and decisions impact the evolving story. With AI tools, GMs can streamline many of these tasks, allowing for quicker, more consistent responses and a deeper, more immersive experience for everyone involved.

This guide explores how AI can assist GMs in running a PbP RPG, from automating NPC dialogue and encounters to tracking character progress and resolving complex rules. With AI support, the GM can focus on what matters most—creating an engaging and dynamic story.

1. Generating NPCs and Dialogue in a PbP RPG

NPCs are essential to any RPG, especially in PbP games, where their responses and motivations drive much of the interaction. AI can quickly generate detailed NPCs, complete with backgrounds, motivations, and dialogue styles, which can save the GM time while still delivering rich character experiences.

Example AI Prompt for NPC Creation:

“Generate an NPC, an elderly hermit who lives in a secluded cave near the village of Greyhaven. The hermit has knowledge of a hidden treasure buried deep in the mountain but refuses to share this information unless the players can prove themselves worthy. Include their personality, appearance, and dialogue style.”

Example Result:

Name: Eryndor the Wise

Appearance: Eryndor is a bent figure with a long, silver beard almost reaching the floor. His weathered robes are patched with various colours and patterns, and his eyes gleam with a mischievous glint.

Despite his frail body, his voice is surprisingly strong and confident.

Personality: Eryndor is eccentric, with a sense of humour that often borders on the absurd. He’s a collector of oddities and riddles, and while he’s helpful, he enjoys testing those who seek his knowledge.

Dialogue Style: ‘Ah, you seek what is hidden, do you? Many have come before you, eager for riches, but few have been worthy. Tell me, what is the true cost of wisdom? Or perhaps you are ready to prove your worth? Only time will tell.'”

This AI-generated NPC gives the GM a rich character to roleplay, freeing them from needing to spend hours crafting backstories and dialogue for each new character the players encounter.

2. Creating Encounters and Challenges with AI

PbP RPGs may not have the same real-time combat as tabletop RPGs, but that doesn’t mean encounters aren’t still an essential part of the game. AI can help generate combat or environmental encounters, puzzling scenarios, and character challenges based on the players’ decisions and locations in the story.

Example AI Prompt for Encounter Creation:

“Create a tense, environmental encounter for a group of adventurers exploring the abandoned ruins of an old temple. They must navigate through traps, shifting platforms, and strange magical barriers. Include potential hazards and a final obstacle before they can access the hidden treasure room.”

Example Result:

“As the adventurers step deeper into the temple, the air grows thick with dust and the scent of decay. The floor creaks underfoot, and a strange glow emanates from the walls, illuminating the darkened corridors. Suddenly, a loud click echoes through the room, and the floor beneath them begins to shift.

They must navigate a series of crumbling stone platforms that rise and fall erratically. The magic that once held these platforms in place is unstable, and any misstep could send them plummeting into a pit of jagged rocks below. Further ahead, a mystical barrier blocks the path, shimmering with arcane symbols. The players will need to solve an ancient riddle or activate a hidden mechanism to deactivate the barrier and access the treasure room.”

AI-generated encounters like this allow GMs to create complex scenarios in a short amount of time, keeping the PbP RPG engaging without bogging down the pacing.

3. Automating Dice Rolls and Action Resolution

Managing dice rolls and resolving actions in PbP RPGs can be tricky since all actions are communicated in writing. AI tools can automate dice rolls and action resolutions, ensuring consistency and speeding up game progression.

Example AI Prompt for Action Resolution:

“Resolve a Strength check for the character Zane, who is trying to lift a large stone blocking the path. He has a Strength modifier of +2. Roll a d20 and provide the result.”

Example Result:

“Zane rolls a 14 on his d20, with a +2 modifier. The total result is 16. Zane grits his teeth and pushes with all his might. The stone shifts slightly but is still too heavy to fully move. He will need assistance or a stronger effort to clear the path.”

By automating these aspects, the GM can focus more on the narrative while letting the AI handle rule enforcement.

4. AI as a Responsive Narrator and Storyteller

In PbP RPGs, the GM’s narrative is key to immersing players in the world. AI can act as a responsive storyteller, adapting to players’ actions in real time and adjusting the storyline accordingly. The AI can generate detailed descriptions of environments, character interactions, and ongoing events.

Example AI Prompt for Narrative Development:

“The players enter the ancient library beneath the city, where dusty tomes line shelves that stretch high into the air. The air is thick with magic. What does the room feel like? What do they discover upon entering?”

Example Result:

“As the players step into the library, the temperature drops, and the faint smell of old parchment fills the air. The shelves seem endless, stretching into darkness. In the center of the room, a large, ornate desk stands, covered with scattered papers and open books. A soft glow emanates from a tome resting upon the desk, its pages flipping by themselves. The room is silent, save for the rustle of turning pages and the occasional thud of a falling book. Something ancient stirs here, as though the library itself is alive.”

With this AI-generated response, the GM can immerse players in the setting without having to manually describe every element.

5. Tracking Player Progress and Character Development

PbP RPGs often involve long-term character progression.

With AI, GMs can track character stats, achievements, and important story events automatically, reducing the need for players to update their character sheets manually and keeping everything in one place.

Example AI Prompt for Tracking Progress:

“Track the character Aria’s journey. She has completed the quest to defeat the Shadow Lord and gained 500 XP. She has now reached Level 3. What does this mean for her abilities and equipment?”

Example Result:

“Aria’s victory over the Shadow Lord has earned her 500 XP, bringing her total to 1,500 XP. She has now reached Level 3 and gained the following upgrades:

• New Ability: Divine Smite – Once per day, Aria can channel divine energy into her weapon, dealing an additional 2d6 radiant damage.
• New Equipment: Cloak of Shadows – This enchanted cloak grants an advantage on Stealth checks in dim light or darkness.
• Health increase: Aria’s maximum hit points increase by 6, based on her Constitution modifier.”

The AI helps the GM quickly calculate and track character development changes, ensuring that the story remains consistent.

6. Using AI for Rules Interpretation and Resolution

In PbP games, there’s often no immediate way to resolve complex rules questions. AI can interpret rules in real-time, ensuring that the game runs smoothly and that everyone adheres to the mechanics.

Example AI Prompt for Rules Interpretation:

“Interpret the rules for casting a spell with a concentration requirement while the player is in combat. What happens if the player is damaged during the spell?”

Example Result:

“When a player is concentrating on a spell and takes damage, they must make a concentration saving throw. The DC for the saving throw is either 10 or half the damage taken (whichever is higher). If the player fails the saving throw, they lose concentration, and the spell ends. If the player succeeds, the spell continues as normal.”

By providing instant rules interpretations, AI can help reduce the workload of the GM, ensuring that the game runs smoothly even in more complicated scenarios.

Conclusion

In play-by-post RPGs, where every action and conversation is tracked through writing, AI can be a valuable tool in supporting GMs and enhancing the experience for all players. By automating NPC creation, encounters, dice rolls, and story progression, AI allows the GM to focus on the heart of the game—the narrative and player interaction. Furthermore, by streamlining character tracking and rules interpretation, AI ensures that gameplay remains consistent and enjoyable, even in long-running campaigns.

With AI as a supporting tool, PbP RPGs can be more immersive, flexible, and fun for everyone involved, allowing GMs and players alike to explore new stories with fewer barriers.