Building a TRPG

How it works in five minutes

Chapters and phases

A chapter is one session. Put one expedition or one day of events in a chapter. A phase is a scene (a beat) within the chapter. Split wherever the goal changes, such as “Regroup”, “Crossing the corridor” and “Ambush”.

What the narrator does and what the server does

The narrator (the AI) writes the description of the scene and the cast’s lines. The server decides the roll, the result, values such as stamina, the clocks and the move to the next scene, and hands them to the narrator.

Thanks to this split, the stamina figure and the remaining actions never drift mid-conversation. Results are written as the dice decided, not as the narrator felt. As the author, you only write “what happens leads where” in the settings, and the story moves reliably.

What happens behind one player action

When the player sends one action, the server works in this order.

1. Remaining actions drop by 1: only in chapters with an action limit.
2. Clocks tick: clocks with an “Every action” rule advance.
3. The referee decides the check: with the “TRPG (referee)” play style, it decides whether a check is needed, which skill and how hard, and rolls first when one is needed. A success opens clues and advances clocks tied to checks.
4. Encounter tables are drawn: on turns without a check, an encounter table is drawn when its timing comes up.
5. Transitions are checked: if a check result or a full clock satisfies a transition, play moves to the next phase. The new phase’s entry instruction, state override and place take effect here.
6. The narrator writes: it receives everything settled so far and writes the scene.
7. State is updated: the server picks changes such as “lost 5 stamina” or “picked up a leather pouch” from the narrator’s text, checks the ranges and applies them. Threshold notes, “When the state reaches this” transitions and AI-judged transitions are checked here too.

Play styles

Pick one of three in “Gameplay > Rules & checks > Play style”. Picking one lines up the dice settings below for that way of playing. What the player does changes with each style.

Conversation

• What the player does: just writes. There are no checks.
• Settings it fixes: dice checks are OFF.
• Suits: stories led by conversation and relationships. Status fields, phases and clocks still work in this style.

Narrator asks for checks

• What the player does: writes, then rolls with the card that appears when the narrator calls for a check. They can also roll on their own from “Use a skill”.
• Settings it fixes: dice ON, mode “With success/failure judgment”, timing “AI decides automatically (default)”.
• Suits: stories that want dice tension only at the high points.

TRPG (referee)

• What the player does: just writes. The server rolls automatically when a check is needed. Rolling on purpose with “Use a skill” offers next actions built on the result.
• Settings it fixes: dice ON, checks on, timing “Let the referee decide”, difficulty model “Three tiers with modifiers”.
• Suits: stories that want full exploration, combat and mysteries with skills, state and clocks. The rest of this page assumes this style.

Build order

Phase fields pick skills, status fields and places from lists. The editor steps follow the same order: build the groundwork in the Gameplay step, then move on to the Chapters step, and every option is ready to pick when you make phases. One line is enough for each step.

1. Play style (“Gameplay > Rules & checks > Play style”)
   Decide: whether the server handles checks or the narrator asks for them.
2. Status fields (“Gameplay > Rules & checks > Status fields”)
   Decide: the values to remember across scenes. For example stamina, inventory, mana stones.
3. Skills (“Gameplay > Rules & checks > Dice checks”)
   Decide: the actions where success or failure is interesting. For example observe, search, fight, dodge, pick locks.
4. Difficulty (the dice “Difficulty model” and “Difficulty chosen by players”)
   Decide: which situations make checks easier or harder. For example searching is one tier harder when near death.
5. Map (“Gameplay > Map”)
   Decide: where leads where. For example guild → first floor → camp.
6. Chapters (“Chapters”)
   Decide: what one session achieves, and the action limit. For example reach the iron door at the back of the first floor, 30 actions.
7. Phases (“Chapters > Advanced settings (optional, for detailed authoring) > Phases (this chapter’s progression)”)
   Decide: which phases play passes through and what moves it on. For example the corridor leads to the hall when “Exploration progress” fills.
8. Handouts and chapter directives (handouts in “Chapters > Rules for this chapter”, directives in the chapter’s advanced settings)
   Decide: the secret only the player knows, and what the narrator follows every turn.

Start from a sample

In “Gameplay > Start from a sample”, pick a TRPG sample prepared by the team to copy its gameplay settings into your story. Starting from a sample’s chapters and phases gives you a playable shape you only need to rewrite for your own story.

• Your current settings in the chosen parts are replaced by the sample. Copying chapters & phases removes your current chapters and the conversations played in them.
• Per-cast stances and the cast appearing in each chapter are not copied. Set them after deciding your story’s cast.
• Fields pointing to skills, status fields, or places stay when you copy rules & checks and the map together. Copy all three and the sample’s machinery runs as is.

Where each device shines

Every example comes from chapter 1 of “Records of the Royal Capital Ruins”. Chapter 1 runs “Regroup → Stone corridor → Ambush / Flooded hall → Sealed iron door / Retreat”.

Export / import as YAML

“Gameplay > Export / import as YAML” writes gameplay, the map, and chapters with phases to a YAML file. Keep a backup, revise everything at once in a text tool, or bring the setup into another story.

To import, paste YAML or choose a file and press “Check contents”. It shows how many chapters, phases and state fields there are, and what will be left out (stances for cast not in this story, missing images, and so on). Pick the parts to copy and press “Import”; only what passes the same checks as saving goes in. Cast and images are written by name, so in a story with cast of the same names, stances and relation modifiers reconnect as they are.

Status fields and thresholds

In “Gameplay > Rules & checks > Status fields”, decide the values the server keeps. There are five types: Number, Stage, Yes / no, Text and List. Set “Changed by” to “Narrator’s narration” to pick changes from the prose, or “Server only” so it changes only through a chapter’s or phase’s “State overrides”.

In “Description (optional)”, write what the field records. The server uses it when picking changes from the text, so a description means fewer missed updates.

A list such as an inventory can be marked “A field for the player’s own belongings”. With the mark, only what remains in the player’s hands at the end of the turn is added from the narration. A weapon a cast member is holding, or something borrowed and handed straight back, stays out, so the State tab’s belongings match the story. Number fields can also take “Max change per turn from narration”, so values like noise that should climb a step at a time move gradually instead of jumping.

Numbers can have thresholds. Crossing one passes a “Note for the narrator”, and “Effect” can be “Narration only”, “End the chapter” or “Lost (play ends)”.

Cast state and relations

Turn on “Keep per-cast state” in Status fields and the server keeps a relation value, bonds and a mood for each cast member. Each relation step can have a “Label for each step”, and the player’s “Relations” tab and the narrator receive that label.

The sample uses relations from −3 to 3, named “hostile, distrust, wary, neutral, friendly, trust, devoted”. The bond words are “comrade, doubt, debt”. Relations can also be a condition for skill modifiers, so the deeper the trust, the more easily teamwork skills succeed.

Skills

Create skills in “Gameplay > Rules & checks > Dice checks”. There are two kinds: “Check (a target number decides the outcome)” and “Lottery (an outcome table decides the result)”. You can have up to 16 skills.

A skill’s “Description” appears under the 🎲 line as “what is at stake” when the referee rolls. Writing what success earns, such as “spot traps, ambushes and monsters’ weak points”, lets the player grasp the check at a glance.

Skills named after cast members turn “who do I hand this to?” into part of the play.

Three difficulty tiers and modifiers

Set the dice “Difficulty model” to “Three tiers with modifiers” and checks use three tiers: Regular (the skill value), Hard (half) and Extreme (one fifth). The referee picks the tier to match how reckless the action is. Hard attempts such as retries become Hard.

A skill’s “State modifiers” shift the tier with the situation. The source is a “State field” or a “Cast relation”, and the total is capped at two tiers. The words in “Reason (shown in the 🎲 line)” appear on the check line as written.

There is no tier easier than Regular. An “easier” modifier works by bringing a Hard or Extreme check back one tier. Modifiers apply with “Three tiers with modifiers”.

Uses per play and recovery

A skill’s “Uses per play” is how many times it can be used in one playthrough. On a strong skill, it makes the player think about when to spend it. In the sample, Rina’s strike has 5 uses and Ayame’s iai has 3. The player’s “Use a skill” shows the remaining uses.

“Restore skill uses” in a chapter’s or phase’s “State overrides” refills uses to the limit on entry. Restoring “All skills” in a camp chapter makes a breather where trump cards come back.

Changing state by roll result

In a skill’s “Change state by result”, list which state fields move for each roll result. On every roll the server changes the state, and the 🎲 line shows “Health -1 · Noise +1”. When the player simply writes an action and the referee calls for a roll, the chosen skill’s effects apply just the same.

A critical success also gets the success effects, and a fumble also gets the failure effects. With the settings above, a fumble means Health -2 and Noise +2. How a field moves depends on its type: numbers go up or down, stages step up or down, yes/no fields take a value, and lists add or remove an item. Numbers stop at the field’s range and stages stop at either end. Put a “Lost” threshold on Health and repeated failures carry the story all the way to an ending.

A phase’s “Extra roll effects” under “Devices and cast” adds effects for that phase only. They stack on the skill’s own effects, so a failed Observe in a trapped room can cost health, or a failed Run during a chase can, giving each scene its own weight. Leave the skills empty to apply to rolls of any skill.

The narrator is told what moved and narrates to match. The step that reads state changes from the narration does not count the roll’s changes a second time.

Difficulty chosen by players

Turn on “Let players choose a difficulty” in “Gameplay > Rules & checks > Difficulty chosen by players” and the player picks a level when starting. Each level sets an “Action limit multiplier” and a “Check adjustment”.

The multiplier applies in chapters with an action limit, and the check adjustment applies when the difficulty model is “Three tiers with modifiers”.

Clocks

A clock is a gauge that fills as actions pile up. Place up to four in a phase’s “Devices and cast”. The “Kind”, progress or danger, only changes the colour; both work the same way.

“Advance rules” trigger on “Every action”, “On a successful check”, “On a failed check”, “On a critical success”, “On a fumble”, “When judged closer to the goal” or “On moving to a location”. “When judged closer to the goal” is decided by the referee looking at the action.

The most effective pattern is racing a danger clock against a progress clock. If progress fills first, play moves on; if danger fills first, the party lands in trouble. Every action carries the tension of “hurry, or play it safe?”.

What a full clock does goes in a “When a clock fills” transition. The “Note when full” is one sentence passed to the narrator the moment it fills. The sample writes “Drawn by the noise, monsters show themselves.”

A phase clock is used only inside its phase. It starts from its initial value every time the phase is entered and does not carry over to other phases. “Every N actions” also counts actions since entering that phase.

Rules that move “only while…”

“Add a condition” on an advance rule attaches state-field conditions (“anything but” works too, and several combine with “and”). The rule moves the clock only while the condition holds. It works for phase clocks and story-wide clocks alike.

Clocks that start from state, or whose pace changes with state, fit inside one phase without splitting it. A story-wide clock stays off the chapter tab and out of the narrator’s view while it sits at its initial value and none of its forward rules hold.

Variations by state

“Variations by state” under a phase’s “Devices and cast” swaps the goal, role, opening, cast stances and suggested skills depending on state. Differences such as “while Daigo is bitten” or “after the medicine” no longer need a separate phase for the same place.

Variations are checked from the top, and the first whose conditions all hold takes effect. Empty fields keep the original, so write only what should change. The server decides which variation applies and the narrator only receives the swapped text. The opening is sent once, from the variation that applies when the player enters the phase.

Story-wide clocks

For deadlines and dangers that build over the whole story, use “Gameplay > Rules & checks > Story-wide clocks”. Set one once and it keeps the same value across every chapter and phase. “Every N actions” counts the story’s total actions, so the deadline keeps drawing near even through a run of short phases. The action-limit multiplier of the difficulty the player chose also applies, so easier levels take more actions to fill.

With mark names, the chapter tab shows “2 a.m. (4/8)” and the narrator gets the same time. An action budget such as 60 actions for the whole story works the same way: a clock with 12 segments that moves 1 every 5 actions. Players can spend the 60 actions across chapters however they like.

“How story-wide clocks move” under a phase’s “Devices and cast” adds rules that apply only while in that phase. Dawn can approach every 2 actions during a siege, or “Reaching the dock” can move on successful checks only on the north path, so each phase gets its own pace. A clock with no story rule that moves only through phase rules appears on the chapter tab once it starts moving.

Any phase’s transition can choose “When a story-wide clock fills” as its destination. Filling is recorded, so a phase entered after the clock filled meets that transition right away.

Clues

Place clues in a phase’s “Checks and clues”. “Opens when” is “On arrival”, “On a successful check” or “On a critical success”. Opened clues stay in the player’s chapter tab and reach the narrator too (up to 8).

The trick is three clues for each conclusion. If one is missed, the others still lead there. One on arrival and two on checks with different skills lets every play style move forward.

Encounter tables

An encounter table ties a lottery skill (an outcome table) to a phase. Create a lottery skill under dice checks, then in a phase’s “Devices and cast” draw it “every N actions”, “on arrival” or “on moving to a location” (up to 3).

Encounter tables are drawn on turns without a check, and the 🎲 line reads “The world moved”. The drawn result goes to the narrator, which works the event into the scene.

The stone corridor draws every 5 actions. A “nothing happens” row gives a rhythm of quiet turns and eventful ones.

Six kinds of transitions

In a phase’s “How to advance”, decide what leads to which phase. One phase can have several branches. Adding “At least N action(s) before advancing” gives the phase time to breathe.

A branch cannot go back to an earlier phase. To return to the same place, add it as a new phase.

Map connections

In “Gameplay > Map”, choose “Reachable from here” for each place (connections are one-way). Turn on “Limit travel to connected places” and both the player’s moves and the narrator’s scene changes stay on connections, giving exploration a route.

A chapter’s “Place on entering this chapter” and a phase’s “Place on entering this phase” set the current location. In the sample, chapter 1 starts at the management guild, moves to the first floor on entering the stone corridor and to the first-floor camp on entering the retreat.

No moving in this phase

Turn on a phase’s “No moving in this phase” and map moves and the narrator’s scene changes stop while it lasts. Use it for scenes the party cannot leave, such as combat. The sample uses it on “Ambush”. The player’s map shows why they cannot move, with the phase name.

Next chapter and endings

A phase without transitions is a terminal; reaching it ends the chapter. A terminal can pick the destination chapter in “Next chapter”, which defaults to the next chapter in order. Turn on “Make this the story’s ending” and play closes on arrival and is recorded as an ending.

In the sample, chapter 1 has two terminals, “Sealed iron door” and “Retreat”, both leading to chapter 2 (camp). In chapter 5, “Follow the gouges” leads to chapter 6 (the black dragon) and “Follow the smell” to chapter 7 (the mana-rot flower), splitting the route.

Handouts

In “Chapters > Rules for this chapter > Handout (read by the player only)”, write a mission or secret that only the player reads at the start of the chapter. It never reaches the narrator. The player enters the scene keeping the secret and chooses the moment to reveal it.

You are a recorder sent by the management guild. Your official task is to record the survey and assist Supervisor Ayame. But before you left, the guild master whispered one thing to you: “Two guild staff are among the missing. They are not on the list. If you find them, do not tell the others.”

Chapter directives

“Chapter directives (read by the narrator)” are instructions the narrator follows every turn while in the chapter. Write what stays the same through the chapter: how the setting looks, how strong the monsters may be, how close the cast members are.

“Behind-the-scenes setup (hidden from the character)” are used in stories with “Let the character drive the story” turned on in “Gameplay > Rules & checks > Game rules”. With it on, characters use the hidden truth as material to move the story on their own.

Action limit and hard stop

A chapter’s “Action limit” is how many actions the player gets in it. It drops by 1 per message, and also by 1 on a fumbled check. When it runs out, the narrator closes the chapter as the end of the day’s actions.

Turn on “Stop input when actions run out” and at 0 no new actions are accepted; only “Close the chapter” and “To the next chapter” remain. The chapter break becomes clear, and spending limited actions carries real tension. The sample’s chapter 1 has an action limit of 30 with this on.

What the player sees

Where each author setting appears on the player’s screen.

Design patterns

A template for one chapter

Five phases give one chapter the rise and fall of a session.

Giving the climax a “give up” exit by choice lets the story move on even after repeated failed checks. In chapter 1, “Give up on the door and camp” leads to the retreat phase.

A camp chapter

Put a short chapter without phases between exploration chapters. Leave the action limit empty and spend it on rest, conversation and preparation.

• State override: set stamina to 100 and the floor to “first-floor camp”.
• Restore skill uses: choose “All skills” to refill limited skills.
• Chapter directives: “no exploration or combat”, “conversation that brings the cast closer”, “close by confirming the will to go down to the next floor”.

Placed after a tense chapter, it becomes time to deepen relationships with the cast.

Branching chapters and endings

End a chapter with “When the player chooses” branches and give each terminal a different “Next chapter” to split the route. In the sample’s chapter 5, “Two trails”, following the gouges leads to the black dragon chapter and following the sweet stench leads to the mana-rot flower chapter.

In the final chapter, mark both the winning and losing terminals “Make this the story’s ending”. The sample’s black dragon chapter has both “Slain” and “Rout” as endings. Losing still closes as a story, so the player can take in the result and start the next run.

A combat phase

Build combat from two clocks and a movement lock.

• Enemies left = a progress clock: 1 on a successful combat skill, 2 on any critical. When full, go to the “fight through” phase.
• Wounds = a danger clock: 1 on any failed check. When full, go to the “fall back” phase.
• Turn on No moving in this phase so combat does not drift into another phase.
• Put fight, dodge and cast members’ big moves in Recommended skills, and the referee considers them first.

The sample’s “Ambush” uses golems left (2 segments) and wounds (3 segments). The final black dragon fight uses the dragon’s stamina (5) and the dragon’s rage (5), which also fills every 2 actions, for a long showdown.

Reading the pre-save checks

“Checkup” at the top of the Gameplay and Chapters steps and “Checkup for this chapter” in a chapter pick up settings that have no effect or that block progress, from saved content. “Warning” items are things that can trouble players; “Note” items are useful to know. Saving still works. Fix and save, and the checks refresh.

Dice are OFF but checks are used

Shown when a phase has clues opened by checks, clocks advanced by checks, encounter tables or “On a check result” transitions while dice are OFF. Set the play style to “Narrator asks for checks” or “TRPG (referee)” and check results move the phase on.

This phase cannot move on

Shown for a phase where no transition can fire, such as a phase whose only exit is “On a check result” while dice are OFF. Add one “When the player chooses” or “With ‘Next’” transition and the phase always moves on.

Actions run out before the terminal

Shown when “Stop input when actions run out” is on and the shortest path to a terminal needs more actions than the limit. As is, time runs out and play is sent to the next chapter before reaching the terminal. Levels that shrink the action limit are checked too. Raise the action limit or lower the phases’ minimum actions, and every difficulty can play through to the terminal.

Behind-the-scenes setup needs the director

Shown when a chapter has a behind-the-scenes setup and “Let the character drive the story” is off. Turn it on in “Gameplay > Rules & checks > Game rules” and characters use that setup to move the story. Put what the narrator must follow every turn in the chapter directives.

Choosing a difficulty changes nothing

Shown when difficulty chosen by players is set but neither the action limit multiplier nor the check adjustment takes effect, for example with no chapter that has an action limit and a difficulty model of “Skill value as is”. An action limit on a chapter makes the multiplier work; “Three tiers with modifiers” makes the check adjustment work. When only one of them works, it shows as a note.

The referee’s difficulty has no effect

A note shown when the timing is “Let the referee decide” and the difficulty model is “Skill value as is”. With “Three tiers with modifiers”, check difficulty follows the action.

A clock never advances

Shown for a clock with no advance rules, or one with a “When judged closer to the goal” rule while the referee is not used. Add an “Every action” or check rule and the phase moves on when the clock fills.

Move-based devices but no places on the map

Shown when there are “On moving to a location” clocks or “on moving to a location” encounter tables but the map has no places. Create places on the map and moving drives the story.

The last phase has no ending mark

A note shown when the story’s last terminal lacks “Make this the story’s ending”. With it, the player’s run records the ending.

An “End the chapter” threshold in a story without action limits

The threshold effect “End the chapter” sets remaining actions to 0 and carries the chapter to its close in chapters with an action limit. In chapters without one, it becomes a cue to the narrator. Give the chapter an action limit and the threshold closes it reliably.

A story-wide clock that nothing moves

Shown when a story-wide clock has no rule in Gameplay and no phase adds one in “How story-wide clocks move”. Add either and it works as a deadline.

A roll effect points to a field it cannot move / a field nothing moves

Shown when a skill’s “Change state by result” or a phase’s “Extra roll effects” points to a field that is not in the state fields (or is a text field). Pick a number, stage, yes/no or list field and each roll updates the state.

It also tells you when a field set to change only by the server is moved by no roll effect and no chapter or phase state override. Move it with either and players’ rolls and phase changes show up in its value.