How to play Ironsworn solo with an AI narrator

The one rule that makes this work

The model never decides an outcome. That's the whole discipline. An LLM asked to "roll" will produce whatever number best fits the sentence it was already writing, and it will do this even when you tell it not to. Once the dice are fictional, the tension is fictional, and a solo campaign with no real risk goes flat inside an hour.

Roll physically or in software, get the outcome tier first — strong hit, weak hit, miss — and only then ask for prose. The narrator's job starts after the dice have landed.

What to give the narrator every single turn

Most solo AI sessions fail at turn twenty, not turn two, and they fail for a boring reason: the model has stopped being told the things it needs to stay consistent. At minimum, each turn should carry:

• The roll that just happened — the move, the stat, the action score, both challenge dice, the outcome tier, and whether it was a match.
• Your current sheet — health, spirit, supply, momentum, conditions. A narrator that doesn't know you're at 1 health writes a scene that makes no sense.
• Named entities so far — every NPC, place, threat and vow, with one line each. This is the thing people skip, and it's the thing that causes the dead brother to walk back into chapter nine.
• Your open vows and their progress. Without them the story wanders, because nothing in the context says where it's supposed to be going.

What to never give it

• Authority over the fiction's facts. If the model invents a sister you never had, that sister is now canon unless something rejects her. Seal your setting truths before play and treat contradictions as errors, not as creative choices.
• The whole transcript. Beyond a few thousand words, dumping raw history makes recall worse, not better. Summarise into structured state — a ledger of entities and facts — and send that instead.
• Your next decision. The most common failure mode of AI narration is the model playing your character for you: "you draw your sword and charge." A narrator describes the world's response and then stops.

A turn loop that holds up over a long campaign

1. State your intent in one sentence. What are you actually trying to achieve?
2. Pick the move that matches the intent, and the stat that matches the approach.
3. Roll: d6 + stat + adds against two d10 challenge dice. Cap the action score at 10.
4. Read the tier. Beat both dice: strong hit. Beat one: weak hit. Beat neither: miss.
5. Apply the mechanical consequence — track changes, momentum, conditions — first.
6. Now ask for narration, handing over the roll, the updated sheet, and your entity ledger.
7. Write anything newly named into the ledger before the next turn.

Steps 5 and 7 are the ones people drop when they're doing this by hand in a chat window, and they are precisely the two that decide whether the campaign survives session three.

Misses are the content

Solo players new to Ironsworn tend to treat a miss as a failed turn. It isn't. A miss is the engine handing you a complication you would never have chosen, which is the entire reason you're rolling instead of just writing. If your narrator softens misses — "you fail, but luckily…" — instruct it to stop, or the campaign flattens into wish fulfilment.

How Markbound does it

Markbound automates the loop above. Dice are rolled in code in your browser with crypto-grade randomness, the sheet applies its own consequences, a structured Codex of every named entity is maintained across the whole saga, and only then is the narrator called — with the roll, the sheet and the Codex attached, and with no authority to change any of them. Setting truths are sealed before play, so invented canon gets rejected rather than absorbed.

Ironsworn is by Shawn Tomkin and is available under Creative Commons Attribution 4.0. Markbound is an independent tool and is not affiliated with or endorsed by its author.