Craft GM Harness 2 Explained: What Changed, What Players Will Notice, and Whether Your V1 Game Is Safe (2026)
Craft GM Harness 2 is Craft’s rebuilt game master: the layer of code that reads your move, looks things up, rolls dice and writes the reply. Craft shipped it on 29 October 2026 and followed it with three patch notes in five days. If you play or build on Craft, four things matter: turns are meant to be much faster, the game master now reads a connected map, you can inspect any turn to see its working, and the date by which old games had to move to V2 was pushed back on 2 November.
Disclosure: Craft’s developers gave us closed-beta access and a subscription for our first look and review. No conditions were attached to our coverage, which is independent and unpaid.
What this page is, and is not. We read Craft’s patch notes B0.050, B0.051, B0.052 and B0.053 on 4 November 2026. We have not played Harness 2, we have not retested any of it, and our review of Craft was written before it. Every number about speed, memory and player activity below is Craft’s own claim, marked as such. Where this page adds a view of its own, it says so.
The Short Version
| Question | Answer, as of 4 November 2026 |
|---|---|
| What is it? | A rebuilt Game Master, called GM Harness 2, released 29 October 2026 |
| Faster? | Craft says turns are typically 10 to 20 times faster, and up to 60 times faster in some games |
| Better memory? | A new native memory system that uses vector embeddings. Craft says perfect long-term memory is “really hard” and that you should not expect it |
| Can I see what the GM did? | Yes: the Inspect turn feature, from the three dots menu on a reply |
| Will my V1 game be unlisted on 15 November? | The 29 October note said so. The 2 November note says Harness 1 support is being extended, with no end date yet |
| Is it finished? | No. Craft says it is early and has rough edges, and that rules-heavy worlds are the weak spot |
What Is a “Harness”?
A game master built on an AI model is more than a prompt. Between you and the model sits a working layer that decides what the model is shown each turn, which tools it can call (look up a place, roll a die, change your gold), and what gets kept for next time. Craft calls that layer the harness. Harness 1 was the first version. Harness 2 replaces it.
Why it matters to a player: the harness, not the model, decides how long you wait, how much the game master remembers and whether a change to your health is recorded or only described. When Craft says the harness is rebuilt, it is describing the part of the game that you feel as speed and consistency. Our Craft review found the waits to be the platform’s biggest cost, so a claim of 10 to 20 times faster turns is the one to test first.
What Changed for Players
These are the changes in Craft’s B0.050 note of 29 October, as Craft describes them.
- Speed. Turns are typically 10 to 20 times faster, and up to 60 times faster in some games. Craft says the research the game master does before narrating now takes seconds.
- Travel and maps. The game master reads a world’s maps as a connected graph of places, exits and distances, so it can tell you how far somewhere is and what lies on the way. Creators can mark exits, set up Transport locations for ships and caravans, and use Linked locations. Craft says the story now plays out on the map.
- Memory. A new native system uses vector embeddings instead of the file-based memory builders used before. Craft says it aims to recall details from thousands of turns back. It also says plainly that “it’s really hard to get perfect long-term memory”, that you should not expect perfection, and that it will use beta testing to collect data on campaigns of 1,000 turns and more.
- Game state. Changes to health, gold and items are recorded as they happen. A What changed card sums up health lost or gained, items gained or lost and objective updates. If you edit something by hand between turns, that edit is passed to the game master before your next move.
- Inspect turn. From the three dots menu on a reply you can see the rules the game master used, what it looked up, its dice rolls and what it changed.
- Trackers. Every world includes Time, Objectives, Combat, Party and Death saves where they apply. Creators can add their own trackers from templates or from scratch.
- Images. The Image Bank is free by default. Creators and players can switch to their own image model, which is billed per picture.
- Play settings. Response length, story pacing and long-distance travel can be set in Game settings and changed mid-game in Quick settings.
Our reading. Most of this list is about two things a player can check for themselves: whether a turn comes back quickly, and whether the record of what happened matches the story. The Inspect turn and the What changed card are the useful part. They let you test Craft’s claims on your own game instead of taking them on trust, which is how we would test it too.
What Changed for World Builders
- Triggered GM Instructions rise from 20 to 100 per world, and creators get custom player options.
- Systems must be upgraded before new games can be created from them.
- B0.051 (29 October) put Orbit, Craft’s world-building assistant, into Harness 2, and moved settings around. GM instructions now live under Settings, Game Master. Chat-only mode is under Player Preferences, Display, and the GM’s views have their own tab with a crowned die icon. NPC dialogue now appears inside the game master’s message in chat-only mode, not as separate bubbles.
- The conversation history slider is gone. In its FAQ, Craft says Harness 2 sends the game master as much history as fits in the compaction window. It says instruction caps are unlikely to rise and that pinned or partial files will not return. It suggests situational instructions instead.
- B0.052 (30 October) added a Settings tab for the GM’s name, portrait, voice, model and tools, a view of the GM’s full system prompt (Craft’s own sections hidden behind a toggle), a turn inspector that shows the system prompt and game state at the start and end of each turn, and an Appearance tab with 30 genre-grouped theme presets and 166 fonts. It also added numbered GM questions: a world with the Ask question tool turned on can offer numbered choices, which you pick by number or answer in your own words.
- B0.053 (2 November) added the three controls described in the next section.
Key Fields, Procedures and the File Tree
Craft’s B0.053 note explains something every builder will hit: why the game master sometimes forgets a character sheet it read a moment ago.
Craft says it removes research and read results from the context at the end of each turn, to keep turns cheap. A sheet the game master read on turn 12 is not in front of it on turn 13 unless something keeps it there. Three controls decide what stays.
| Control | What it does | Limits Craft states |
|---|---|---|
| Key fields | A file-type field marked as a key field stays in context across turns. Appearance fields and descriptions are key by default | Mark only a few. Long fields such as inventories cost context every turn |
| Procedures | A new kind of instruction for longer rules, with a Pruned setting: After use (dropped at the end of the turn, recommended for most) or On compaction (kept until the game’s memory is compacted, for a task that lasts several turns, such as a whole fight) | Up to 10,000 characters each and 25 per game |
| File tree | The game master now sees your folders and file counts, and can list and read files | Each read is capped at 12,000 characters, and large files are read in parts |
Craft also says it moved its own rules for travel, fights, trackers and hidden things into procedures, which cut the system prompt by about a quarter. The game master can now keep hidden notes, private to it, which you can open from the Hidden notes button under a reply.
Craft’s own advice is to start with a small, blank project, test one procedure or one situational instruction, and use the turn inspector to see how the game master behaves. That is good advice for any change to a game master, on any platform.
V1, V2 and the Deadline That Moved
This is the part most likely to matter to you tonight if you run a game on Craft.
| Date | What Craft said |
|---|---|
| 29 October (B0.050) | Existing games stay on V1 until 15 November. After that, projects not updated to V2 are marked unlisted, and remaining games must be updated to V2 |
| 30 October (B0.052) | Craft says some players with complex, rules-heavy systems are struggling with Harness 2, and it is working on adjustments. It scheduled two Discord town hall calls, on 30 and 31 October |
| 2 November (B0.053) | Craft says Harness 2 works well for casual players and world builders but has been weaker for power users, and that it is extending Harness 1 support. “There’s no specific timeline yet”, and it will give a heads-up before replacing Harness 1 |
What this means: the 15 November date was stated on 29 October, and the 2 November note says Harness 1 support is being extended with no date. B0.053 does not mention 15 November, so we cannot say for certain whether the unlisting still happens on that day. If your game is on V1, read the newest patch notes on Craft’s site before 15 November, and ask the community if it is still unclear. Our own digest of 3 November repeated the 15 November date, which the 2 November note then made out of date, and we have added a dated note to it.
The same 30 October note also gives Craft’s early numbers. It says existing players were taking about 49% more turns and playing about 29% longer, and that new players were taking about 45% more turns than the week before. Those are Craft’s own figures, and we cannot check them. They sit next to its admission that rules-heavy worlds were struggling, and the 2 November note is where Craft acts on that.
Who Should Move to Harness 2 Now
This is our view, based on Craft’s own description of its strengths and weak spots, not on testing.
- Casual players and story-first worlds: Craft says Harness 2 works well for you. If your problem is long waits, move and test.
- Worlds with long, strict rules, many trackers or a custom system: Craft says these are where Harness 2 has been weaker. With Harness 1 support extended, you have time. Test on a copy first, and use the turn inspector.
- Anyone who plays a long campaign: the memory claim is the one to test for yourself. Play past turn 100, ask about a minor detail from turn 5, and use Inspect turn to see whether the game master looked it up.
- Players of someone else’s world: you cannot move a world you do not own. If a favourite world is still on V1, the creator has to update it.
What We Have Not Verified
- Any speed figure. Our review found waits to be Craft’s biggest cost. We have not timed a Harness 2 turn.
- Memory at 1,000 turns or more. Craft itself says this still needs beta testing.
- Whether turns on cheaper and on stronger models differ in the way Craft describes.
- Whether a V1 world is still unlisted on 15 November.
- Multiplayer, scripting and better music and speech. Craft lists them as planned next, and none has shipped.
We plan to retest Craft in our quarterly pass. Until then, treat this page as a reading of what the developer says, with the claims marked.
Frequently Asked Questions
What is Craft GM Harness 2? It is Craft’s rebuilt game master, released on 29 October 2026 in patch notes B0.050. Craft says it rewrote the Game Master from the ground up, with turns that are typically 10 to 20 times faster, a native memory system, a connected map, and tools that record health, gold and item changes as they happen.
Will my old Craft game stop working on 15 November? Not on that date, as far as Craft’s latest notes say. The 29 October note said existing games stay on V1 until 15 November and that projects not updated to V2 would then be marked unlisted. On 2 November, patch notes B0.053 said Craft is extending Harness 1 support, with no specific timeline yet, and that it will give a heads-up before ending it.
How do I see why the Craft GM did something? Open the three dots menu on a reply and choose the turn inspector. Craft says it shows the rules the game master used, what it looked up, the dice it rolled and what it changed. Later notes added the system prompt and the game state at the start and end of the turn.
Does Harness 2 have perfect long-term memory? No, and Craft says so. Its note says it is really hard to get perfect long-term memory and that players should not expect it. Memory now uses vector embeddings to recall details from thousands of turns back, and Craft says it will use beta testing to gather more data on campaigns of more than 1,000 turns.
Why does the Craft GM forget a character sheet it just read? Craft says it removes research and read results from the context at the end of each turn to keep turns cheap. A world builder can mark a file field as a key field, which keeps it in context across turns, but long fields such as inventories cost context every turn.
Have you tested Harness 2? No. This page is built from Craft’s patch notes read on 4 November 2026. Our Craft review was written before Harness 2, and every speed and memory figure here is Craft’s own claim.
Craft is a third-party platform. Arcanum is independent and unaffiliated.