Troubleshooting

Agent and pairing#

My agent has no genmc_pair tool. genMC is not added to the agent yet, or the MCP connection failed when the agent started. Add the server URL as described in Connect an agent, reconnect it in the agent app, then start a new chat or session.

"This code is unknown or expired". Codes work once and only for 10 minutes. Choose New code in the agent column.

The agent is connected but nothing happens. The agent only works while its app runs a turn. Check its chat; if it stopped, paste the wake-up prompt (see below) or simply tell it to continue.

My request stays Queued. No agent is listening right now. Choose Copy wake-up prompt in the notice above the input and paste it into the agent's chat. × takes unread requests back.

The agent's edits are rejected ("stale revision", conflict). You or another tab changed something in between. That is a safeguard, not an error: the agent reads the current state and continues. Avoid pressing Undo while the agent is working; in the build studio genMC asks first.

The agent talks to genMC with its own script and gets "403" or a stream it cannot read. Scripts need a User-Agent header (curl sends one) and should send Accept: application/json to get plain JSON answers instead of an event stream. Studio tools are called directly by name; genmc_call takes { name, input }.

The agent works in another tab. Each tab has its own pairing. A duplicated tab does not take over the agent. Pair again from the tab you want.

Saving and your work#

"Save a copy" appears. Another tab or device saved this document in between, so your save was refused instead of overwriting it. Save a copy keeps your version as a new document.

A new tab shows an empty skin or build. What you were working on is still open in your other tab, so the new tab started its own. To open it here anyway, pick it with the arrow next to the name. A reload keeps the tab's own skin or build.

My skins or builds are gone. Without an account, your work is tied to this browser's cookie. In a private window, another browser or after clearing site data, it is not reachable. If you signed in before, sign in again. Otherwise, re-import any exported files. See Storage and privacy.

"Maximum 1000 build projects". Delete builds you no longer need in the build switcher.

Exports and Minecraft#

The .mcfunction export is refused. The build would need more than 65,536 commands. Use the .schem export with WorldEdit.

Blocks appear in the wrong place in Minecraft. The function is placed relative to the position where you run it: use /execute positioned x y z run function … with the lowest corner where the build should start. Empty cells keep the existing world unless you exported with Clear the plot before placing.

My skin looks wrong in Minecraft. Check the model: a Slim skin must be uploaded as Slim (3-pixel arms), a Classic skin as Classic.

The tour video option is greyed out. It needs a room tour planned by the agent and a browser that can encode video (current Chrome or Edge).

Performance#

Large builds are slow. Hide or isolate parts in Details → Structure, use the slicer to cut away what you don't need, and close other heavy tabs. Very large builds load best on a desktop computer.

The page asks me to reload. After an update, old tabs must reload once to talk to the new version.

Send feedback#

Menu → Feedback sends a message to the genMC developer – a problem, an idea or anything else, optionally with an e-mail address for a reply. The current page path is included; no build contents or screenshots. Feedback does not reach your agent.