EA has planned all along to release official mod tools for SimCity, and is now finally making that vague idea more concrete. Maxis has proposed basic guidelines for the type of mods it'll allow, and is polling the community for feedback. Surprise surprise, they're more restrictive you'd hope.

"Our goal is to ensure that we provide a place for all of our players to have fun while assuring them that the gameplay experience is safe and has integrity. It's difficult to determine what makes a 'good' or safe mod and what mods cross the line," Maxis said. It proposed these guidelines:

• Acceptable UGC and mods do not jeopardize the integrity of the gameplay or harm the experience of others.

• UGC that effects the simulation for multiplay games and features are not allowed.

• Examples of acceptable UGC include swapping art assets, like buildings and vehicles.

• Maxis reserves the right to take disciplinary action against players who break the rules.

Yes, given that all cities are connected online, anything which massively changes how one runs is likely to be disallowed. This is only the first draft, but so far it's looking pretty dull.

People have been modding SimCity for a while with self-made unofficial tools, and can already easily swap art. What would be of far more interest is wide, sweeping changes that can expand and rework the game. One early hacky mod added offline support and expanded building outside city boundaries, which is probably exactly the sort of thing EA intends to disallow.

Maxis does want feedback on how to handle mods, how to segregate modded cities, and how much mods should be able to change, so all this is not set in stone.