Aaron A. Reed recently announced an open beta for his Intelligent Hinting extension for Inform 7. This is an amazing extension that intelligently figures out how to solve puzzles in Inform 7-based games with high-level puzzle annotations in your I7 project.

You have to define "puzzles" and "tasks" in your own game, at implementation-time, and the extension provides a >SUGGEST command which indicates the next action to be taken to solve the current puzzle. It's surprisingly smart: if you've defined that a cloak must be placed on a particular hook, it will automatically figure out how to move the player to find the cloak, pick it up, and move the player to the hook. Not only that, it even knows how to completely automatically find keys for locked doors that are between the player and either the cloak or the hook.

Not only is this a good feature for end-users, it also offers very important benefits to implementors of IF: It makes it trivial to automatically test if your work is winnable, and it makes it similarly trivial to generate a walkthrough to publish with your game automatically.

Inform 7 has a rich and descriptive world model, and it's great to see tools that are starting to really take advantage of it in very useful ways.