In 2012, I adopted Emily Short’s Threaded Conversation extension for Inform 7. After reworking the code, expanding the documentation, and several rounds of testing, it’s ready for release.
In brief, TC provides a conversation system that tracks facts known, phrases spoken, and subjects of conversation for the Inform 7 language. It combines ask/tell style commands with hints to the player about what to say next, and provides extensive authoring tools for organizing and controlling the flow of conversations.
The latest version is now available on the Public Library built in to Inform 7. It is also available for Inform version 6G60 on the official Inform 7 old extensions page.
Also useful is the conversation builder, an optional accessory extension for Threaded Conversation, to help automate some of the more tedious parts of building a complex conversation with TC. Find it at either the link above or the Public Library, depending on which version of Inform you’re using.