You can convince peaceful intelligent monsters to join your cause (taming them) by chatting with them. The outcome depends on several factors: your respective alignments (lawfuls have a very hard time recruiting chaotic monsters), respective levels, respective races, your Charisma (which should be a large factor), and possibly others. Failing might turn the monster hostile, or do nothing. You only get one attempt per monster; if they don’t want to join you, trying again will never work. More complex behavior could possibly be implemented with the monster demanding something from you or making you do something before they will follow you. E.g. “I’ll only join you for 100 zorkmids,” or “Bring me the helms of three goblins to prove your worth!”

Internally, this would probably work by having a new flag “recruitable” on a monster, which is only set to true when a monster generates as peaceful (and is not set at all for certain monster types like shopkeepers and priests). Chatting first checks this flag: a taming attempt is only made if it is true, and it is set to false regardless of the taming outcome. Some peaceful monsters of a recruitable species could also generate with the recruitable flag as false.

To avoid this conflicting with existing #chat, there are a few options:

• Recruitment attempts only happen when you use the m movement prefix before chatting. This has the disadvantage of not being very discoverable.
• Chatting to recruitable monsters could bring up a menu of possible things to discuss with them, one of which is recruiting and another of which is regular chatting. This has the advantage of being extended to other possible interactions in the future.
• After the regular chat interaction occurs, you are asked if you would like to try recruiting them. There could be an option that disables this prompt.