An AI shopkeeper NPC for your Roblox game

A shopkeeper that actually answers questions about your items — "which sword is best against armor?" — feels alive in a way a static menu never does. Here's the minimal version.

Give the NPC your catalog

Put your item list in the system prompt so the NPC only talks about things that exist:

local ai = Cortex.new("YOUR_KEY")

local persona = [[
You are Marta, a cheerful blacksmith's apprentice. You sell:
- Iron Sword (balanced), Warhammer (slow, heavy damage), Dagger (fast, weak).
Answer player questions in one or two short, in-character sentences. Never invent items.
]]

local reply = ai:ask(persona, playerMessage)

Make it hold up in a real game

• Per-player memory so Marta remembers what a player already asked.
• A cooldown per player so nobody can spam her.
• Filter her replies before showing them.

With the Cortex kit that's an NPC object with memory and moderation built in:

local marta = ai:npc({ personality = persona, moderate = true })
local reply = marta:say(player, playerMessage)

Free and open source: https://github.com/cortex-rbx/roblox-ai-kit