What the channel means by core interaction In this channel's material on building AI products and startups, core interaction names the one interaction a product is built around — the action users take again and again that makes the product sticky [^e780a42f-b16e-5a92-b18c-685de50ce822@0]. The founders profiled in this chapter — behind products like Granola — treat finding this interaction as a distinct step in the journey from a fuzzy AI product idea to a validated, defensible business: it sits between building fast and surviving the industry's structural pressures, and it is what makes people come back rather than try the product once [^e780a42f-b16e-5a92-b18c-685de50ce822@0]. How it is used in practice The material frames it as something you find and validate, not something you assume [^e780a42f-b16e-5a92-b18c-685de50ce822@0]:- Identify which single interaction delivers the product's core value.- Test whether that interaction is sticky — whether users repeat it on their own.- Build the rest of the product around it, so growth and distribution amplify the thing that already keeps people engaged. - The core interaction is the repeatable action at the heart of a product, and stickiness is the test of whether you have found it.- In this chapter it is treated as a discoverable, validatable step in building an AI startup — demonstrated by founders such as Chris Pedregal of Granola, not generic advice.- Exploring the chapter's patterns is meant to help you plan and validate your own AI product idea with concrete evidence of what keeps users engaged.