Users of feature-rich tools like Excel often miss more efficient workflows, repeating tedious steps and making avoidable errors. Current approaches to helping them require either manual prompting, which is effortful for users, or automated logging, which is limiting for developers. We present InvisibleMentor, a system inspired by over-the-shoulder learning: it observes what users do, then shows them how to do it better. To do this, InvisibleMentor analyzes screen recordings with a vision-language model to reconstruct actions and context, then uses a large language model to generate vision-grounded task reflection, structured suggestions grounded in observed behavior. In a user study, participants found InvisibleMentor’s suggestions more clear, more relevant, and more useful than those from a prompt-based assistant, demonstrating that AI can do more than automate away work—it can help users master it.

End-user programmers opportunistically copy-and-paste code snippets from colleagues or the web to accomplish their tasks. Unfortunately, these snippets often don’t work verbatim, so these people—who are non-specialists in the programming language—make guesses and tweak the code to understand and apply it successfully. To support their desired workflow and facilitate tweaking and understanding, we built a prototype tool, TweakIt, that provides users with a familiar live interaction to help them understand, introspect, and reify how different code snippets would transform their data. Through a usability study with 14 data analysts, participants found the tool to be useful to understand the function of otherwise unfamiliar code, to increase their confidence about what the code does, to identify relevant parts of code specific to their task, and to proactively explore and evaluate code. Overall, our participants were enthusiastic about incorporating TweakIt in their own day-to-day work.