We Kept Rebuilding Our AI Agent. Here's What Survived - Fuad Ali, Arize AI

Arize's in-product agent Alex went from a 2023 prototype that was "50% hallucination" to a single agent with planning, memory and on-demand skills, all built with custom harness code instead of a framework. AI PM Fuad Ali covers each decision: moving the plan into the harness, making "finish" an explicit gate, treating large tool results like files, why one 8,000-character memory file per user beat vector stores and knowledge graphs, merging 10 specialists into one agent, and using production sessions as tests. Chapters: 0:00 Intro 0:53 Agents all the way down 2:56 What Alex does 4:15 Timeline