In this channel's material, the diff sidebar is the review surface of agent work: a side panel that lays out the changes a coding agent made as a diff, so a human can explore what was touched and verify it before accepting. It belongs to the recurring lesson of the topic — the human's job shifts from typing code to planning, orchestrating, and verifying — because reading the agent's diff is precisely the verify step. [^717e6970-382c-5199-9605-8fa2c37ec1b2@102] Whether the surface lives in a GUI (as with OpenAI's Codex app, described as a command center for agents [^01a0f15a-ae5e-7bde-ad5a-ca55ef1b1bb4@102]) or another interface, the practice is the same: use the sidebar's diff to understand the change, judge it against intent, and only then accept or send it back for another iteration. [^717e6970-382c-5199-9605-8fa2c37ec1b2@102]