Canvas

A wall of terminal text is a bad review surface, and over SSH even a beautiful HTML file is unreachable. The canvas fixes both: the page is served (any machine on the network can open it), the input lives on the page next to the thing being discussed, and the loop is live — submit wakes the agent, the agent acts, the page redraws. It turns "read my summary, then type your reactions back" into "look at it, comment where it's wrong, watch it update."

This is shared infrastructure, not a phase — a surface several skills sit on. In the better-planning family: brainstorm runs its one-decision-at-a-time loop on it, prd and plan serve their companions through it for review rounds, design walks the TDD layered-zoom (system shape → boundaries → decision) on it, sync serves its boundary digest (shape moves + forks) on it during the build, and comprehend draws the system's shape on it for on-demand catch-ups. study serves its interactive, recall-checked lessons on it. And it's just as useful standalone — explaining an architecture, walking a diff, comparing options, running a quiz — anywhere "let me show you" beats "let me tell you."

The mechanics