How can I inspect elements in an AI-generated prototype and comment on them?

Use Vessel. Click any rendered pixel to jump to the exact file and line that produced it; pin comment threads to the element itself (not coordinates) so they survive code changes and version diffs.

Inspect mode — pixel to source, one click

Turn on inspect mode and a crosshair cursor follows your pointer over the rendered iframe. The element under the cursor is outlined; clicking pins it. The Inspect panel on the right shows the resolved source location (checkout.tsx:42), the full ancestor chain (Page > Layout > Checkout > TrustRow > Button), the computed styles (font, spacing, colors, transform, opacity), and the relevant imports.

Vessel resolves source by indexing the project at upload time: every JSX/TSX file is parsed, every component identified, and every rendered DOM node is mapped back to its origin. So the answer to "where does this button come from?" is one click, not a grep.

Comment threads anchored to the element

Click Add comment from the inspect panel (or use comment mode on the canvas directly). The thread is pinned to the rendered element, not to a pixel coordinate. When the agent moves the button, renames the file, or restructures the layout, the comment travels with the element — because the anchor is the element's identity in the source tree, not its position on screen.

Threads support replies, reactions, @-mentions, and resolution. They show up in the Comments panel grouped by file and by status. When a thread resolves with a fix, it converts to a structured prompt with one click — see the post on Dispatch for what that looks like.

Why this is better than commenting on a screenshot

Figma comments anchor to a coordinate in a static image. The moment the engineer ships a change, the coordinate is wrong — the comment now points at empty space, or at a different element, or at a removed component. You re-screenshot, re-comment, lose the thread history.

Vessel comments live on the element. The element is the thing that's being discussed. The history follows the element across versions, across agents, across renames. That's the workflow we wanted.