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This demo follows Codex as it investigates a spreadsheet bug using next-dev-loop and agent-browser. Changing a revenue value in one sheet leaves the chart in another sheet unchanged. The speaker introduces the skill in the context of Next.js 16.3 and says it directs a coding assistant to verify runtime behavior after editing app code. A successful build or type check alone would not catch the visible failure shown here.
The setup requires the agent-browser package. The speaker installs the skill and selects the default agents, then gives Codex a short description of the bug. Codex reads project files, opens a browser, edits spreadsheet cells and takes screenshots to check the chart. It repeats the reproduction across browser sessions before reporting a fix.
In the demonstration, changing cell B2 to 900,000 initially leaves the plotted point unchanged. After the fix, the speaker reports that the chart redraws correctly. He then manually tests another value, 915,000, and shows the corresponding point higher on the graph. The component takes several seconds to load, so screenshot timing matters. Interpreting a chart inside a screenshot also adds difficulty. The speaker suggests Claude Code should work similarly, but the demonstrated workflow uses Codex.
The creator discloses paid Kinde brand sponsorship and promotes his web development courses in the description. This is one demonstrated bug fix, rather than proof that browser checks catch every regression.
