Coding agents are getting runtime sight, and it's becoming table stakes.

The throughline across chrome-devtools-mcp 1.0 and browser-automation kits is agents that can observe what their code actually does at runtime: inspect a live DOM, read console and network, run Lighthouse, instead of only emitting source (Chrome for Developers). This closes the verification gap that makes agents confidently ship broken UI. I expect "the agent can see the running app" to become a baseline expectation for front-end work the same way file search became standard. If your agent writes UI it never looks at, you're debugging its hallucinations by hand.