{"slug": "why-static-accessibility-scanners-miss-what-ai-agents-hit", "title": "Why Static Accessibility Scanners Miss What AI Agents Hit", "summary": "A developer reports that static accessibility scanners fail to detect issues that break AI agents in booking flows. Three patterns—non-dialog modals, missing live regions for errors, and keyboard traps in date pickers—all pass static scans but cause agents to fail silently. The post argues that dynamic interaction testing is needed to catch these state-dependent failures.", "body_md": "This button passes every automated accessibility scan we've thrown at it:\n\n```\n\n Check availability\n \n```\n\nAnd it breaks every AI agent that tries to book a room through it.\n\nThe markup is clean: a real ``\n\n, a proper accessible name from its text content, an explicit `type`\n\n. Nothing to flag. The failure isn't in the button, it's in what happens after the click. And no static scanner ever clicks.\n\nStatic accessibility scanners evaluate the DOM at a point in time. Usually the initial render: HTML parsed, framework hydrated, nothing interacted with. They check that state against WCAG rules, missing alt text, contrast ratios, label associations, heading order.\n\nThat's genuinely useful. It's also a photograph of a lobby, when the task happens in the hallways.\n\nHere's what never appears in the initial DOM of a typical booking flow:\n\nA scanner reports zero issues on all of these, for the simple reason that at scan time, none of them exist.\n\nAn AI agent completing a booking doesn't evaluate a snapshot. It walks the flow: reads the accessibility tree, decides on an action, performs it, waits for the interface to respond, reads the tree again. Every state transition is a place where the tree can lie to it.\n\nLet's look at three patterns we keep finding in real audits. All three pass static scans. All three stop an agent.\n\n```\n{isOpen && (\n \n
\n
Select your room \n \n
{error}
}\n