[BUG]

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

Claude in Chrome cannot dispatch clicks into cross-origin iframes (e.g. Shopify App Bridge embedded apps)

### What Should Happen?

## Summary
Claude in Chrome cannot click or focus elements inside a cross-origin iframe embedded within a page — specifically, a third-party app (Goaffpro) embedded in Shopify's admin via App Bridge. This makes it impossible to automate any interaction with apps that use this very common embedding pattern.

## Environment
- macOS, latest Chrome
- Claude in Chrome extension, via Claude (Cowork/desktop app) browser automation tools
- Target page: `https://admin.shopify.com/store//apps//settings/...` (a Shopify-embedded third-party app rendered inside an iframe)

## Expected
The click registers inside the iframe (checkbox toggles, dropdown opens).

## Actual
Nothing happens. Diagnostics performed:
- `document.elementFromPoint(x, y)` confirms the IFRAME element is correctly the topmost DOM element at the click coordinates — rules out a coordinate/offset bug.
- Pressing Tab and checking `document.activeElement` shows focus lands on the parent page's own elements (e.g. its "Skip to content" link), never entering the iframe — indicating the click/focus event is not being routed into the iframe at all.
- Ruled out: browser zoom level (confirmed 100%, `visualViewport.scale === 1`), a full Chrome quit/restart, and extension site-access permissions (already "On all sites").

## What support told me
I raised this with Anthropic support. They confirmed this is consistent with a known limitation: cross-origin iframes often have no accessible node in the accessibility tree, so Claude works from screenshots and clicks by coordinate, and the executor (the extension) has to resolve which frame a coordinate lands into — which it currently cannot do across origins due to browser security restrictions. They could not share whether the click dispatch is implemented via synthetic DOM events (content-script `dispatchEvent`, which cannot cross origins) or via the Chrome DevTools Protocol's `Input.dispatchMouseEvent` (which operates at the browser-process level and generally *can* route into out-of-process iframes, since real user input relies on it too). They also had no documented workaround or roadmap item for Shopify/App Bridge specifically.

## Questions / feature request
1. Is click dispatch currently implemented via synthetic DOM events or via CDP-level input injection? If the latter, why does it still fail to reach the iframe here — is frame targeting not resolved for OOPIFs?
2. Is there any plan to support interacting with cross-origin iframes (e.g. by resolving the target frame via CDP and dispatching input in that frame's own coordinate space)? This would unblock automation for the very common case of Shopify (and likely other platforms') embedded third-party apps.

## Impact
Blocks any automation workflow that needs to interact with a Shopify-embedded (or similarly App-Bridge-style embedded) third-party app UI — this is a common integration pattern, not a one-off edge case.

### Error Messages/Logs

```shell

```

### Steps to Reproduce

## Steps to reproduce
1. Navigate to a Shopify admin page that embeds a third-party app via App Bridge (renders as an iframe).
2. Ask Claude to click a checkbox/dropdown inside that embedded app's UI.

### Claude Model

Sonnet (default)

### Is this a regression?

I don't know

### Last Working Version

_No response_

### Claude Code Version

N/A — not using the Claude Code CLI. This report is about the Claude in Chrome extension used via the Claude desktop app (Cowork).

### Platform

Anthropic API

### Operating System

macOS

### Terminal/Shell

Terminal.app (macOS)

### Additional Information

_No response_

No repository file, test, or entry point is identified. First confirm whether Claude in Chrome/Cowork is in scope for this repository, then trace the extension's click-dispatch path using the Shopify App Bridge cross-origin iframe reproduction. Done would require an agreed implementation path and a reproducible test showing clicks or focus reach the embedded app.

索引モデルが issue の本文から書いたものです。