Shard Tools

See what happens when a file stays in your browser

Run a real image resize. Inspect the output and the request count yourself, then see exactly where the browser-local promise ends and Edge Assisted MCP begins.

Try the browser-local workflow

Resize the sample image or one of your own. The output is a 200×200 JPEG created in this tab. We count data-capable requests before and after the resize.

The result appears here

Image preview, output size, and before/after request counts.

What the result tells you

The resize uses browser APIs to decode your image, draw it on a canvas, encode a JPEG, and create a temporary blob download. The counter reads Resource Timing entries for fetch, XMLHttpRequest, and sendBeacon immediately before and after the operation. An unchanged count means this run did not record an additional request through those APIs.

This is a visible check, not a proof about every possible browser request. Other page activity can add requests while the test runs, and Resource Timing does not inspect request bodies. For a closer look, use your browser's Network panel and check the destination and payload of any request that appears during processing.

Where your file goes

Browser-local tools

Files are selected and processed in your tab. The generated result is a local blob download. This demo follows that path and does not call /mcp.

Browser tool routes reject POST, PUT, PATCH, and DELETE with a 405 response.

Edge Assisted MCP

An AI assistant can send file bytes to /mcp using POST. Cloudflare processes them for that request and returns the result. The file leaves your device in this mode; it is not the browser-local workflow demonstrated above.

Loading a page still fetches HTML, scripts, styles, fonts, and sometimes processing models. AdSense and external directory badges can also appear as third-party hosts. The footer's live report lists those connections; they are separate from the browser-local resize.

Repeat the check in DevTools

  1. Open the browser developer tools and select the Network panel.
  2. Clear the request list, then run the sample above. Inspect any requests that appear.
  3. Repeat with your own image. The output should use a local blob URL, not an upload response.