[FEATURE] Desktop: file upload in the in-app Browser (parity with Claude in Chrome's file_upload)

Preflight Checklist

• [X] I have searched existing requests and this feature hasn't been requested yet
• [X] This is a single feature request (not multiple features)

Problem Statement

The in-app Browser in the Claude desktop app has no way to attach a local file to a page's <input type="file">. Its tools (mcp__Claude_Browser__*) can click, type, fill forms, read the page and run scripts, but when Claude clicks an upload button the page opens the OS file chooser, and Claude cannot operate that dialog. Any web task that includes an upload stops at that step until I pick the file myself.

Claude in Chrome already has a file_upload tool for exactly this, so the gap is between the two browsers Claude can drive, not a missing concept.

Proposed Solution

Add a file upload action to the in-app Browser tools that matches Claude in Chrome's file_upload: it takes a reference to a file input (a ref from find/read_page) and one or more local paths, and sets the files on the input directly, without opening the OS file chooser (for example through the DevTools Protocol's DOM.setFileInputFiles). Reading the local files can go through the same permission prompt as any other file read.

Alternative Solutions

• Switch to Claude in Chrome for the upload steps: Works, but the task then runs across two browsers, and the in-app Browser session I already signed in to is no longer used.
• Pick each file by hand: Works, but turns an unattended task into one handoff per file.

Priority

Medium - Would be very helpful

Feature Category

Other

Use Case Example

1. I asked Claude to set up a game's listing on a creator dashboard in the in-app Browser. The images were already in the repository.
2. Claude created the badges, developer products and game pass and filled in every form field itself.
3. The listing needs 25 image uploads: 14 item images (9 badges, 4 developer products, 1 pass), the icon, and 5 thumbnails on each of two tabs.
4. Each upload became a handoff. Claude stopped and gave me a file path, I clicked the upload button and picked the file in the chooser, and then I told Claude to continue.
5. With this feature, Claude would set each file on the input itself, and the whole task would run without me.

Additional Context

• Claude desktop app 2.19675.0.0 (Windows 11), Claude Code 2.1.286.
• The equivalent tool exists in Claude in Chrome (file_upload), so the input shape could match it.