[BUG] claude-in-chrome: file_upload (DOM.setFileInputFiles) rejected with "Not allowed" on certain file inputs

Summary

When using mcp__claude-in-chrome__file_upload to upload a file to a programmatically-revealed <input type="file">, the wrapper rejects with CDP error {"code":-32000,"message":"Not allowed"}.

Reproduction

1. Navigate to a page with a file input that is revealed dynamically (example: note.com editor's eyecatch image input #note-editor-eyecatch-input).
2. Click the UI element that injects the file input into the DOM (example: the 「画像をアップロード」 menu button).
3. Capture the file input ref via find or read_page.
4. Call mcp__claude-in-chrome__file_upload with that ref and an absolute path to a local image.
5. Result: Failed to upload file(s): {"code":-32000,"message":"Not allowed"}.

Expected

The file should be set on the input (equivalent to raw CDP DOM.setFileInputFiles succeeding for an authenticated automation context).

Actual

The wrapper rejects with -32000 Not allowed. Raw CDP DOM.setFileInputFiles is documented to support this case in the protocol spec, so the rejection appears to be a wrapper-level restriction rather than a Chrome/CDP limitation.

Workarounds attempted

• JS-based input.files = dataTransfer.files followed by input.dispatchEvent(new Event('change', { bubbles: true })). The change event reaches the DOM, but the host page's uploader state machine does not transition because it expects the browser-native upload flow that completes via the OS file picker dialog.
• We plan to try (in priority order):
• (a) Input.dispatchDragEvent for a dragenter → dragover → drop sequence on the dropzone.
• (b) Native click on the upload button (open the OS dialog) followed by DOM.setFileInputFiles to satisfy it.
• (c) ClipboardEvent('paste') with an image blob into the eyecatch modal.

Feature requests (either is acceptable)

1. Document the conditions under which file_upload is denied and provide a sanctioned opt-in for trusted automation flows. Today the rejection is opaque to the caller.
2. Expose Input.dispatchDragEvent (drag-and-drop simulation) as an MCP tool. Many modern web apps treat drag-and-drop as the canonical alternative entry point for file uploads, and this would let automation flows recover without depending on DOM.setFileInputFiles.

Environment

• Chrome stable, macOS
• claude-in-chrome MCP extension (installed via Claude Code)
• Reproduces against any host page where the file input is gated behind a programmatically-injected DOM (note.com editor is one concrete case).

Why this matters

The file input upload path is currently the only blocker on a fully automated note-publishing skill we are running. With either of the two feature requests above, automation can complete end-to-end without manual intervention on the eyecatch / header-image step.