file_upload tool rejects local filesystem paths despite schema advertising them

Bug Description

The file_upload Claude-in-Chrome tool fails when provided with absolute local filesystem paths, despite its schema explicitly stating they are supported.

Schema (as advertised)

Tool description: "Upload one or multiple files from the local filesystem to a file input element on the page... The paths must be absolute file paths on the local machine."

paths parameter description: "The absolute paths to the files to upload. Can be a single file or multiple files."

Actual Behaviour

When calling file_upload with an absolute Windows path, the tool returns:

file_upload no longer accepts host filesystem paths. The MCP controller must read the file and pass its contents via the `files` parameter. If you are seeing this in Claude Desktop, update the desktop app.

Impact

The tool is advertised as enabling direct disk-to-browser file uploads with no token cost. Because the runtime rejects host paths, the MCP controller (Claude Code) is forced to read the file into context first — defeating the purpose entirely.

Environment

• Claude Code CLI (not Claude Desktop)
• Windows 11 Enterprise
• claude-in-chrome MCP extension

Expected Behaviour

Either:

1. The paths parameter works as documented (accepts absolute local filesystem paths), or
2. The schema and description are updated to reflect the new files parameter API, with clear documentation on how to pass file contents from the MCP controller side.