Open a file in Obsidian.
If $ARGUMENTS is provided, open that file. Otherwise, look back through the conversation for the most recently referenced vault file path (e.g. from a Read, Write, or Edit tool call) and open that. If multiple files were created or edited in the same operation, open all of them. If no file can be found, just open the vault.
Use the Advanced URI plugin: open "obsidian://adv-uri?vault=YOUR_VAULT&filepath=<relative-path>&openmode=tab" where <relative-path> is the path relative to your vault root, including the .md extension. URL-encode spaces as %20.
When opening multiple files, issue separate open commands for each file. They will each open in a new tab.
If opening the vault with no file: open "obsidian://open?vault=YOUR_VAULT".