From anything else: a list of links
If your old tool can export links, or you kept them somewhere, the link-list importer takes them: a Raindrop, Instapaper or Pocket export, any CSV with a URL column, or plain text with one URL per line. Up to 500 links go in per import, and BrainTube saves, transcribes and indexes each one.
What you get after the move
In Claude.ai you add BrainTube as a custom connector and sign in with OAuth, with no key to paste. Claude can search what you saved and save new things into it, on every plan including Free. In BrainTube's own chat, a video citation shows the timestamp of the moment it came from. Other MCP clients use the same endpoint; ChatGPT support is in testing.