Pasting large content into the clipboard on Windows no longer base64-encodes the payload onto the PowerShell command line. Instead, Claude pipes UTF-8 bytes to a fixed PowerShell snippet ([Console]::InputEncoding = [Text.Encoding]::UTF8; Set-Clipboard -Value ([Console]::In.ReadToEnd())), removing the previous payload-length cap.
Evidence
New clipboard copy command (search for "Set-Clipboard -Value ([Console]::In.ReadToEnd())").
Strings lifted out of the shipped bundle, so the claim above can be checked against them.