Spark CLI Skills 1.3.1

Updates the use-spark base skill to Spark CLI 1.3.1.

Draft improvements

• draft --reply-all — reply to everyone on a thread (To + Cc, minus your address).
• draft --delete — permanently discard a draft (no Trash, no undo).
• draft --attach-id — copy an attachment from an existing email onto a draft.
• draft --attach-stream / comment --attach-stream — attach a file piped from stdin when the app cannot read the path directly.
• draft signatures — list the signature each mailbox appends.

Skill guidance

• Documents Reply-To handling, mandatory thread reply semantics, and that Spark appends account signatures automatically.

MCP tools

• Adds reply_all and delete parameters to the draft tool.