Implanted Weapon Spellbook

To attune to this item, you hold the weapon to your skin of your forearm, throughout the attunement process.
When the attunement is complete, weapon melds into your arm, which appears on the skin as pattern in the shape of the weapon.
If your attunement to the weapon ends, the pattern vanishes, and the weapon reappears in your space.

You can use a bonus action to summon the weapon, or dismiss it.
The base of this weapon contains a scrollcase, storing a special spellbook.
As an action, you can pull on the base and think of a spell you have written within the book or blank page, pulling a strip of vellum from the case with the intended page shown.
Additionally, you can conduct a 1 minute ritual to open the end cap of the case, and insert up to 100 rolled vellum pages into the case, that will be added to the spellbook within.
The pages must be blank, or from a spellbook you wrote, and can not be removed from the book after.
This weapon can be used as a spellcasting focus for your spells.

Notes: Spellbook User