whats the purpose of this?
the default library already syncs across saves and servers, even cloud saves in steam and doesn't need mod support to work at all, meaning it works in any game you join.

the blueprint library has one fatal flaw: it has almost no modding support. you can not detect when the player opens or closes something, book entries can not be reordered, your personal library can not be changed at all, ...

for mods which improve blueprint handling like my sorting mod, the blueprint library is utterly useless. the player would have to constantly move stuff between the library and his inventory to use most of the functionality of those mods.

i asked the devs if they could improve the modding support of the blueprint library to no avail. the rewrite would be to massive and it is working "as intended".

so, i made this mod, because i want to have a blueprint library which offers full modding support.

mods not being able to mess with the blueprint library however is also one of its big upsides. Its neutral to mods, it doesnt care that a blueprint has a modded entity in it, it just saves the blueprint. if a mod is no longer there the blueprint can still be used. no mod can delete or move stuff in your library, its secure. It works without any mods, meaning you can join anyones game and it simply works.

Your mod makes a player dependent on your mod to even use the blueprints.
"oh wait, I go grab my blueprint"
log out of the game.
start own savegame
copy blueprint into blueprint library.
close single player.
rejoin multiplayer session.
Thats not a workflow that any mod should force onto a player.

And as a modder myself on other games, yes it looks good on paper to you because you made it. But one update can break the mod and then everyone using it for their blueprints loose access to their blueprints until you fix it. But if you dont play factorio anymore in half a year, what then? Factorio being factorio its unlikely that an update can cause this, but that's an universal concern when modding any game.

I don't want to down talk your mod, it sure is something unique. I haven't seen a mod doing anything similar, even working across savegames. But to me this mod looks like a total pitfall trap while the existing blueprint library perfectly suits all needs and only needs a bit work in usability.

mods not being able to mess with the blueprint library however is also one of its big upsides.

i am confused by this. since when can mods do something without players explicitly searching for them and installing them? you may create mods with misleading descriptions, but i am sure the devs will delete those after a few complaints. i do not think ignoring explicit player intentions is an upside. if players would not want a mod to change stuff inside their blueprint library, they would not install that mod.

Your mod makes a player dependent on your mod to even use the blueprints.

not really. my mod only does the sync and hotkey. the book will stay in your savegame even if you uninstall my mod. my mod also creates backups, which can be imported the normal way without my mod. so, even if my mod breaks you will not loose access to your blueprints.

... the existing blueprint library perfectly suits all needs and only needs a bit work in usability.

if the blueprint library would suit my needs, i would not have made this mod. i want a blueprint library where stuff is automatically sorted. and since the devs made it abundantly clear to me, that the blueprint library will not have this feature, i made my own fake blueprint library. to meet my needs, a bit work in usability would explode in a complete rewrite of the blueprint library. and since there are not enough complaints about the limited usability of the blueprint library, i reckon the devs do not even consider a rewrite.

you are right, the blueprint library has several upsides over my fake:
1. it is integrated into the game, you have access to your blueprints in every save and on every server.
2. since i am to lazy to parse the export string, the blueprint library is the only way you can keep data from unavailable mods.
3. item descriptions are not accessible by mods, so my mod can not sync them.
but there is one crucial feature my fake provides, that is not possible for the blueprint library: my fake offers full modding support, since it is an actual item in the gameworld.