EDIT: From the looks of it, you have 1 weapon that has it's ingredients set up, but you don't have an item set up to act as that weapons recipe. You'll want to make an item that looks like this:
The portion of this image that pertains to your situation is the <Weapon Recipe: 1, 2, 3, 9, 11, 12, 15>
notetag. So when the player has this item in their inventory, they gain the ability to craft weapons 1, 2, 3, 9, 11, 12 and 15 from my database, which are all the melee weapons made from iron.
So, not only do craftable items(weapons and armor included) need to have a given recipe in their own notetags to denote which materials are used to create them, you also need to implement a separate item to give the player the ability to craft the items.
I did a test in another project before to craft this weapon:
Using these items:
and it all worked fine without needing a recipe item.
What's funny too is that the "Synthesis" command works fine for this project but doesnt even show up in the first one...
In your second image, you have a notetag <Weapon Recipe: 5>
If you compare that you your second image from earlier, for the bat fang, you will see that the two notetags are different. <Weapon Synthesis: 5> is incorrect syntax of yanfly's Item Synthesis notetags.
To clarify, in your second set of images, your "Stiff Lizard Tail" is your weapon recipe, as it has the notetag: <Weapon Recipe: 5> If the player has "Stiff Lizard Tail" in their inventory, they have the ability to craft Weapon 5, as listed in the database.
Also, if you are using Yanfly's Item Core plugin, you cannot use independent items as ingredients! Notice the <Not Independent Item> notetag on the attached image, highlighted in blue.
Your recipe is being consumed when you craft your weapon because it is also an ingredient. You've created a kind of loop. Also, without any recipes in your inventory, the crafting option does not show up in the menu. Yanfly coded his plugin this way intentionally.
The solution is to create a separate item to act as the recipe.
One method i use for testing purposes is to have a debug item that will not be available in the actual game that is a recipe for every item:
<Item Recipe: 1 to 2000>
<Weapon Recipe: 1 to 2000>
<Armor Recipe: 1 to 2000>
This item will act as a recipe for any item I make into a craft-able item later.
Correct, but it is also more than that. It is a tool for you, the developer so that you can always test your crafting system without having to make recipes for every craft able item just to test it out.
But in the actual game the player won't have that tool right? Is there a way I can keep the synthesis and the craft list available for the player just so they would be able to check it during the game?
And back. Trying to work online with no internet for 1.5 days was...interesting. I felt like a character in a old Sierra game trying to find internet due to all the hoops I had to jump through just to get online for work.
Designing patches that can 'augmented' to clothing based armor. Such good fun. A bit time consuming due to the need to create image displays, but the patches are limited so it's not too tiring.
Note: lol, posting this made me find a couple mistakes.