Custom Item components such as "item_model" and "asset_id" from a datapack do not work on bedrock/geyser

[rotfloldude]

Describe the bug

Making any custom items and assigning an item model or asset_id from a datapack works flawlessly in java but in bedrock such changes to the items appearance through the aforementioned methods does not change them on bedrock/geyser

To Reproduce

1. Create a datapack for a custom recipe with the correct folder structure (New Datapack\data\datapack_name\recipe\items)
2. Create a .json file for a new recipe and add it to the recipe\items folder
3. Example crafting recipe with custom components looking like this: https://misode.github.io/recipe/?share=zy7mUOWvgh
4. Notice the newly added correct components "asset_id" and "minecraft:item_model"
5. Run the game/server login and join
6. Works perfectly as a java user, you can see the item model and asset is changed
7. Run and join through Bedrock, it appears to remain the same as if the item was not modified at all

Expected behaviour

Expected that the item components on the item would appear as they do on java, such as the appearance of items through minecraft:item_model or asset_id through the equippable component

Screenshots / Videos

Screenshot from Java, Inventory

Screenshot Left Java, Right Bedrock

Server Version and Plugins

Paper version 1.21.4-128-main@7e21cb8 (2025-01-26T22:08:28Z) (Implementing API version 1.21.4-R0.1-SNAPSHOT)
You are running the latest version
Previous version: 1.21.4-121-88bbead (MC: 1.21.4)

Geyser version 2.6.0-b751 (git-master-5836dab) (Java: 1.21.4, Bedrock: 1.21.40 - 1.21.44 - 1.21.50 - 1.21.51)

Geyser Dump

https://dump.geysermc.org/kPrpuH6vD0pyteiRs2yUFXrgXDRoPAov

Geyser Version

Geyser version 2.6.0-b751 (git-master-5836dab) (Java: 1.21.4, Bedrock: 1.21.40 - 1.21.44 - 1.21.50 - 1.21.51)

Minecraft: Bedrock Edition Device/Version

1.21.51

Additional Context

No response

[eclipseisoffline]

Hi, custom items added through datapacks or mods have to be registered in Geyser using item mappings or the custom item API. A PR (#5189) is currently open to extend the custom item API to incorporate for components like minecraft:item_model and minecraft:equippable. If you'd like to see how registering custom items with that PR will work, feel free to take a look at this repository.

Note that custom equipment models (that the asset_id property uses in minecraft:equippable) require attachables instead on the bedrock resource pack. This is illustrated in the repository mentioned above.

Custom items in 1.21.4 can still make use out of the current custom item API, but with a workaround. Feel free to join the Discord and ask in #custom-resource-packs for help, that channel contains a lot of information regarding custom items on Geyser and bedrock.