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name: dojo-token description: Implement ERC20 and ERC721 token standards in Dojo using Origami library. Use when adding fungible tokens, NFTs, or token-based game mechanics. allowed-tools: Read, Write, Edit, Glob, Grep

Dojo Token Standards

Implement ERC20 fungible tokens and ERC721 NFTs in your Dojo game using the Origami library.

When to Use This Skill

• "Implement ERC20 token for game currency"
• "Create NFT items with ERC721"
• "Add token standard to my game"
• "Use Origami for tokens"

What This Skill Does

Implements token standards:

• ERC20 fungible tokens (currency, resources)
• ERC721 non-fungible tokens (items, characters)
• Token minting and burning
• Transfer mechanics
• Balance tracking

Token Standards

ERC20 - Fungible Tokens

For interchangeable assets:

• Game currency (gold, gems)
• Resources (wood, stone)
• Experience points

Properties:

• Divisible (can have fractions)
• Interchangeable (any token = any other)
• Track balances per account

ERC721 - Non-Fungible Tokens

For unique assets:

• Character NFTs
• Equipment/items
• Land plots
• Achievements

Properties:

• Unique (each has token ID)
• Indivisible (whole units only)
• Individual ownership tracking

Using Origami Library

Installation

Add to Scarb.toml:

Copy[dependencies]
origami_token = { git = "https://github.com/dojoengine/origami", tag = "v1.0.0" }

Origami provides reusable token components following standard interfaces. Refer to the Origami documentation for the latest API.

Simple Token Implementation

You can implement tokens using standard Dojo models without Origami:

ERC20-like Currency

Copy#[derive(Copy, Drop, Serde)]
#[dojo::model]
pub struct Gold {
    #[key]
    pub player: ContractAddress,
    pub amount: u256,
}

#[starknet::interface]
trait IGoldToken<T> {
    fn mint(ref self: T, to: ContractAddress, amount: u256);
    fn transfer(ref self: T, to: ContractAddress, amount: u256);
    fn balance_of(self: @T, account: ContractAddress) -> u256;
}

#[dojo::contract]
mod gold_token {
    use super::{IGoldToken, Gold};
    use starknet::{ContractAddress, get_caller_address};
    use dojo::model::ModelStorage;

    #[abi(embed_v0)]
    impl GoldTokenImpl of IGoldToken<ContractState> {
        fn mint(ref self: ContractState, to: ContractAddress, amount: u256) {
            let mut world = self.world_default();

            let mut balance: Gold = world.read_model(to);
            balance.amount += amount;
            world.write_model(@balance);
        }

        fn transfer(ref self: ContractState, to: ContractAddress, amount: u256) {
            let mut world = self.world_default();
            let from = get_caller_address();

            let mut from_balance: Gold = world.read_model(from);
            let mut to_balance: Gold = world.read_model(to);

            assert(from_balance.amount >= amount, 'insufficient balance');

            from_balance.amount -= amount;
            to_balance.amount += amount;

            world.write_model(@from_balance);
            world.write_model(@to_balance);
        }

        fn balance_of(self: @ContractState, account: ContractAddress) -> u256 {
            let world = self.world_default();
            let balance: Gold = world.read_model(account);
            balance.amount
        }
    }

    #[generate_trait]
    impl InternalImpl of InternalTrait {
        fn world_default(self: @ContractState) -> dojo::world::WorldStorage {
            self.world(@"my_game")
        }
    }
}

ERC721-like NFT

Copy#[derive(Copy, Drop, Serde)]
#[dojo::model]
pub struct Weapon {
    #[key]
    pub token_id: u256,
    pub owner: ContractAddress,
    pub damage: u32,
    pub rarity: u8,
}

#[starknet::interface]
trait IWeaponNFT<T> {
    fn mint(ref self: T, to: ContractAddress, damage: u32) -> u256;
    fn transfer(ref self: T, to: ContractAddress, token_id: u256);
    fn owner_of(self: @T, token_id: u256) -> ContractAddress;
}

#[dojo::contract]
mod weapon_nft {
    use super::{IWeaponNFT, Weapon};
    use starknet::{ContractAddress, get_caller_address};
    use dojo::model::ModelStorage;

    #[abi(embed_v0)]
    impl WeaponNFTImpl of IWeaponNFT<ContractState> {
        fn mint(ref self: ContractState, to: ContractAddress, damage: u32) -> u256 {
            let mut world = self.world_default();

            let token_id: u256 = world.uuid().into();

            let weapon = Weapon {
                token_id,
                owner: to,
                damage,
                rarity: 1,
            };

            world.write_model(@weapon);
            token_id
        }

        fn transfer(ref self: ContractState, to: ContractAddress, token_id: u256) {
            let mut world = self.world_default();
            let from = get_caller_address();

            let mut weapon: Weapon = world.read_model(token_id);
            assert(weapon.owner == from, 'not owner');

            weapon.owner = to;
            world.write_model(@weapon);
        }

        fn owner_of(self: @ContractState, token_id: u256) -> ContractAddress {
            let world = self.world_default();
            let weapon: Weapon = world.read_model(token_id);
            weapon.owner
        }
    }

    #[generate_trait]
    impl InternalImpl of InternalTrait {
        fn world_default(self: @ContractState) -> dojo::world::WorldStorage {
            self.world(@"my_game")
        }
    }
}

Game Patterns

In-Game Currency

Copy// Award gold for completing quest
fn complete_quest(ref self: ContractState, quest_id: u32) {
    let mut world = self.world_default();
    let player = get_caller_address();

    // Check quest is completed
    // ...

    // Award gold
    let mut gold: Gold = world.read_model(player);
    gold.amount += 100;
    world.write_model(@gold);
}

// Spend gold to buy item
fn buy_item(ref self: ContractState, item_id: u32, price: u256) {
    let mut world = self.world_default();
    let player = get_caller_address();

    let mut gold: Gold = world.read_model(player);
    assert(gold.amount >= price, 'insufficient gold');

    gold.amount -= price;
    world.write_model(@gold);

    // Give item to player
    // ...
}

Multiple Resource Types

Copy#[derive(Copy, Drop, Serde)]
#[dojo::model]
pub struct Resources {
    #[key]
    pub player: ContractAddress,
    pub wood: u256,
    pub stone: u256,
    pub iron: u256,
}

Equipment NFTs

Copyfn equip_weapon(ref self: ContractState, token_id: u256) {
    let mut world = self.world_default();
    let player = get_caller_address();

    // Check ownership
    let weapon: Weapon = world.read_model(token_id);
    assert(weapon.owner == player, 'not owner');

    // Equip
    let mut equipment: Equipment = world.read_model(player);
    equipment.weapon_id = token_id;
    world.write_model(@equipment);
}

Token Events

Copy#[derive(Copy, Drop, Serde)]
#[dojo::event]
pub struct TokenTransferred {
    #[key]
    pub from: ContractAddress,
    #[key]
    pub to: ContractAddress,
    pub amount: u256,
}

#[derive(Copy, Drop, Serde)]
#[dojo::event]
pub struct NFTTransferred {
    #[key]
    pub token_id: u256,
    pub from: ContractAddress,
    pub to: ContractAddress,
}

// Emit in your functions
world.emit_event(@TokenTransferred { from, to, amount });

Considerations

• Balance checks: Always verify sufficient balance before transfers
• Ownership: Always verify ownership before NFT operations
• Overflow: Use u256 for token amounts to avoid overflow
• Events: Emit events for all token operations for indexing
• Permissions: Grant writer permission to token contracts

Next Steps

After implementing tokens:

1. Test thoroughly with dojo-test skill
2. Deploy with dojo-deploy skill
3. Integrate with client (dojo-client skill)
4. Set up permissions (dojo-world skill)

Related Skills

• dojo-model: Token models extend Dojo models
• dojo-system: Token logic in systems
• dojo-test: Test token operations
• dojo-review: Audit token implementation