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Nft Standards

Seth HobsonCommunityCreated by Seth Hobson

  • Skill
  • Tool integration
  • Software development
  • MIT
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From the author

Implement NFT standards (ERC-721, ERC-1155) with proper metadata handling, minting strategies, and marketplace integration. Use when creating NFT contracts, building NFT marketplaces, or implementing digital asset systems.
— the description by Seth Hobson

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides technical patterns and code templates for developing non-fungible token systems on the Ethereum blockchain. It covers standard token implementations, metadata management strategies, and royalty configurations. The content includes examples for both off-chain and on-chain metadata, as well as specialized patterns like soulbound tokens, dynamic NFTs, and gas-optimized minting.

What it does

  • Provides Solidity templates for ERC-721 and ERC-1155 token standards.
  • Demonstrates methods for handling both IPFS-based and on-chain metadata.
  • Implements EIP-2981 for royalty distribution.
  • Includes patterns for soulbound (non-transferable) tokens.
  • Offers logic for dynamic NFTs that evolve based on state changes.
  • Shows gas-optimized minting approaches using external libraries.

When to use it

  • When developing NFT collections for art, gaming, or digital collectibles.
  • When building marketplace functionality requiring royalty support.
  • When implementing digital asset systems with specific transfer or state requirements.
  • When deciding between off-chain storage and on-chain metadata generation.

Advantages

  • Standardized code structures for common NFT use cases.
  • Clear separation between token logic and metadata handling.
  • Ready-to-use patterns for advanced features like royalties and soulbound status.
  • Provides both basic and optimized implementation examples.

Usage examples

“How do I implement a basic ERC-721 contract with a minting function?”
The skill provides a complete Solidity contract template using OpenZeppelin libraries, including minting logic, supply limits, and URI generation.
“Show me how to add royalty support to my NFT collection.”
The skill provides an example using the IERC2981 interface to define royalty recipients and fee percentages.
“How can I make an NFT that changes its metadata based on user actions?”
The skill provides a DynamicNFT pattern that uses a mapping to track token state and updates the tokenURI accordingly.
“What is the best way to store NFT metadata?”
The skill explains both off-chain storage via IPFS and on-chain generation using Base64 encoding and SVG generation.

Install

  1. Download the skill as a ZIP:

    https://mp-staging.autogineer.com/agent-skills/wshobson/nft-standards/download
  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip nft-standards.zip -d .agents/skills

Documentation by Seth Hobson

NFT Standards

Master ERC-721 and ERC-1155 NFT standards, metadata best practices, and advanced NFT features.

When to Use This Skill

  • Creating NFT collections (art, gaming, collectibles)

  • Implementing marketplace functionality

  • Building on-chain or off-chain metadata

  • Creating soulbound tokens (non-transferable)

  • Implementing royalties and revenue sharing

  • Developing dynamic/evolving NFTs

ERC-721 (Non-Fungible Token Standard)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Counters.sol";

contract MyNFT is ERC721URIStorage, ERC721Enumerable, Ownable {
    using Counters for Counters.Counter;
    Counters.Counter private _tokenIds;

    uint256 public constant MAX_SUPPLY = 10000;
    uint256 public constant MINT_PRICE = 0.08 ether;
    uint256 public constant MAX_PER_MINT = 20;

    constructor() ERC721("MyNFT", "MNFT") {}

    function mint(uint256 quantity) external payable {
        require(quantity > 0 && quantity <= MAX_PER_MINT, "Invalid quantity");
        require(_tokenIds.current() + quantity <= MAX_SUPPLY, "Exceeds max supply");
        require(msg.value >= MINT_PRICE * quantity, "Insufficient payment");

        for (uint256 i = 0; i < quantity; i++) {
            _tokenIds.increment();
            uint256 newTokenId = _tokenIds.current();
            _safeMint(msg.sender, newTokenId);
            _setTokenURI(newTokenId, generateTokenURI(newTokenId));
        }
    }

    function generateTokenURI(uint256 tokenId) internal pure returns (string memory) {
        // Return IPFS URI or on-chain metadata
        return string(abi.encodePacked("ipfs://QmHash/", Strings.toString(tokenId), ".json"));
    }

    // Required overrides
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId,
        uint256 batchSize
    ) internal override(ERC721, ERC721Enumerable) {
        super._beforeTokenTransfer(from, to, tokenId, batchSize);
    }

    function _burn(uint256 tokenId) internal override(ERC721, ERC721URIStorage) {
        super._burn(tokenId);
    }

    function tokenURI(uint256 tokenId) public view override(ERC721, ERC721URIStorage) returns (string memory) {
        return super.tokenURI(tokenId);
    }

    function supportsInterface(bytes4 interfaceId)
        public
        view
        override(ERC721, ERC721Enumerable)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }

    function withdraw() external onlyOwner {
        payable(owner()).transfer(address(this).balance);
    }
}

ERC-1155 (Multi-Token Standard)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract GameItems is ERC1155, Ownable {
    uint256 public constant SWORD = 1;
    uint256 public constant SHIELD = 2;
    uint256 public constant POTION = 3;

    mapping(uint256 => uint256) public tokenSupply;
    mapping(uint256 => uint256) public maxSupply;

    constructor() ERC1155("ipfs://QmBaseHash/{id}.json") {
        maxSupply[SWORD] = 1000;
        maxSupply[SHIELD] = 500;
        maxSupply[POTION] = 10000;
    }

    function mint(
        address to,
        uint256 id,
        uint256 amount
    ) external onlyOwner {
        require(tokenSupply[id] + amount <= maxSupply[id], "Exceeds max supply");

        _mint(to, id, amount, "");
        tokenSupply[id] += amount;
    }

    function mintBatch(
        address to,
        uint256[] memory ids,
        uint256[] memory amounts
    ) external onlyOwner {
        for (uint256 i = 0; i < ids.length; i++) {
            require(tokenSupply[ids[i]] + amounts[i] <= maxSupply[ids[i]], "Exceeds max supply");
            tokenSupply[ids[i]] += amounts[i];
        }

        _mintBatch(to, ids, amounts, "");
    }

    function burn(
        address from,
        uint256 id,
        uint256 amount
    ) external {
        require(from == msg.sender || isApprovedForAll(from, msg.sender), "Not authorized");
        _burn(from, id, amount);
        tokenSupply[id] -= amount;
    }
}

Metadata Standards

Off-Chain Metadata (IPFS)
{
  "name": "NFT #1",
  "description": "Description of the NFT",
  "image": "ipfs://QmImageHash",
  "attributes": [
    {
      "trait_type": "Background",
      "value": "Blue"
    },
    {
      "trait_type": "Rarity",
      "value": "Legendary"
    },
    {
      "trait_type": "Power",
      "value": 95,
      "display_type": "number",
      "max_value": 100
    }
  ]
}
On-Chain Metadata
contract OnChainNFT is ERC721 {
    struct Traits {
        uint8 background;
        uint8 body;
        uint8 head;
        uint8 rarity;
    }

    mapping(uint256 => Traits) public tokenTraits;

    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        Traits memory traits = tokenTraits[tokenId];

        string memory json = Base64.encode(
            bytes(
                string(
                    abi.encodePacked(
                        '{"name": "NFT #', Strings.toString(tokenId), '",',
                        '"description": "On-chain NFT",',
                        '"image": "data:image/svg+xml;base64,', generateSVG(traits), '",',
                        '"attributes": [',
                        '{"trait_type": "Background", "value": "', Strings.toString(traits.background), '"},',
                        '{"trait_type": "Rarity", "value": "', getRarityName(traits.rarity), '"}',
                        ']}'
                    )
                )
            )
        );

        return string(abi.encodePacked("data:application/json;base64,", json));
    }

    function generateSVG(Traits memory traits) internal pure returns (string memory) {
        // Generate SVG based on traits
        return "...";
    }
}

Royalties (EIP-2981)

import "@openzeppelin/contracts/interfaces/IERC2981.sol";

contract NFTWithRoyalties is ERC721, IERC2981 {
    address public royaltyRecipient;
    uint96 public royaltyFee = 500; // 5%

    constructor() ERC721("Royalty NFT", "RNFT") {
        royaltyRecipient = msg.sender;
    }

    function royaltyInfo(uint256 tokenId, uint256 salePrice)
        external
        view
        override
        returns (address receiver, uint256 royaltyAmount)
    {
        return (royaltyRecipient, (salePrice * royaltyFee) / 10000);
    }

    function setRoyalty(address recipient, uint96 fee) external onlyOwner {
        require(fee <= 1000, "Royalty fee too high"); // Max 10%
        royaltyRecipient = recipient;
        royaltyFee = fee;
    }

    function supportsInterface(bytes4 interfaceId)
        public
        view
        override(ERC721, IERC165)
        returns (bool)
    {
        return interfaceId == type(IERC2981).interfaceId ||
               super.supportsInterface(interfaceId);
    }
}

Additional patterns and templates

More detailed templates and worked examples live in references/details.md. Read that file for the full pattern library.

Files

references/details.md

nft-standards — additional patterns and templates

Soulbound Tokens (Non-Transferable)

contract SoulboundToken is ERC721 {
    constructor() ERC721("Soulbound", "SBT") {}

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId,
        uint256 batchSize
    ) internal virtual override {
        require(from == address(0) || to == address(0), "Token is soulbound");
        super._beforeTokenTransfer(from, to, tokenId, batchSize);
    }

    function mint(address to) external {
        uint256 tokenId = totalSupply() + 1;
        _safeMint(to, tokenId);
    }

    // Burn is allowed (user can destroy their SBT)
    function burn(uint256 tokenId) external {
        require(ownerOf(tokenId) == msg.sender, "Not token owner");
        _burn(tokenId);
    }
}

Dynamic NFTs

contract DynamicNFT is ERC721 {
    struct TokenState {
        uint256 level;
        uint256 experience;
        uint256 lastUpdated;
    }

    mapping(uint256 => TokenState) public tokenStates;

    function gainExperience(uint256 tokenId, uint256 exp) external {
        require(ownerOf(tokenId) == msg.sender, "Not token owner");

        TokenState storage state = tokenStates[tokenId];
        state.experience += exp;

        // Level up logic
        if (state.experience >= state.level * 100) {
            state.level++;
        }

        state.lastUpdated = block.timestamp;
    }

    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        TokenState memory state = tokenStates[tokenId];

        // Generate metadata based on current state
        return generateMetadata(tokenId, state);
    }

    function generateMetadata(uint256 tokenId, TokenState memory state)
        internal
        pure
        returns (string memory)
    {
        // Dynamic metadata generation
        return "";
    }
}

Gas-Optimized Minting (ERC721A)

import "erc721a/contracts/ERC721A.sol";

contract OptimizedNFT is ERC721A {
    uint256 public constant MAX_SUPPLY = 10000;
    uint256 public constant MINT_PRICE = 0.05 ether;

    constructor() ERC721A("Optimized NFT", "ONFT") {}

    function mint(uint256 quantity) external payable {
        require(_totalMinted() + quantity <= MAX_SUPPLY, "Exceeds max supply");
        require(msg.value >= MINT_PRICE * quantity, "Insufficient payment");

        _mint(msg.sender, quantity);
    }

    function _baseURI() internal pure override returns (string memory) {
        return "ipfs://QmBaseHash/";
    }
}

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Security

No issues found by our static scan· No issues found

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Created by
Seth Hobson
Publisher
Seth Hobson (Community)
Source
wshobson/agents · plugins/blockchain-web3/skills/nft-standards · commit 4bde316
Licence
MIT License (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

AutoGineer is not affiliated with or endorsed by Seth Hobson.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download nft-standards.zip