coti-private-nft

name	coti-private-nft
description	Deploys and manages privacy-preserving ERC721 NFTs on COTI blockchain. Use when user asks to 'deploy NFT', 'create private NFT', 'mint NFT', 'transfer NFT', 'ERC721', 'NFT collection', 'NFT balance', or 'check NFT owner'. Handles confidential NFT ownership and transfers.
metadata	{"author":"coti-io","version":"1.0.0","mcp-server":"coti-mcp","category":"blockchain","tags":["coti","privacy","erc721","nft","collectibles"]}

COTI Private NFTs (ERC721)

Overview

This skill deploys and manages privacy-preserving ERC721 NFTs on COTI. Private NFTs use garbled circuits to add confidentiality to ownership and transfer operations while maintaining full EVM compatibility.

Use cases include:

• Private collectibles — ownership visible only to authorized parties
• Confidential credentials — membership or access tokens without public disclosure
• Private proof-of-ownership — claim rights without revealing identity

Prerequisites

• The coti-mcp MCP server must be connected and running
• A COTI account with AES key must be configured (use coti-account-setup skill)
• Native COTI balance for gas fees

Workflow

Deploying an NFT Collection

1. Call deploy_private_erc721_contract with:
   • name: Collection name (e.g., "PrivateArt")
   • symbol: Collection symbol (e.g., "PART")
2. Save the returned contract address for all subsequent operations

Minting NFTs

1. Call mint_private_erc721_token with:
   • token_address: The deployed collection contract
   • to_address: Recipient wallet address
   • token_uri: Metadata URI (typically IPFS, e.g., "ipfs://Qm...")
2. Token IDs are auto-assigned sequentially starting from 0

Transferring NFTs

1. Call transfer_private_erc721 with:
   • token_address: The collection contract address
   • to_address: New owner wallet
   • token_id: The specific NFT to transfer (integer, not string)

Querying NFT Data

What you want	Tool	Key input
How many NFTs an address holds	get_private_erc721_balance	token_address, address
Who owns a specific token	get_private_erc721_token_owner	token_address, token_id
Metadata URI for a token	get_private_erc721_token_uri	token_address, token_id
Total minted supply	get_private_erc721_total_supply	token_address

Managing Approvals

What you want	Tool
Approve one token for transfer	approve_private_erc721
Approve operator for all tokens	set_private_erc721_approval_for_all
Check who is approved for a token	get_private_erc721_approved
Check if operator is approved for all	get_private_erc721_is_approved_for_all

Interaction Map

flowchart TD
    subgraph Deploy["Deploy Collection"]
        DC[deploy_private_erc721_contract\nname, symbol] -->|contractAddress| Addr[(collection address\nsave this!)]
    end

    subgraph Mint["Mint NFTs"]
        Addr --> MT[mint_private_erc721_token\ntoken_address, to_address, token_uri]
        MT -->|transactionHash\ntokenId auto-assigned| Minted([NFT minted])
    end

    subgraph Transfer["Transfer NFTs"]
        Addr --> TR[transfer_private_erc721\ntoken_address, to_address, token_id:int]
        TR -->|transactionHash| Transferred([ownership changed])
    end

    subgraph Query["Query NFT State"]
        Addr --> QB[get_private_erc721_balance\ntoken_address, address]
        Addr --> QO[get_private_erc721_token_owner\ntoken_address, token_id:int]
        Addr --> QU[get_private_erc721_token_uri\ntoken_address, token_id:int]
        Addr --> QS[get_private_erc721_total_supply\ntoken_address]
        QB -->|count or MPC note| Q1([balance])
        QO -->|address or MPC note| Q2([owner])
        QU -->|URI string| Q3([metadata URI])
        QS -->|total or MPC note| Q4([total supply])
    end

    subgraph Approvals["Approval Management"]
        Addr --> ASINGLE[approve_private_erc721\ntoken_address, to, token_id:int]
        Addr --> AALL[set_private_erc721_approval_for_all\ntoken_address, operator, approved:bool]
        Addr --> GSINGLE[get_private_erc721_approved\ntoken_address, token_id:int]
        Addr --> GALL[get_private_erc721_is_approved_for_all\ntoken_address, owner, operator]
    end

    subgraph CrossSkill["Cross-Skill"]
        ACCT["coti-account-setup\n(wallet + AES key)"] --> DC
        MT --> TX["coti-transaction-tools:\nget_transaction_status"]
        TR --> TX
    end

Data Flow

Tool	Key Inputs	Key Outputs	Notes
deploy_private_erc721_contract	name, symbol	contractAddress	Deployer becomes owner
mint_private_erc721_token	token_address, to_address, token_uri	transactionHash	token_id auto-assigned
transfer_private_erc721	token_address, to_address, token_id (int)	transactionHash	token_id must be integer
get_private_erc721_balance	token_address, address	count	MPC layer may return encrypted bytes
get_private_erc721_token_owner	token_address, token_id (int)	address	MPC layer may return encrypted bytes
get_private_erc721_token_uri	token_address, token_id (int)	URI string	Plain string, not encrypted
get_private_erc721_total_supply	token_address	count	MPC layer may return encrypted bytes
approve_private_erc721	token_address, to, token_id (int)	transactionHash	Single token approval
set_private_erc721_approval_for_all	token_address, operator, approved (bool)	transactionHash	Operator approval
get_private_erc721_approved	token_address, token_id (int)	address	—
get_private_erc721_is_approved_for_all	token_address, owner, operator	boolean	—

Tool Reference

deploy_private_erc721_contract

Deploys a new private ERC721 collection. Returns the contract address. The deployer becomes the owner and can mint tokens.

mint_private_erc721_token

Mints a new NFT to a specified address with a token URI. Token IDs are assigned automatically starting from 0.

transfer_private_erc721

Transfers an NFT to a new owner. The caller must be the current owner or an approved operator.

get_private_erc721_balance

Returns the number of NFTs held by an address. Due to garbled-circuit encryption, may return encrypted bytes — this is expected behavior.

get_private_erc721_token_owner

Returns the current owner address of a specific token ID.

get_private_erc721_token_uri

Returns the metadata URI associated with a token (e.g., "ipfs://Qm..."). This value is not encrypted.

get_private_erc721_total_supply

Returns the total number of minted tokens in the collection. garbled-circuit-encrypted on-chain — may return a decode note.

approve_private_erc721

Approves another address to transfer a specific token. Only the token owner can call this.

set_private_erc721_approval_for_all

Grants or revokes operator status for ALL of the caller's tokens in one call (standard ERC721 operator pattern).

get_private_erc721_approved

Returns the currently approved address for a specific token ID.

get_private_erc721_is_approved_for_all

Returns a boolean indicating whether an operator is approved for all tokens of a given owner.

Error Handling

• "not owner or approved": The caller is not the token owner and has not been approved to transfer it. Call approve_private_erc721 or set_private_erc721_approval_for_all first.
• "token does not exist": The token ID has not been minted. Check with get_private_erc721_total_supply to see the current count.
• "not authorized to mint": Only the contract owner (deployer) can mint. Verify you are using the same wallet that deployed the collection.
• "could not decode result data": Expected behavior for garbled-circuit encrypted state reads (balance, owner, totalSupply). Values are encrypted on-chain — the tool is working correctly.

Examples

Deploy a private NFT collection:

"Create a private NFT collection called SecretArt with symbol SART"

1. deploy_private_erc721_contract with name: "SecretArt", symbol: "SART"
2. Save the returned contract address

Mint an NFT:

"Mint an NFT to my wallet with metadata at ipfs://Qm..."

1. mint_private_erc721_token with token_address: "0x...", to_address: "0xMyWallet", token_uri: "ipfs://Qm..."
2. Returns transaction hash; token ID starts at 0

Check ownership:

"Who owns token number 3?"

1. get_private_erc721_token_owner with token_address: "0x...", token_id: 3

Transfer an NFT:

"Send token 2 to 0xRecipient"

1. transfer_private_erc721 with token_address: "0x...", to_address: "0xRecipient", token_id: 2

Important Notes

• token_id must be an integer (not a string). Pass 3 not "3".
• Parameter names use token_address (not contractAddress) and to_address (not to) — exact spelling matters for the MCP tool schema.
• Token URIs typically point to IPFS or other decentralized storage for metadata JSON.
• Approval patterns follow standard ERC721 conventions — use single-token approval for specific delegations, operator approval for full delegations (e.g., a marketplace).
• garbled-circuit encrypted state reads (balance, owner, totalSupply) may return encrypted bytes on the COTI testnet — this is expected, not an error.