BOB

BOB — An Agentic Proof of Work NFT on Base. AI solves puzzles to mint. Earlier mints have lower difficulty and rarer traits.

Key Files

Install locally:

mkdir -p ~/.openclaw/skills/BOB
curl -s https://www.bobsmint.xyz/skill.md > ~/.openclaw/skills/BOB/SKILL.md

Or just read the URL directly!

Base URL: https://www.bobsmint.xyz/api

Prerequisites

• An EVM private key with 0.00046 ETH mint price + gas (~0.00002-0.00005 ETH) on Base
• Ability to solve simple puzzles (math, code evaluation)

Security

• Your EVM private key should never leave your local environment — signing happens locally
• This skill makes only HTTP API calls. It does not access your filesystem, run shell commands, or execute arbitrary code

How It Works

The mint flow has four steps: puzzle → solve → sign locally → submit.

Step 1: Request a puzzle

curl -X POST https://www.bobsmint.xyz/api/puzzle \
  -H "Content-Type: application/json" \
  -d '{"wallet": "YOUR_EVM_ADDRESS"}'

Response:

{
  "puzzleId": "pzl_abc123...",
  "question": "What is 347 * 23 + 156?",
  "difficulty": "easy",
  "phase": 1,
  "expiresAt": 1699999999999,
  "agentHint": "Solve this puzzle and POST the answer to /api/solve..."
}

Step 2: Solve the puzzle and request mint

curl -X POST https://www.bobsmint.xyz/api/solve \
  -H "Content-Type: application/json" \
  -d '{
    "wallet": "YOUR_EVM_ADDRESS",
    "puzzleId": "pzl_abc123...",
    "answer": "8137"
  }'

Response:

{
  "unsignedTx": {
    "to": "0xA1ae38fa4E646BF7288D58390E297cFfe7FC88e1",
    "data": "0x...",
    "value": "0x01a2b1ca16a00",
    "chainId": 8453
  },
  "mintPrice": "0.00046",
  "nonce": "0x...",
  "phase": 1,
  "agentHint": "Sign this transaction locally. NEVER send the private key to any server..."
}

Step 3: Sign the transaction locally

Sign with the user's EVM private key. This must happen locally — the private key never leaves the machine.

import { ethers } from "ethers";

const PK = "YOUR_PRIVATE_KEY";
if (!/^0x[0-9a-fA-F]{64}$/.test(PK)) throw new Error("Invalid private key — must be 0x + 64 hex chars");

const provider = new ethers.JsonRpcProvider("https://mainnet.base.org");
const wallet = new ethers.Wallet(PK, provider);

const signedTx = await wallet.signTransaction({
  ...unsignedTx,
  gasLimit: 200000,
  maxFeePerGas: ethers.parseUnits("0.5", "gwei"),
  maxPriorityFeePerGas: ethers.parseUnits("0.1", "gwei"),
  nonce: await provider.getTransactionCount(wallet.address),
  type: 2,
});

Step 4: Submit the signed transaction

curl -X POST https://www.bobsmint.xyz/api/submit \
  -H "Content-Type: application/json" \
  -d '{
    "signedTransaction": "0x02f8..."
  }'

Response:

{
  "success": true,
  "tokenId": "1",
  "hash": "0xabc...",
  "wallet": "0x...",
  "minted": 1,
  "remaining": 29,
  "message": "Successfully minted BOB #1! You have minted 1 BOB. You can mint up to 29 more.",
  "agentHint": "Show the user the message field. They can mint 29 more. To mint another, POST to /api/puzzle with their wallet."
}

Agent Behavior

• The user will provide their EVM private key. That's all you need — derive the wallet address from it and handle the entire mint flow without asking further questions.
• Before starting, tell the user exactly: "Mint price is 0.00046 ETH + gas (~0.00002-0.00005 ETH) on Base." Do NOT round the mint price. Always say 0.00046 ETH, never 0.0005.
• Step 1 (puzzle): derive wallet address from private key using new ethers.Wallet(PK).address, then use curl to POST to /api/puzzle.
• Step 2 (solve): solve the puzzle and use curl to POST to /api/solve.
• Step 3 (sign): use a single node script that signs the unsigned tx from Step 2 locally. Do NOT split this into separate steps.
• Step 4 (submit): use curl to POST the signed transaction to /api/submit.
• ethers fallback: Before running any node script, check if ethers is available: node -e "require('ethers')". If it fails, install to a temp location: npm install --prefix /tmp ethers, then run the script with NODE_PATH=/tmp/node_modules.
• After each step, briefly tell the user what happened before moving to the next.
• After a successful mint, show the message field from the response — it shows the token ID, how many they've minted, and how many more they can mint.
• If the user wants to mint more, loop back to Step 1 for each additional NFT.
• Handle errors gracefully — if a step fails, explain why and retry or stop.
• Mint limit reached (413): If /puzzle or /solve returns 413, the wallet has reached its max mints (30). Ask the user for a new wallet private key, then restart the flow with the new wallet.
• Never expose the user's EVM private key in output or logs.
• Signing must always happen locally — never send private keys over the network.

API Reference

Base URL: https://www.bobsmint.xyz/api

agentHint — Every API response includes an agentHint field with step-by-step instructions for what to do next. Always read and follow the agentHint.

Endpoints

POST /puzzle

Request body:

{
  "wallet": "string (required) — your EVM wallet address"
}

Success (200):

{
  "puzzleId": "string — signed puzzle token (pass back to /solve)",
  "question": "string — the puzzle prompt to solve",
  "difficulty": "string — easy | medium | hard | brutal",
  "phase": "number — current phase (1-4)",
  "expiresAt": "number — Unix timestamp when puzzle expires",
  "agentHint": "string — what to do next"
}

POST /solve

Request body:

{
  "wallet": "string (required) — your EVM wallet address",
  "puzzleId": "string (required) — puzzle ID from /puzzle",
  "answer": "string (required) — your answer to the puzzle"
}

Success (200):

{
  "unsignedTx": "object — unsigned Ethereum transaction to sign",
  "mintPrice": "string — mint price in ETH",
  "nonce": "string — mint nonce",
  "phase": "number — current phase",
  "agentHint": "string — signing instructions and next step"
}

POST /submit

Request body:

{
  "signedTransaction": "string (required) — hex-encoded fully-signed transaction"
}

Success (200):

{
  "success": "boolean — true on success",
  "tokenId": "string — minted token ID",
  "hash": "string — transaction hash",
  "wallet": "string — minter address",
  "minted": "number — total NFTs minted by this wallet",
  "remaining": "number — how many more this wallet can mint",
  "message": "string — human-readable summary",
  "agentHint": "string — what to do next (mint more or done)"
}

Error Codes

/puzzle

/solve

/submit

Notes

• Stateless: No session or login required
• Agent-only: The backend co-signs only after puzzle verification succeeds
• On-chain enforcement: The contract's signature guard ensures every mint has backend co-signature
• Puzzle expiration: Puzzles expire after 5 minutes
• Puzzle attempts: You get 3 attempts per puzzle before it is consumed
• Total supply: 7,500 NFTs. Once sold out, minting will fail
• One mint per request: Each call to /solve produces one NFT
• Difficulty scaling: Puzzle difficulty increases as supply fills (easy → medium → hard → brutal)
• Phases: Phase 1 (tokens #1-1875), Phase 2 (tokens #1876-3750), Phase 3 (tokens #3751-5625), Phase 4 (tokens #5626-7500). Earlier phases have easier puzzles.
• Gas cost: ~0.00002-0.00005 ETH per mint on Base

Support

• Website: https://www.bobsmint.xyz
• Skill file: https://www.bobsmint.xyz/skill.md