@b20labs/mcp — b20-operator

An MCP server that lets any AI assistant (Claude, Cursor, ChatGPT, …) inspect and simulate B20 — Base's native token standard — in natural language. Read + simulate only: it never signs a transaction or moves funds.

Powered by @b20labs/sdk — the same golden-vector-tested encoders.

Tools

| Tool | What it does | |---|---| | derive_b20_address | Zero-RPC: the address a B20 will get from (variant, deployer, salt) | | identify_b20 | Zero-RPC: is an address a B20, and which variant | | inspect_b20 | On-chain: name, symbol, decimals, supply, variant | | check_activation | Is a variant activated on Base (the only correct write-gate) | | simulate_create_b20 | Dry-run a deploy via eth_call → "would succeed" or the exact decoded revert (incl. failing initCall index). No signature, no gas. | | decode_b20_error | Turn raw revert bytes into a typed error + human message |

Use it

Add to your Claude Desktop / Cursor MCP config:

{
  "mcpServers": {
    "b20-operator": {
      "command": "npx",
      "args": ["-y", "@b20labs/mcp"],
      "env": { "B20_RPC": "https://mainnet.base.org" }
    }
  }
}

Then ask, e.g. "simulate deploying a rug-proof ASSET token called Doge Base, ticker DOGEB, 1B supply, from 0x… — will it work?"

Environment

| Var | Default | Purpose | |---|---|---| | B20_RPC (alias B20_RPC_URL) | https://mainnet.base.org | RPC endpoint for the on-chain tools. Use a managed Base RPC (Alchemy/QuickNode) — the public endpoint rate-limits under bursts. | | B20_CHAIN | base (mainnet, 8453) | Set to sepolia (84532) to point at Base Sepolia. Must match your B20_RPC network, or the client assumes mainnet. |

Notes

• simulate_create_b20 takes an optional salt (32-byte 0x…). Omit it and a random salt is used; the returned address is derived from that salt — reuse the same salt when you sign the real deploy, or the on-chain address will differ.
• STABLECOIN decimals are fixed at 6 and currency applies to STABLECOIN only — the simulator honors this and tells you when an input was ignored rather than silently dropping it.
• Every "write" is a read-only eth_call. The server never holds a key or broadcasts a transaction.

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