b402-mcp

Model Context Protocol server for b402 payments and private DeFi.

Works with Claude Desktop, Cursor, Copilot, and other MCP-compatible clients.

5-line quickstart

export WORKER_PRIVATE_KEY=0xYOUR_BASE_KEY
export SEQUENCER_URL=https://your-sequencer-url
npx -y [email protected] --help
claude mcp add b402 --scope user -e WORKER_PRIVATE_KEY=$WORKER_PRIVATE_KEY -e SEQUENCER_URL=$SEQUENCER_URL -- npx -y [email protected]
# then ask Claude: "run b402_balance"

Claude Desktop / MCP config snippet

{
  "mcpServers": {
    "b402": {
      "command": "npx",
      "args": ["-y", "[email protected]"],
      "env": {
        "WORKER_PRIVATE_KEY": "0x...",
        "SEQUENCER_URL": "https://your-sequencer-url"
      }
    }
  }
}

Payment tools

| Tool | Description | |------|-------------| | b402_pay | Gasless b402 sequencer payment | | b402_balance | Sequencer credit or wallet/pool balance | | b402_create_invoice | Creates invoice payload + b402://pay URL | | pay_via_b402 | Standard HTTP 402 verify+settle flow with payment signature retry |

Private DeFi tools

| Tool | Description | |------|-------------| | shield_usdc | Move USDC into the Railgun privacy pool | | check_pool_balance | Show wallet + shielded balances and positions | | get_swap_quote | Read-only DEX quote across Base liquidity | | private_swap | Swap in privacy pool with ZK proof | | lend_privately | Lend from pool into Morpho vault | | redeem_privately | Redeem from Morpho vault back to pool | | run_strategy | Multi-step private strategy (swap + lend + reserve) |

Copy-paste E2E prompt

1) Run b402_balance with my agentId.
2) Create an invoice for 0.05 USDC with memo "demo call".
3) Run pay_via_b402 on my paid API URL.
4) Run b402_balance again and summarize the delta.

Network notes

• pay_via_b402 parses both Base and BNB x402 payment requirements.
• Automatic funding (fundIncognito) currently uses Base USDC only.
• Base private DeFi tools (shield_usdc, private_swap, lend_privately, etc.) remain Base-focused.

Environment

| Variable | Required | Description | |----------|----------|-------------| | WORKER_PRIVATE_KEY | Yes | Base wallet private key used by b402 | | SEQUENCER_URL | For b402_pay / credit tools | b402 sequencer endpoint | | BASE_RPC_URL | No | Custom Base RPC URL | | BNB_RPC_URL | No | Optional RPC used when x402 requirement is BNB | | FACILITATOR_URL | No | Custom b402 facilitator URL |

Links

• SDK: @b402ai/sdk
• Package: b402-mcp
• GitHub: b402ai/b402-sdk