ClawPay-mcp
Non-custodial x402 MCP payment layer for AI agents ā the open-source alternative to Vercel x402-mcp
README
ClawPay MCP
MCP server that gives any AI agent autonomous, spend-limited crypto payments via the Agent Wallet SDK on Base network.
What is ClawPay MCP?
ClawPay MCP is a Model Context Protocol server that wraps the Agent Wallet SDK (agentwallet-sdk) ā enabling any MCP-compatible AI client (Claude Desktop, Cursor, Windsurf, etc.) to make on-chain payments with built-in spend limit enforcement.
Key properties:
- š Non-custodial ā You hold your keys. The wallet is a smart contract you own via NFT.
- šø Spend-limited ā On-chain limits cap what agents can spend per-tx and per-period. Over-limit transactions queue for your approval.
- ā” x402-native ā Automatic HTTP 402 payment handling (pay-per-API-call, pay-per-token, etc.)
- š Base network ā Fast, cheap, EVM-compatible (Mainnet + Sepolia testnet)
Quick Start
1. Install
npm install -g clawpay-mcp
```text
### 2. Configure environment
Create a `.env` file (or set env vars for your MCP client):
```bash
# Required
AGENT_PRIVATE_KEY=0x... # Agent hot wallet private key
AGENT_WALLET_ADDRESS=0x... # Your deployed AgentAccountV2 address
# Optional (defaults shown)
CHAIN_ID=8453 # 8453 = Base Mainnet, 84532 = Base Sepolia
RPC_URL=https://mainnet.base.org
```text
> **Security note:** `AGENT_PRIVATE_KEY` is the agent's *hot wallet* signing key ā not the owner key. On-chain spend limits protect your funds. Even if the key is compromised, the agent can only spend within your configured limits.
### 3. Add to Claude Desktop
Edit `~/Library/Application Support/Claude/claude_desktop_config.json`:
```json
{
"mcpServers": {
"clawpay": {
"command": "clawpay-mcp",
"env": {
"AGENT_PRIVATE_KEY": "0x...",
"AGENT_WALLET_ADDRESS": "0x...",
"CHAIN_ID": "8453"
}
}
}
}
```text
Then restart Claude Desktop. You'll see the š§ ClawPay tools available in your conversation.
See [`claude_desktop_config.json`](claude_desktop_config.json) for a ready-to-copy template.
---
## Tools Reference
### 1. `deploy_wallet`
Deploy a new AgentAccountV2 wallet via the factory contract.
**Input:**
```json
{
"token_id": "1",
"factory_address": "0x...",
"nft_contract_address": "0x..."
}
```text
**Output:**
```text
ā
Agent Wallet deployed successfully!
š Wallet Address: 0xabc...
š Explorer: https://basescan.org/address/0xabc...
š Transaction: 0xdef...
š Owner NFT: 0xnft... #1
š Chain: Base Mainnet
ā¹ļø Next steps:
1. Set AGENT_WALLET_ADDRESS=0xabc... in your .env
2. Use set_spend_policy to configure spending limits
3. Fund the wallet with ETH or USDC
```text
---
### 2. `get_wallet_info`
Get wallet address, balance, spend limits, and remaining allowance.
**Input:**
```json
{
"token": "0x0000000000000000000000000000000000000000"
}
```text
*`token` is optional ā omit for native ETH.*
**Output:**
```text
š Agent Wallet Info
š Address: 0xabc...
š Chain: Base Mainnet
š° ETH Balance: 0.5 ETH
š Spend Limits (ETH)
Per-tx limit: 0.01 ETH
Period limit: 0.1 ETH
Period spent: 0.03 ETH
Remaining: 0.07 ETH
Utilization: 30% š¢ Healthy
Period length: 24h
Resets in: 18h 22m
```text
---
### 3. `send_payment`
Send ETH or ERC20 tokens within spend limits.
**Input:**
```json
{
"to": "0xrecipient...",
"amount_eth": "0.001",
"memo": "Payment for API access"
}
```text
For ERC20 (e.g. USDC):
```json
{
"to": "0xrecipient...",
"amount_eth": "5.00",
"token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"token_decimals": 6
}
```text
**Output:**
```text
ā
Payment Sent
To: 0xrecipient...
Amount: 0.001 ETH
Network: Base Mainnet
TX Hash: 0xabc...
š https://basescan.org/tx/0xabc...
š Memo: Payment for API access
```text
> If the payment exceeds spend limits, it's automatically queued for your approval. Use `queue_approval` to manage the queue.
---
### 4. `check_spend_limit`
Check if a proposed payment is within autonomous limits before sending.
**Input:**
```json
{
"amount_eth": "0.005"
}
```text
**Output:**
```text
š Spend Limit Check
Token: ETH
Amount: 0.005 ETH
Per-tx limit: 0.01 ETH
Within per-tx: ā
Yes
Remaining period: 0.07 ETH
Within period: ā
Yes
Resets in: 18h 22m
ā
APPROVED ā This payment can execute autonomously.
```text
---
### 5. `queue_approval`
Manage over-limit transactions queued for owner review.
**List pending:**
```json
{ "action": "list" }
```text
**Approve:**
```json
{ "action": "approve", "tx_id": "0" }
```text
**Cancel:**
```json
{ "action": "cancel", "tx_id": "0" }
```text
**Output (list):**
```text
š Pending Approvals (1 transaction)
āāāāāāāāāāāāāāāāāāāāāāāāā
Queue ID: 0
To: 0xrecipient...
Value: 0.05 ETH
Queued at: 2026-02-19T14:00:00.000Z
Use action="approve" with tx_id to approve, or action="cancel" to cancel.
```text
---
### 6. `x402_pay`
Fetch a URL and automatically handle HTTP 402 Payment Required responses.
**Input:**
```json
{
"url": "https://api.example.com/premium-data",
"max_payment_eth": "0.001",
"timeout_ms": 15000
}
```text
**Output:**
```text
š x402 Fetch Result
URL: https://api.example.com/premium-data
Status: 200 OK
Network: Base Mainnet
š³ Payment Made
Amount: 1000000 (base units)
Recipient: 0xpayee...
TX Hash: 0xpaymenttx...
š Response Body
{"access": "granted", "data": "...premium content..."}
```text
---
### 7. `get_transaction_history`
Retrieve on-chain transaction history from event logs.
**Input:**
```json
{
"limit": 10,
"event_type": "execution"
}
```text
**Output:**
```text
š Transaction History (2 entries)
Chain: Base Mainnet
Block range: 4000 ā latest
Filter: execution
ā” Transaction Executed
Block: 4523
TX: 0xabc...
š https://basescan.org/tx/0xabc...
To: 0xrecipient...
Value: 0.001 ETH
By: 0xagent...
```text
---
## Security Model
### Non-Custodial Architecture
ClawPay MCP wraps **AgentAccountV2** ā a smart contract wallet that you own via an NFT. The security model:
1. **You own the NFT** ā You own the wallet. If you transfer the NFT, the new holder controls the wallet.
2. **Agent hot key** ā `AGENT_PRIVATE_KEY` is a *limited* operator key. It can execute transactions only within the on-chain spend limits you set.
3. **On-chain spend limits** ā Set via `setSpendPolicy`. Caps per-transaction and per-period spending. Even if the agent key is compromised, the attacker is limited to your configured spend limits.
4. **Approval queue** ā Over-limit transactions are queued on-chain for your explicit approval. The agent cannot bypass this.
### Threat Model
| Threat | Mitigation |
|--------|------------|
| Compromised agent private key | On-chain spend limits cap exposure |
| Runaway agent (infinite payment loop) | Period limits + queue-on-exceed |
| x402 price manipulation | `max_payment_eth` cap parameter |
| Over-spending a single service | x402 per-service budget controls |
| Lost private key | Owner (NFT holder) remains in control |
---
## Configuration
| Variable | Required | Default | Description |
|----------|----------|---------|-------------|
| `AGENT_PRIVATE_KEY` | ā
| ā | Agent hot wallet private key (0x-prefixed hex) |
| `AGENT_WALLET_ADDRESS` | ā
| ā | Deployed AgentAccountV2 contract address |
| `CHAIN_ID` | ⬠| `8453` | Chain ID (8453 = Base Mainnet, 84532 = Base Sepolia) |
| `RPC_URL` | ⬠| Public Base RPC | Custom RPC endpoint (recommended for production) |
| `FACTORY_ADDRESS` | ⬠| ā | Required for `deploy_wallet` only |
| `NFT_CONTRACT_ADDRESS` | ⬠| ā | Required for `deploy_wallet` only |
> **Minimum to get started:** Just `AGENT_PRIVATE_KEY` + `AGENT_WALLET_ADDRESS`. Everything else has sensible defaults.
---
## Integration Examples
### Cursor / Windsurf
Add to your MCP settings:
```json
{
"mcpServers": {
"clawpay": {
"command": "npx",
"args": ["-y", "clawpay-mcp"],
"env": {
"AGENT_PRIVATE_KEY": "0x...",
"AGENT_WALLET_ADDRESS": "0x...",
"CHAIN_ID": "8453"
}
}
}
}
```text
### Using with a `.env` file
```bash
# Start with env file
AGENT_PRIVATE_KEY=$(cat ~/.clawpay/key) \
AGENT_WALLET_ADDRESS=0x... \
clawpay-mcp
```text
---
## Links
- **Agent Wallet SDK:** [agentwallet-sdk on npm](https://www.npmjs.com/package/agentwallet-sdk)
- **x402 Protocol:** [x402.org](https://x402.org)
- **Base Network:** [base.org](https://base.org)
- **MCP Spec:** [modelcontextprotocol.io](https://modelcontextprotocol.io)
---
## License
MIT ā see [LICENSE](LICENSE)
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