x402 Universal Payer

io.github.nirholas/x402-bridge·v1.0.0·Other

Pay any x402 endpoint on the open web: auto-paying bridge with Bazaar discovery and spend caps.

Trust verdict · v1 advisory · method

NOT YET SCREENEDno verdict on file

Verdict not yet evaluated for this tool. The semantic screen takes adversarial cases first; coverage rolls out as the corpus expands (15/150 labels to graduation). The deterministic conformance probe is built but has not yet run on the public corpus, so a recorded verdict here is REVIEW or UNVERIFIED, never a clearing ALLOW. Until a verdict is recorded, an agent should treat this tool as not-yet-cleared and fall back to its own checks. Method: the eval, four-state verdict, honest limits.

Own this server? Screen its description →

Environment variables

MCP_BRIDGE_EVM_PRIVATE_KEY

secret

0x-prefixed 32-byte hex private key that funds USDC payments on EVM chains (Base, Arbitrum, …). At least one of the EVM/SVM keys is required. Treat like cash — use a dedicated low-balance wallet.

MCP_BRIDGE_SVM_PRIVATE_KEY

secret

Solana secret key that funds USDC payments: base58 64-byte secret key (Phantom / solana-keygen format) or a JSON array of 64 integers. At least one of the EVM/SVM keys is required. Treat like cash.

MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC

Per-call spending cap in atomic units (USDC has 6 decimals). Payments above this abort with a clear reason.

MCP_BRIDGE_MAX_TOTAL_ATOMIC

Cumulative session spending ceiling in atomic units. Once total spend would exceed it, further payments abort until restart.

MCP_BRIDGE_ALLOWED_PAYTO

Comma-separated payee allowlist. When set, any payment whose payTo address is not listed is refused.

MCP_BRIDGE_ALLOWED_HOSTS

Comma-separated hostname allowlist for outbound paid requests. When set, any other host is refused before a request is signed.

MCP_BRIDGE_ALLOW_HTTP

Set to 1 to allow http:// targets (local development only). https is enforced otherwise.

MCP_BRIDGE_DISCOVER_LIMIT

Max number of x402 Bazaar resources to register as dynamic tools at startup. Set 0 to disable discovery.

MCP_BRIDGE_BAZAAR_URL

x402 Bazaar discovery endpoint. Override to point at a self-hosted or alternative bazaar.

MCP_BRIDGE_BATCH_DEPOSIT_MULTIPLIER

How many request-amounts to deposit at once when opening an EVM batch-settlement channel.

MCP_BRIDGE_MAX_DEPOSIT_ATOMIC

Hard cap in atomic units on a single batch-settlement channel deposit or top-up.

X402_MCP_BRIDGE_CHANNELS_DIR

Directory for persisted batch-settlement channel state (survives client restarts).

RPC_URL_8453

Per-chain RPC override, one variable per chain id (RPC_URL_<chainId>, e.g. RPC_URL_8453 for Base). Defaults to viem's public RPC for that chain.

MCP quality score · maturity, not trust · methodology

freshness

completeness

installability

documentation

stability

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Install

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "x402-bridge": {
      "command": "npx",
      "args": [
        "-y",
        "@three-ws/mcp-bridge"
      ],
      "env": {
        "MCP_BRIDGE_EVM_PRIVATE_KEY": "<your-mcp_bridge_evm_private_key>",
        "MCP_BRIDGE_SVM_PRIVATE_KEY": "<your-mcp_bridge_svm_private_key>",
        "MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC": "100000",
        "MCP_BRIDGE_MAX_TOTAL_ATOMIC": "1000000",
        "MCP_BRIDGE_ALLOWED_PAYTO": "<mcp_bridge_allowed_payto>",
        "MCP_BRIDGE_ALLOWED_HOSTS": "<mcp_bridge_allowed_hosts>",
        "MCP_BRIDGE_ALLOW_HTTP": "0",
        "MCP_BRIDGE_DISCOVER_LIMIT": "20",
        "MCP_BRIDGE_BAZAAR_URL": "https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources",
        "MCP_BRIDGE_BATCH_DEPOSIT_MULTIPLIER": "5",
        "MCP_BRIDGE_MAX_DEPOSIT_ATOMIC": "5000000",
        "X402_MCP_BRIDGE_CHANNELS_DIR": "~/.x402-mcp-bridge/channels",
        "RPC_URL_8453": "<rpc_url_8453>"
      }
    }
  }
}

Cursor (.cursor/mcp.json)

{
  "mcpServers": {
    "x402-bridge": {
      "command": "npx",
      "args": [
        "-y",
        "@three-ws/mcp-bridge"
      ],
      "env": {
        "MCP_BRIDGE_EVM_PRIVATE_KEY": "<your-mcp_bridge_evm_private_key>",
        "MCP_BRIDGE_SVM_PRIVATE_KEY": "<your-mcp_bridge_svm_private_key>",
        "MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC": "100000",
        "MCP_BRIDGE_MAX_TOTAL_ATOMIC": "1000000",
        "MCP_BRIDGE_ALLOWED_PAYTO": "<mcp_bridge_allowed_payto>",
        "MCP_BRIDGE_ALLOWED_HOSTS": "<mcp_bridge_allowed_hosts>",
        "MCP_BRIDGE_ALLOW_HTTP": "0",
        "MCP_BRIDGE_DISCOVER_LIMIT": "20",
        "MCP_BRIDGE_BAZAAR_URL": "https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources",
        "MCP_BRIDGE_BATCH_DEPOSIT_MULTIPLIER": "5",
        "MCP_BRIDGE_MAX_DEPOSIT_ATOMIC": "5000000",
        "X402_MCP_BRIDGE_CHANNELS_DIR": "~/.x402-mcp-bridge/channels",
        "RPC_URL_8453": "<rpc_url_8453>"
      }
    }
  }
}

Cline (cline_mcp_settings.json)

npx -y @three-ws/mcp-bridge

Verdict API

curl -s mcpindex.ai/api/v1/trust/server/io-github-nirholas-x402-bridge

Free-tier verdict as JSON: decision + dimensions + severity. Call it from your agent before it invokes a tool it just discovered.

Details

version: v1.0.0
category: Other
quality: 100 / 100
operator: nirholas

Provenance

Verdict history is anchored to Bitcoin via OpenTimestamps. The free tier returns the current verdict only; the anchored record is served on the authenticated tier.

Links

Repository →Website →