x402 Universal Payer

io.github.nirholas/x402-bridgev1.0.2Other

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

The current version, v1.0.2, was published to the official MCP registry on 2026-08-19. It is distributed as @three-ws/mcp-bridge on npm, filed under Other by this index, and declares 13 environment variables. Removals and unreachable sources are measured across every server this index tracks, contract drift across the servers that answer in consecutive snapshots; the index's current counts put this record in context.

In-path gate · all MCP tools

Using x402 Universal Payer in Claude, Cursor, Gemini CLI, Cline, or Zed?

MCP tool contracts can change remotely with no version bump. The mcpindex gate pins each contract and HOLDs the call when it drifts-before your agent acts. Zero credentials. This is not the package install for this server itself (use Install this server for that).

Install the mcpindex gate (one command)

Rewrites your MCP host config so each server launches behind the gate. Inspect first: curl -fsSL https://mcpindex.ai/install.sh | less

uv tool install mcpindex-gate && mcpindex-config-wire

Auditable install path →Watch it hold a drift →

Trust verdict · v1 advisory · method

REVIEWstatus: PARTIALfresh until 2026-09-18 14:37 UTC

screened 2026-07-22tier: scannedgranularity: description-levelsource: registry

Semantic screen found no manipulation pattern in the description. Conformance probe not yet run.

mcpindex.integrity.descriptionpassINFO

evidence“No malicious intent described”via static_description

Limits of this verdict

- Semantic screen only - the deterministic conformance probe has not run on this server
- Confidence is reported but not yet calibrated (v1)
- Screen reads the tool description, not the live behavior
- advisory
- registry description only no input schema
- screen model 8b
- Still current: the description we screened is unchanged, re-checked against the registry
- The registry listing (version, packages, links) changed after this screen ran - the description we assessed did not

Semantic screen: an LLM judge reads the tool description for hidden instructions (status PARTIAL). A pass means the description is not lying, not that the tool is safe: a high-capability tool with an honest description still warrants caution. The deterministic conformance probe has not been run on this server yet, so the screen here is semantic-only. Posture: advisory. Confidences are reported but not yet calibrated (calibrated=false at v1). Full verdict history is not shown on this page.

Own this server? Screen its description →

That verdict was true at screening time (snapshot 2026-09-11).

Contracts can change after screening, with no version bump. The gate pins x402 Universal Payer’s tool contracts on first sight and holds any silent change before your agent acts - the check that keeps being true on Tuesday.

See your first HOLD in 2 minutes →

Cite this record

People vet a server before wiring it in. One line on your project site or docs answers that with an independent record: screening verdict, registry provenance, contract drift history. It stays current as new screens and drift events land.

Markdown

[Independent trust record for x402 Universal Payer](https://mcpindex.ai/server/io-github-nirholas-x402-bridge) - screening verdict, registry provenance, and contract drift monitoring.

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<a href="https://mcpindex.ai/server/io-github-nirholas-x402-bridge">Independent trust record for x402 Universal Payer</a> - screening verdict, registry provenance, and contract drift monitoring.

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A live verdict badge for your README or listing. It reflects the current screen, links back here, and updates when the verdict does.

Markdown

[![mcpindex](https://mcpindex.ai/api/v1/badge/io-github-nirholas-x402-bridge)](https://mcpindex.ai/server/io-github-nirholas-x402-bridge)

HTML

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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

Alternatives in Other

AgentRoam

ai.agentroam/agentroam

Buy travel eSIMs, gift cards and mobile top-ups with crypto — user confirms before any order.

Authoryze

ai.authoryze/authoryze

Give your AI agent a spending limit: approval controls and single-use virtual cards.

x402 Wallet

io.github.nirholas/x402-mcp

Self-custodial x402 wallet for AI agents: pay any service in USDC or $THREE from your own key.

Install this server

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

Claude Code (claude mcp add)

claude mcp add --scope user x402-bridge -- npx -y -- @three-ws/mcp-bridge

Gemini CLI (gemini mcp add)

gemini mcp add -s user x402-bridge 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: v1.0.2
category: Other
verdict expires: 2026-09-18
quality: 100 / 100
operator: nirholas

Listing

Listed from the official MCP registry. Unclaimed by its maintainer. Maintainer? Email us →

Provenance

Each verdict is bound to a hash of the exact description it judged, so a re-crawl that changes the text produces a new record rather than silently inheriting this one. Verdict history is hash-chained and anchored to Bitcoin via OpenTimestamps (latest confirmed at block 966,455). Verify it yourself.

Links

Repository →Website →