# x402 Universal Payer An MCP server that settles x402 payments for your agent: it signs, retries and returns the response with a settlement receipt, under spending caps. - MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 249 - Author: nirholas - License: Apache-2.0 · policy=link-only · description only; the file stays with the author - Source: https://github.com/nirholas/three.ws/tree/HEAD/mcp-bridge - Updated: 2026-10-24 - HTML: https://affpapa.org/en/nevibecode/mcp/x402-universal-payer ## What it does Point your agent at a URL that answers `402 Payment Required`. The bridge signs the payment, retries the request and hands back the response plus a parsed settlement. EVM exact, EVM batch-settlement and Solana exact are all supported. Four tools ship with it. `call_paid_endpoint` is the fallback: any URL, auto-pay on 402. `list_bazaar_tools` returns the cached Bazaar list and `refresh_bazaar` re-queries the feed and re-registers tools without a restart — both free. On top of that you get one tool per discovered Bazaar resource, up to `MCP_BRIDGE_DISCOVER_LIMIT`. Anything priced above the per-call cap is dropped at discovery time. The server holds private keys and spends real USDC, so use a dedicated wallet with a small balance. At least one of `MCP_BRIDGE_EVM_PRIVATE_KEY` or `MCP_BRIDGE_SVM_PRIVATE_KEY` is required. `MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC` caps a single payment, `MCP_BRIDGE_MAX_TOTAL_ATOMIC` caps the whole session — once hit, further payments abort until restart. Payee and host allowlists are available, and outbound URLs are checked against private and loopback addresses. Retrying a paid call is a new charge. ## Requirements - Needs: Node.js (commands run via npx) - Environment variables: `MCP_BRIDGE_EVM_PRIVATE_KEY`, `MCP_BRIDGE_SVM_PRIVATE_KEY`, `MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC`, `MCP_BRIDGE_MAX_TOTAL_ATOMIC`, `MCP_BRIDGE_ALLOWED_PAYTO`, `MCP_BRIDGE_ALLOWED_HOSTS`, `MCP_BRIDGE_ALLOW_HTTP`, `MCP_BRIDGE_DISCOVER_LIMIT`, `MCP_BRIDGE_BAZAAR_URL`, `MCP_BRIDGE_BATCH_DEPOSIT_MULTIPLIER` — keys and tokens: ask the human for the values, never commit them or put them in shared files. ## Install ### Claude Code (native platform) **Platform CLI** ```bash claude mcp add --env MCP_BRIDGE_EVM_PRIVATE_KEY= --env MCP_BRIDGE_SVM_PRIVATE_KEY= --env MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC= --env MCP_BRIDGE_MAX_TOTAL_ATOMIC= --env MCP_BRIDGE_ALLOWED_PAYTO= --transport stdio mcp-bridge -- npx -y @three-ws/mcp-bridge ``` Replace <…> with your own values. 8 more environment variables are in the server README ### Codex **Platform CLI** ```bash codex mcp add mcp-bridge --env MCP_BRIDGE_EVM_PRIVATE_KEY= --env MCP_BRIDGE_SVM_PRIVATE_KEY= --env MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC= --env MCP_BRIDGE_MAX_TOTAL_ATOMIC= --env MCP_BRIDGE_ALLOWED_PAYTO= -- npx -y @three-ws/mcp-bridge ``` Replace <…> with your own values. 8 more environment variables are in the server README ### Cursor **Config file** File `.cursor/mcp.json`: ```json { "mcpServers": { "mcp-bridge": { "command": "npx", "args": [ "-y", "@three-ws/mcp-bridge" ], "env": { "MCP_BRIDGE_EVM_PRIVATE_KEY": "", "MCP_BRIDGE_SVM_PRIVATE_KEY": "", "MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC": "", "MCP_BRIDGE_MAX_TOTAL_ATOMIC": "", "MCP_BRIDGE_ALLOWED_PAYTO": "" } } } } ``` Replace <…> with your own values. 8 more environment variables are in the server README ### GitHub Copilot **Config file** File `.vscode/mcp.json`: ```json { "servers": { "mcp-bridge": { "type": "stdio", "command": "npx", "args": [ "-y", "@three-ws/mcp-bridge" ], "env": { "MCP_BRIDGE_EVM_PRIVATE_KEY": "", "MCP_BRIDGE_SVM_PRIVATE_KEY": "", "MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC": "", "MCP_BRIDGE_MAX_TOTAL_ATOMIC": "", "MCP_BRIDGE_ALLOWED_PAYTO": "" } } } } ``` Replace <…> with your own values. 8 more environment variables are in the server README ### Gemini CLI **Platform CLI** ```bash gemini mcp add -e MCP_BRIDGE_EVM_PRIVATE_KEY= -e MCP_BRIDGE_SVM_PRIVATE_KEY= -e MCP_BRIDGE_MAX_PRICE_PER_CALL_ATOMIC= -e MCP_BRIDGE_MAX_TOTAL_ATOMIC= -e MCP_BRIDGE_ALLOWED_PAYTO= mcp-bridge npx -y @three-ws/mcp-bridge ``` Replace <…> with your own values. 8 more environment variables are in the server README ## When to use it - pay a paid API from inside the agent without a manual invoice - get the response and settlement receipt from an x402 endpoint - cap agent spending per call and per session - expose x402 Bazaar services as ready-made tools - block payments to untrusted addresses and hosts ## Example prompts - Pay $0.01 on Base for a weather report and show me the receipt - Refresh the Bazaar tool list with `refresh_bazaar` - Call `call_paid_endpoint` on this URL and return the response ## Similar - [REA](https://affpapa.org/en/nevibecode/mcp/rea.md) — MCP server · ★ 386989 - [GitHub](https://affpapa.org/en/nevibecode/mcp/github.md) — MCP server · ★ 33918 - [Netdata](https://affpapa.org/en/nevibecode/mcp/netdata.md) — MCP server · ★ 81115 - [browser-use](https://affpapa.org/en/nevibecode/mcp/browser-use.md) — MCP server · ★ 119160 - [Codebase Memory](https://affpapa.org/en/nevibecode/mcp/codebase-memory.md) — MCP server · ★ 47392 - [mcp-server](https://affpapa.org/en/nevibecode/mcp/mcp-server.md) — MCP server · ★ 43872 From the same set: [nirholas/three.ws](https://affpapa.org/en/nevibecode/by/nirholas/three.ws.md) — 43 cards --- NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md