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q402 MCP Setup & Guide

MCP ServerMCP RegistryOfficial

io.github.quackai-org/q402-mcp · v0.11.33

Q402 - gasless payments, yield, escrow, bridge & NAV triggers on 12 EVM chains. Sandbox-default.

Copy the install config on this page first, then verify docs and permissions upstream.

Overview

Q402 - gasless payments, yield, escrow, bridge & NAV triggers on 12 EVM chains. Sandbox-default. q402-mcp is a MCP Server listed from MCP Registry. Transports: stdio. This page includes an overview, setup tutorial, install commands, and use cases for Trae, Tongyi Lingma, Cursor, Claude Code, and VS Code.

Use cases

AgentHub Verified AvailabilityTested & Ready

Automated pipeline validated install commands, protocol & client compatibility

Verified At2026-10-31
Install Snippets TestedCLI & JSON config syntax verified
Protocol Handshake ReadyComplies with JSON-RPC 2.0 specifications
Origin Registry ActiveSourced from official-mcp-registry
Verified ClientsClaude Code、Claude Desktop、Cursor 等
Security Tier: A+ 级 · 官方认证推荐 (A+)·Maintained by official/verified teams, audited for standard MCP protocol compliance.

Copy by platform

Choose your platform

  1. Open or create .cursor/mcp.json in your project root
  2. Click Copy config and paste; merge only this mcpServers entry if others exist
  3. Replace <placeholders> in env with real secrets (see Environment variables below)
  4. Save, then Cmd+Shift+P → Reload Window

Pre-fill Environment Variables (Optional)

secret
secret
secret
secret
secret
Privacy Guarantee: Keys are replaced 100% locally in your browser memory and are NEVER uploaded or stored on any server.
Click to copy snippet
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

Setup tutorial

  1. Open the q402-mcp page and confirm this MCP Server (source: MCP Registry).
  2. Copy the Cursor, Claude Code, or VS Code snippet.
  3. Merge it into mcpServers and replace env placeholders with real secrets.
  4. Reload the window, then call the MCP tools from your agent chat.

Install commands

Install commands and setup steps are in the HTML so search engines and no-JS browsers can read them without running client JavaScript.

Claude Code (local)

  1. Install Claude Code CLI
  2. Copy the command below, replace <placeholders> with real env values, then run in terminal
  3. See Environment variables below if listed
claude mcp add q402-mcp -- npx -y @quackai/q402-mcp

Cursor — .cursor/mcp.json (local)

  1. Open or create .cursor/mcp.json in your project root
  2. Click Copy config and paste; merge only this mcpServers entry if others exist
  3. Replace <placeholders> in env with real secrets (see Environment variables below)
  4. Save, then Cmd+Shift+P → Reload Window
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

VS Code — .vscode/mcp.json (local)

  1. Install GitHub Copilot in VS Code with MCP support
  2. Open or create .vscode/mcp.json in your project root
  3. Click Copy config and paste; merge only this mcpServers entry if others exist
  4. Replace <placeholders> in env with real secrets
  5. Save and Developer: Reload Window
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

Claude Desktop — claude_desktop_config.json (local)

  1. Open Claude Desktop claude_desktop_config.json (see remote guide for paths)
  2. Click Copy config and merge under mcpServers
  3. Replace <placeholders> in env with real secrets
  4. Fully quit and restart Claude Desktop
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

Trae — .trae/mcp.json (local)

  1. Trae → Settings → MCP, or edit .trae/mcp.json / global mcp.json
  2. Click Copy config and merge mcpServers
  3. Replace <placeholders> in env with real secrets
  4. Save and reload Trae
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

Cherry Studio — MCP settings (local)

  1. Cherry Studio → Settings → MCP Servers → Add (STDIO)
  2. Or import JSON: click Copy config and merge mcpServers
  3. Replace <placeholders> in env; ensure Node.js / uv (npx, uvx) are installed
  4. Enable the server and check tools load
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

Tongyi Lingma — MCP config (local)

  1. Lingma Settings → MCP → + → STDIO or config file
  2. Click Copy config and merge mcpServers
  3. Replace <placeholders> in env; need Node.js 18+ (npx) or uv (uvx)
  4. Confirm connected before using tools in agent chat
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

Windsurf — mcp_config.json (local)

  1. Edit ~/.codeium/windsurf/mcp_config.json
  2. Click Copy config and merge mcpServers (stdio same as Cursor)
  3. Replace <placeholders> in env, save, refresh Cascade
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

Cline — MCP Servers (local)

  1. Cline panel → Settings → MCP Servers
  2. Click Copy config and merge
  3. Replace <placeholders> in env, then save
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

WorkBuddy — .workbuddy/mcp.json (local)

  1. Edit ~/.workbuddy/mcp.json (user) or project .workbuddy/mcp.json
  2. Or Plugins → MCP Servers → Configure MCP and paste the JSON below
  3. Replace <placeholders> in env; on Windows prefer absolute paths for command/scripts
  4. Save, restart WorkBuddy, confirm connector status is green
{
  "mcpServers": {
    "q402-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@quackai/q402-mcp"
      ]
    }
  }
}

Troubleshooting & Common ErrorsFAQ

Common connection errors and verified fixes for q402-mcp

Getting 'connection closed' or exit code 1 in Cursor / Claude Code for q402-mcp?

Usually caused by missing runtime paths or IDE environment inheritance. Fix steps: 1. Verify Node.js 18+ (npx) or Python 3.10+ (uvx) is installed; 2. Run 'which npx' or 'which uvx' in terminal, and replace 'command' with absolute path; 3. Reload or restart the client window after modifying config.

Fix Snippet
# Check binary path in terminal:
which npx
node -v
Getting 'spawn npx ENOENT' or 'command not found'?

The editor background process does not inherit your full terminal PATH. Solution: Globally install the package, or set the absolute binary path (e.g. C:\Program Files\nodejs\npx.cmd on Windows, or /usr/local/bin/npx on macOS).

Missing required environment variable or authentication failure?

q402-mcp requires environment variables (Q402_TRIAL_API_KEY、Q402_MULTICHAIN_API_KEY、Q402_PRIVATE_KEY、Q402_AGENTIC_PRIVATE_KEY、Q402_ENABLE_REAL_PAYMENTS、Q402_MAX_AMOUNT_PER_CALL、Q402_ALLOWED_RECIPIENTS、Q402_RELAY_BASE_URL、Q402_AGENT_WALLET_ADDRESS、Q402_API_KEY、Q402_WALLET_ID、Q402_BUILDER_CODE). Ensure you have added valid keys under the 'env' object in your config file without trailing whitespace.

Fix Snippet
// .cursor/mcp.json 或 claude_desktop_config.json
{
  "env": {
    "API_KEY": "your_actual_key_here"
  }
}

Tool Mock Playground

Sandbox

q402-mcp Tool Interface Simulation · Preview tool schema & outputs without local runtime

Sandbox Ready
fn: q402_mcpExecute the core tool interface of q402-mcp
Request ArgumentsJSON Schema
{
  "target": "q402-mcp",
  "action": "execute",
  "options": {
    "mode": "standard",
    "timeoutMs": 5000
  }
}
💡Parameters generated dynamically by Agent runtime
Agent Tool Output

Click 'Run Mock' above

to preview the raw response returned to the LLM

Env: AgentHub Virtual SandboxJSON-RPC 2.0

Decision Guide: Why & When to Use

Assess suitability before installing to save trial-and-error time

Best Suited For
  • PR review
  • Changelog generation
  • Cross-repo issue search
When NOT to Use
  • Replacing human security audit
  • Unauthorized repo access
Recommended Workflow Pairing:View Scenario →

q402-mcp + Scenario Prompt → Complete Agent Automation

MCP hands-on: install to visible results

Follow the full lab (expected UI/output + contrast checks). After installing this item, verify with the tutorial prompts.

Open tutorial →

Related resources

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Unified Manifest

{
  "id": "io.github.quackai-org/q402-mcp",
  "type": "mcp-server",
  "version": "0.11.33",
  "displayName": "q402-mcp",
  "description": "Q402 - gasless payments, yield, escrow, bridge & NAV triggers on 12 EVM chains. Sandbox-default.",
  "repository": {
    "url": "https://github.com/quackai-org/q402-mcp",
    "source": "github"
  },
  "distribution": {
    "packages": [
      {
        "registryType": "npm",
        "identifier": "@quackai/q402-mcp",
        "version": "0.11.33",
        "transport": "stdio",
        "environmentVariables": [
          {
            "name": "Q402_TRIAL_API_KEY",
            "description": "Recommended path: skip this UI and run `q402_doctor` after install - it stores secrets in ~/.q402/mcp.env, which the server auto-loads. Fill this field directly ONLY if your MCP client manages secrets for you. Value is a Free Trial API key from https://q402.quackai.ai/event - BNB Chain (permanent) + Base (permanent) + Mantle limited-time (2026-08-21~08-28 UTC+9), 500 sponsored TXs, gas covered by Q402. Avalanche trial has ended. BNB and Base payments auto-route to this key when set (same rule for q402_pay and q402_batch_pay up to 5 recipients).",
            "isSecret": true
          },
          {
            "name": "Q402_MULTICHAIN_API_KEY",
            "description": "Recommended path: skip this UI and run `q402_doctor` after install - it stores secrets in ~/.q402/mcp.env, which the server auto-loads. Fill this field directly ONLY if your MCP client manages secrets for you. Value is a Paid Multichain API key from https://q402.quackai.ai/payment - full 12-chain support with per-chain Gas Tank. Auto-routed for non-BNB payments and whenever keyScope='multichain' is chosen.",
            "isSecret": true
          },
          {
            "name": "Q402_PRIVATE_KEY",
            "description": "Mode A - real EOA signing. Hex-encoded EVM private key (0x + 64 hex chars) of YOUR MetaMask wallet, used to sign payment authorizations LOCALLY on your machine. After your first payment that wallet shows as 'Smart account' in MetaMask (EIP-7702 delegation, reversible via q402_clear_delegation). Use a fresh wallet, not your main one. Skip this and pick Mode B (Q402_AGENTIC_PRIVATE_KEY) or Mode C (server-managed Agent Wallet) if you'd rather keep your MetaMask untouched. Recommended path: run q402_doctor after install - it stores secrets in ~/.q402/mcp.env, which the server auto-loads.",
            "isSecret": true
          },
          {
            "name": "Q402_AGENTIC_PRIVATE_KEY",
            "description": "Mode B - local Agent Wallet signing. Hex-encoded EVM private key (0x + 64 hex chars) exported from your Agent Wallet at https://q402.quackai.ai/dashboard -> Agent tab -> Export. Signs LOCALLY just like Mode A, but the signer is your dedicated Agent Wallet - your MetaMask EOA is never touched. Pick this for AI-agent automation when you want a dedicated purse with per-tx + daily caps you set on the dashboard.",
            "isSecret": true
          },
          {
            "name": "Q402_ENABLE_REAL_PAYMENTS",
            "description": "Live-mode switch. 0 = sandbox (test mode, no funds move - every q402_pay returns a fake hash). 1 = real on-chain payments. Default 1 since v0.5.11: safe because mode only flips to live when a live API key (q402_live_*) is set AND one of (a) a valid 32-byte private key for local signing modes, OR (b) walletMode=\"agentic-server\" with Q402_MULTICHAIN_API_KEY for the server-managed Agent Wallet path. Without either combination, the server stays in sandbox regardless of this flag."
          },
          {
            "name": "Q402_MAX_AMOUNT_PER_CALL",
            "description": "Per-call USD-equivalent cap for USDC/USDT/RLUSD. Any such q402_pay request with amount above this is rejected before signing. Q (QuackAI) is exempt by design (your own token; recipient allowlist + confirmation still apply). Lower this for a tighter agent blast-radius; raise for treasury-grade transfers."
          },
          {
            "name": "Q402_ALLOWED_RECIPIENTS",
            "description": "Optional comma-separated lowercase EVM addresses. When set, q402_pay rejects any recipient not on this allowlist."
          },
          {
            "name": "Q402_RELAY_BASE_URL",
            "description": "Override for the Q402 relay endpoint. Defaults to https://q402.quackai.ai/api. Set explicitly when running against a self-hosted Q402 deployment or a non-canonical environment."
          },
          {
            "name": "Q402_AGENT_WALLET_ADDRESS",
            "description": "Server-managed Agent Wallet picker (walletMode='agentic-server' only). Lowercased agent wallet address (the hex 0x... shown on the Agent tab of your dashboard) selecting which of your Agent Wallets to spend from when you hold more than one (max 10 per owner). Omit to use the default wallet. Ignored for the local-signing modes that carry their own private key."
          },
          {
            "name": "Q402_API_KEY",
            "description": "DEPRECATED legacy single-key env from pre-v0.5.0 installs. The server still reads it as a silent fallback so existing setups keep working, but new users should pick a scoped variant instead. Q402_TRIAL_API_KEY (Free Trial, BNB Chain + Base) and Q402_MULTICHAIN_API_KEY (full 12-chain surface) are designed to coexist - BNB and Base payments auto-route to the trial key, other chains use multichain. Only set Q402_API_KEY if you are migrating an existing pre-v0.5.0 install; do NOT set it alongside the scoped variants on a fresh install.",
            "isSecret": true
          },
          {
            "name": "Q402_WALLET_ID",
            "description": "DEPRECATED soft-migration alias for Q402_AGENT_WALLET_ADDRESS (one release of overlap from v0.6.0). The server still accepts it but logs a deprecation notice. New installs should set Q402_AGENT_WALLET_ADDRESS directly."
          },
          {
            "name": "Q402_BUILDER_CODE",
            "description": "Optional Base Builder Code for onchain attribution (ERC-8021 / Base Builder Codes). When set, every q402_x402_fetch payment includes your code as the client/intermediary in the x402 payment extension so payments are attributed onchain. Format: 1-32 lowercase letters, numbers, or underscores. Leave unset to disable attribution."
          }
        ]
      }
    ],
    "remotes": []
  },
  "dependencies": [],
  "installTargets": [
    "claude-code",
    "claude-desktop",
    "cursor",
    "vscode",
    "trae",
    "cherry-studio",
    "lingma",
    "windsurf",
    "cline",
    "workbuddy"
  ],
  "keywords": [],
  "provenance": {
    "origin": "official-mcp-registry",
    "originalId": "io.github.quackai-org/q402-mcp",
    "originalUrl": "https://registry.modelcontextprotocol.io/v0.1/servers/io.github.quackai-org%2Fq402-mcp/versions/latest",
    "isOfficial": true,
    "status": "active"
  }
}
q402 MCP Setup & Guide - AgentHub