Spend Guard MCP

Spend Guard is an MCP server that acts as a spending guard for AI agents paying for APIs in USDC. It enforces budgets, payee allowlists, and price-spike checks, requiring human approval via a dashboard before any USDC is signed or transferred. It supports payments on Circle's Arc testnet and NEAR testnet, protecting agents from prompt injection or malicious paywall changes.

Package and access

Local package with source-attributed installation metadata. Koskamo does not execute packages during review.

Community listingLocal stdioSource reviewed; not executedPublished by vulinh1704

Vendor documentation

What you can do with it

Enforce budget limits for AI agent API payments
Check for price spikes before signing transactions
Require human approval for unusual payments
Validate payee allowlists to prevent address swapping

Source and maintenance

Community listingRegistry 0.2.0

mcp-registry: io.github.vulinh1704/spend-guard@0.2.0 Source repository Project website

Maintenance checked: Oct 31, 2026, 10:59 PM UTC

Packages and installation

Source-provided package data. Koskamo has not executed or live-probed this package.

@vulinh1704/spend-guard 0.2.0

npmnpx

@vulinh1704/spend-guard package definition

{
  "version": "0.2.0",
  "transport": "stdio",
  "identifier": "@vulinh1704/spend-guard",
  "runtimeHint": "npx",
  "registryType": "npm",
  "registryBaseUrl": "https://registry.npmjs.org",
  "packageArguments": [
    {
      "type": "positional",
      "value": "mcp"
    }
  ],
  "environmentVariables": [
    {
      "name": "SPEND_GUARD_POLICY",
      "format": "filepath",
      "description": "Policy JSON file: networks, budgets, approval amount, spike ratio, known services and their payees. Without one, every payment waits for your approval."
    },
    {
      "name": "SPEND_GUARD_RAILS",
      "default": "mock",
      "description": "How to pay: mock (pays nothing), near, arc, gateway, or a comma list. arc and gateway need ARC_PRIVATE_KEY, near needs NEAR_ACCOUNT_ID and NEAR_PRIVATE_KEY."
    },
    {
      "name": "SPEND_GUARD_LEDGER",
      "format": "filepath",
      "description": "Decisions file, read back on start so a restart keeps today's spend; servers on one file share one budget. Default ~/.spend-guard/ledger.jsonl; off keeps it in memory."
    },
    {
      "name": "SPEND_GUARD_DASHBOARD_PORT",
      "default": "4400",
      "description": "Port of the approval dashboard on 127.0.0.1. 0 picks a free one; off means no dashboard, and payments that need approval are declined."
    },
    {
      "name": "SPEND_GUARD_APPROVAL_TIMEOUT",
      "format": "number",
      "default": "55",
      "description": "Seconds a payment waits for your answer before it is declined. Raise it together with your client's tool timeout."
    },
    {
      "name": "SPEND_GUARD_MOCK_NETWORK",
      "default": "near-testnet",
      "description": "Network the mock rail pretends to pay on."
    },
    {
      "name": "ARC_PRIVATE_KEY",
      "description": "Agent key for the arc and gateway rails. Testnet keys only."
    },
    {
      "name": "NEAR_ACCOUNT_ID",
      "description": "Agent account for the near rail (testnet)."
    },
    {
      "name": "NEAR_PRIVATE_KEY",
      "description": "Agent key for the near rail. Testnet keys only."
    }
  ]
}

Tools

Reported by the attributed source; not independently observed by Koskamo.

No tool definitions available.

Connect from your client

Each snippet configures the same source-provided package; replace placeholders before use.

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Cursor

Merge this local stdio configuration, replace every placeholder environment value, and restart Cursor. Koskamo has not executed this package.

Cursor configuration

{
  "mcpServers": {
    "spend-guard-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@vulinh1704/spend-guard@0.2.0",
        "mcp"
      ],
      "env": {
        "SPEND_GUARD_POLICY": "<YOUR_SPEND_GUARD_POLICY>",
        "SPEND_GUARD_RAILS": "<YOUR_SPEND_GUARD_RAILS>",
        "SPEND_GUARD_LEDGER": "<YOUR_SPEND_GUARD_LEDGER>",
        "SPEND_GUARD_DASHBOARD_PORT": "<YOUR_SPEND_GUARD_DASHBOARD_PORT>",
        "SPEND_GUARD_APPROVAL_TIMEOUT": "<YOUR_SPEND_GUARD_APPROVAL_TIMEOUT>",
        "SPEND_GUARD_MOCK_NETWORK": "<YOUR_SPEND_GUARD_MOCK_NETWORK>",
        "ARC_PRIVATE_KEY": "<YOUR_ARC_PRIVATE_KEY>",
        "NEAR_ACCOUNT_ID": "<YOUR_NEAR_ACCOUNT_ID>",
        "NEAR_PRIVATE_KEY": "<YOUR_NEAR_PRIVATE_KEY>"
      }
    }
  }
}

Cline

Merge this local stdio configuration, replace every placeholder environment value, and restart Cline. Koskamo has not executed this package.

Cline configuration

{
  "mcpServers": {
    "spend-guard-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@vulinh1704/spend-guard@0.2.0",
        "mcp"
      ],
      "env": {
        "SPEND_GUARD_POLICY": "<YOUR_SPEND_GUARD_POLICY>",
        "SPEND_GUARD_RAILS": "<YOUR_SPEND_GUARD_RAILS>",
        "SPEND_GUARD_LEDGER": "<YOUR_SPEND_GUARD_LEDGER>",
        "SPEND_GUARD_DASHBOARD_PORT": "<YOUR_SPEND_GUARD_DASHBOARD_PORT>",
        "SPEND_GUARD_APPROVAL_TIMEOUT": "<YOUR_SPEND_GUARD_APPROVAL_TIMEOUT>",
        "SPEND_GUARD_MOCK_NETWORK": "<YOUR_SPEND_GUARD_MOCK_NETWORK>",
        "ARC_PRIVATE_KEY": "<YOUR_ARC_PRIVATE_KEY>",
        "NEAR_ACCOUNT_ID": "<YOUR_NEAR_ACCOUNT_ID>",
        "NEAR_PRIVATE_KEY": "<YOUR_NEAR_PRIVATE_KEY>"
      }
    }
  }
}

VS Code

Merge this local stdio configuration, replace every placeholder environment value, and restart VS Code. Koskamo has not executed this package.

VS Code configuration

{
  "servers": {
    "spend-guard-mcp": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@vulinh1704/spend-guard@0.2.0",
        "mcp"
      ],
      "env": {
        "SPEND_GUARD_POLICY": "<YOUR_SPEND_GUARD_POLICY>",
        "SPEND_GUARD_RAILS": "<YOUR_SPEND_GUARD_RAILS>",
        "SPEND_GUARD_LEDGER": "<YOUR_SPEND_GUARD_LEDGER>",
        "SPEND_GUARD_DASHBOARD_PORT": "<YOUR_SPEND_GUARD_DASHBOARD_PORT>",
        "SPEND_GUARD_APPROVAL_TIMEOUT": "<YOUR_SPEND_GUARD_APPROVAL_TIMEOUT>",
        "SPEND_GUARD_MOCK_NETWORK": "<YOUR_SPEND_GUARD_MOCK_NETWORK>",
        "ARC_PRIVATE_KEY": "<YOUR_ARC_PRIVATE_KEY>",
        "NEAR_ACCOUNT_ID": "<YOUR_NEAR_ACCOUNT_ID>",
        "NEAR_PRIVATE_KEY": "<YOUR_NEAR_PRIVATE_KEY>"
      }
    }
  }
}

Claude Desktop

Merge this local stdio configuration, replace every placeholder environment value, and restart Claude Desktop. Koskamo has not executed this package.

Claude Desktop configuration

{
  "mcpServers": {
    "spend-guard-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@vulinh1704/spend-guard@0.2.0",
        "mcp"
      ],
      "env": {
        "SPEND_GUARD_POLICY": "<YOUR_SPEND_GUARD_POLICY>",
        "SPEND_GUARD_RAILS": "<YOUR_SPEND_GUARD_RAILS>",
        "SPEND_GUARD_LEDGER": "<YOUR_SPEND_GUARD_LEDGER>",
        "SPEND_GUARD_DASHBOARD_PORT": "<YOUR_SPEND_GUARD_DASHBOARD_PORT>",
        "SPEND_GUARD_APPROVAL_TIMEOUT": "<YOUR_SPEND_GUARD_APPROVAL_TIMEOUT>",
        "SPEND_GUARD_MOCK_NETWORK": "<YOUR_SPEND_GUARD_MOCK_NETWORK>",
        "ARC_PRIVATE_KEY": "<YOUR_ARC_PRIVATE_KEY>",
        "NEAR_ACCOUNT_ID": "<YOUR_NEAR_ACCOUNT_ID>",
        "NEAR_PRIVATE_KEY": "<YOUR_NEAR_PRIVATE_KEY>"
      }
    }
  }
}

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