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Overview

Payo-enabled MCP servers need your agent token to process payments. How you pass this token depends on the transport your MCP client uses.

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Transport Methods

TransportToken MethodCommon Clients
stdioEnvironment variableClaude Code, Claude Desktop, Cursor
HTTPAuthorization headerCustom agents, web apps

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stdio Transport

Most MCP clients spawn MCP servers as subprocesses. Pass your token as an environment variable.
Use the Claude CLI to add MCP servers with your token.For HTTP servers:
claude mcp add weather-api --transport http https://mcp.example.com/mcp \
  --header "Authorization: Bearer sk_live_your_token_here"
For stdio servers:
claude mcp add weather-api -- npx @example/weather-mcp
Then set the environment variable:
export AGENT_TOKEN=sk_live_your_token_here
Or add it to your shell profile (~/.bashrc, ~/.zshrc).

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HTTP Transport

If your agent connects to MCP servers over HTTP, pass the token in the Authorization header. 
const response = await fetch('https://mcp.example.com/mcp', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': 'Bearer sk_live_your_token_here'
  },
  body: JSON.stringify({
    jsonrpc: '2.0',
    method: 'tools/call',
    params: {
      name: 'get_weather',
      arguments: { city: 'New York' }
    },
    id: 1
  })
});

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Using MCP Client Libraries

If you’re using an MCP client library, configure the auth header: 
import { Client } from '@modelcontextprotocol/sdk/client/index.js';
import { StreamableHTTPClientTransport } from '@modelcontextprotocol/sdk/client/streamableHttp.js';

const transport = new StreamableHTTPClientTransport(
  new URL('https://mcp.example.com/mcp'),
  {
    requestInit: {
      headers: {
        'Authorization': 'Bearer sk_live_your_token_here'
      }
    }
  }
);

const client = new Client({ name: 'my-agent', version: '1.0.0' });
await client.connect(transport);

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Multiple Servers

You can use the same token for multiple MCP servers: 
{
  "mcpServers": {
    "weather": {
      "command": "npx",
      "args": ["-y", "@example/weather-mcp"],
      "env": { "AGENT_TOKEN": "sk_live_abc123" }
    },
    "data": {
      "command": "npx",
      "args": ["-y", "@example/data-mcp"],
      "env": { "AGENT_TOKEN": "sk_live_abc123" }
    }
  }
}
All charges go to the same account balance.

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Verifying Your Setup

To verify your token is configured correctly:
  1. Call a free tool first (if available) to confirm connectivity
  2. Call a paid tool and check your wallet for the charge
  3. If you see TOKEN_MISSING, your token isn’t reaching the server

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Troubleshooting

The server didn’t receive your token. Check:
  • Environment variable name is exactly AGENT_TOKEN
  • Value includes the full key (starts with sk_live_)
  • Config file syntax is valid JSON
  • You restarted your MCP client after changes
The token was received but is invalid. Check:
  • Key wasn’t deleted from your dashboard
  • No typos or missing characters
  • Key is from the correct Payo account
Your token is valid but you need more credits. Check:
  • Your current balance in the Wallet page
  • Deposit more funds (or contact [email protected] during beta)
This isn’t a Payo error. Check:
  • The MCP server URL/command is correct
  • Server is running and accessible
  • No firewall blocking the connection