WA Lookup
01

What is MCP?

The Model Context Protocol is an open standard that lets AI applications call external tools during a conversation. Once connected, you can ask your assistant to check a number or review a batch without writing a separate API integration.

MCP is a protocol adapter, not a separate validation system. It uses the same products, balance, billing, rate limits, concurrency limits, and result semantics as the REST API.
02

Authentication

Use the exact same API key you use for the REST API. Create or copy it from Settings, then add it as a Bearer token in your MCP client configuration.

Authorization header
Authorization: Bearer YOUR_API_KEY
Keep your API key private

Only add the key to your own trusted client configuration. Never paste it into a public prompt, commit it to source control, or expose it in browser code.

03

Server URL

The server uses the official Streamable HTTP transport. Point your client to this single endpoint; no local MCP process is required.

MCP endpointhttp://localhost:14003/mcp

Requests use JSON-RPC over Streamable HTTP and are authenticated by the same API-key middleware as the REST endpoints.

04

Connect your client

Choose the configuration format your client supports. Replace the placeholder with your API key.

Claude Code

Add the remote server from your terminal.

claude mcp add --transport http wachecker https://walookup.com/mcp --header "Authorization: Bearer YOUR_API_KEY"

Cursor / Claude Desktop

Add this server entry to the client's MCP configuration.

{
  "mcpServers": {
    "wachecker": {
      "url": "https://walookup.com/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

Other MCP clients

Use Streamable HTTP with the endpoint and Bearer header above.

URL: https://walookup.com/mcp
Authorization: Bearer YOUR_API_KEY
05

Available tools

The tools are scoped to the app that owns your API key. Call list_products first when you need to discover valid product codes.

list_products

Lists the products available to this API key, including prices, billing multipliers, purposes, and response fields.

No parameters
check_number

Checks one submitted phone number synchronously. registered is the primary result; avatar and business are optional product fields.

service_type · string · required
identifier · string · required
check_numbers

Checks 1–100 numbers with one service_type. Results preserve input order; each number is evaluated independently and a failed number does not stop the rest.

service_type · string · required
identifiers · string[] · required · max 100
get_balance

Reads the current account balance. It is read-only and does not create a check or charge the account.

No parameters

Example prompts

After connecting, ask your assistant in plain language:

  • “Check whether +14155552671 is registered on WhatsApp.”
  • “Check these 20 numbers and summarize registered versus unregistered results.”
  • “Show the products available to my API key and their prices.”
  • “How much balance is left before I run this batch?”
06

Error handling

Tool failures are returned with isError=true so the client can explain what happened instead of treating the connection as broken. Business failures use the same code, msg, data contract as the API.

Example tool error
{
  "code": 42900,
  "msg": "rate limit exceeded",
  "data": null
}
40100

Missing or invalid API key

Check the Bearer header and confirm the key is active in Settings.

40200

Insufficient balance

Check the balance or top up before retrying. A batch is rejected before processing when the full amount cannot be covered.

42900 / 42901

Rate or concurrency limit

Batch usage is counted by number, not by request. Wait for the window or in-flight checks to clear before retrying.

40000 / 40002

Invalid product or number

Use a service_type returned by list_products and send the phone number you want to check.

42200 / 50300

Undetermined or temporary service failure

Do not classify the number as unregistered. Keep it pending and retry later; failed or undetermined checks do not keep the charge.

Ready to connect your AI assistant?

Create an account, copy your API key, and start checking from your preferred MCP client.

Create a free accountView REST API docs