# Logic Apps ❤️ MCP — Expose Arithmetic Tools (Add & Subtract)

#logicapps #mcp #microsoft #lowcode

Workflows as Arithmetic Tools

You can expose simple arithmetic operations like Add and Subtract as Logic App workflows and register them as MCP tools. With clear trigger descriptions and input metadata, agents can discover and use these tools reliably.

Add Tool (wf_add)

Trigger description: " "
“This tool accepts two integers (number1, number2), adds them, and returns the sum.”

Request schema:

{
  "type": "object",
  "properties": {
    "number1": {
      "type": "integer",
      "description": "First number to add."
    },
    "number2": {
      "type": "integer",
      "description": "Second number to add."
    }
  },
  "required": ["number1", "number2"]
}

Subtract Tool (wf_sub)

Trigger description: " "
“This tool accepts two integers (number1, number2), subtracts number2 from number1, and returns the difference.”

Request schema:

{
  "type": "object",
  "properties": {
    "number1": {
      "type": "integer",
      "description": "Minuend (number1 - number2)."
    },
    "number2": {
      "type": "integer",
      "description": "Subtrahend (to subtract from number1)."
    }
  },
  "required": ["number1", "number2"]
}

Testing Arithmetic MCP Tools with Postman

Postman now supports MCP (Model Context Protocol) as a first-class connection type, which makes testing Logic Apps as MCP servers super easy.

1. Create a new MCP request

In Postman, click New → select MCP.
Enter your MCP server URL:
Hit Connect

2. Discover available tools

Once connected, navigate to the Tools tab in Postman.

Here you’ll see all the available MCP tools exposed by your Logic App (for example, wf_arithmetic_sub and wf_arithmetic_add).

Select wf_arithmetic_sub and provide the inputs: