Calculator MCP Server

add

Computes the sum of two numeric inputs and returns the result as a string.

Instructions

Add two numbers together.

Args: a: The first number. b: The second number.

Returns: A string with the sum of a and b.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "a": "<a>",
      "b": "<b>"
    },
    "name": "add"
  }
}

Input Schema

Name	Required	Description	Default
`a`	Yes
`b`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 8, 2026

TDQS

A4/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description states a return value ('A string with the sum of a and b') and implies no side effects. However, the stated return type is suspicious for a numeric addition, so the behavioral disclosure is present but potentially inaccurate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise: one purpose sentence, two parameter lines, and one return line. No irrelevant information is included, and the structure makes each component easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple two-number addition tool, the description provides the essential information needed to call it correctly. It omits edge cases and constraints, but those are not necessary for this level of complexity; the only notable gap is the questionable return type.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema only provides numeric types, but the description adds roles for both parameters: 'a: The first number' and 'b: The second number'. This compensates for the schema's lack of descriptions, though it adds no constraints or edge-case semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description begins with 'Add two numbers together', a specific verb and resource that clearly identifies the operation. This distinguishes it from sibling arithmetic tools like subtract, multiply, divide, power, square_root, and percentage.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies use when an addition or sum is needed but does not explicitly contrast with sibling tools or state when not to use it. The name and operation are unambiguous enough for a simple arithmetic tool, so the guidance is adequate but implicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

add