MCP All-in-One Server

by Arnie936

Overview Schema Source Related Servers Discussions Admin

Python

Local

add

Compute the sum of two numbers. Provide two numeric inputs to perform addition.

Instructions

Add two numbers

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

Implementation Reference

calculator_server/server.py:182-184 (handler)
The 'add' tool handler function that adds two numbers. Decorated with @mcp.tool() and returns the sum of a and b.
```
def add(a: float, b: float) -> float:
    """Add two numbers"""
    return a + b
```
calculator_server/server.py:181-181 (registration)
The @mcp.tool() decorator that registers the add function as an MCP tool.
```
@mcp.tool()
```

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0May 16, 2026

TDQS

A4/5.0

Behavior4/5

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

No annotations are provided, so the description carries the full burden. 'Add two numbers' transparently describes a pure arithmetic operation with no side effects or hidden behavior. It does not mention edge cases, but none are necessary for a simple addition tool.

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 four words, front-loaded with the operation, and contains zero extraneous information. Every word earns its place.

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

Completeness5/5

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

For a trivial arithmetic tool with an output schema present, the description fully covers what an agent needs to know. There are no dependencies, side effects, or error cases that require explanation.

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

Parameters2/5

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

Schema description coverage is 0%, yet the description adds no meaning beyond the schema: 'two numbers' merely restates that both parameters are numbers. It does not explain the role of each parameter or any format constraints, so it fails to compensate for the lack of schema descriptions.

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 'Add two numbers' uses a specific verb and resource, clearly distinguishing this tool from siblings like subtract, multiply, and divide. An agent can immediately understand the operation without opening the schema.

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 usage when addition is needed, but it gives no explicit context for when to choose this over alternatives. There is no mention of when to use add versus subtract/multiply/divide, though the intent is obvious for such a basic operation.

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

Deploy Server

add