add
Add two numbers
LABSCO SUMMARY
Arithmetic stops being something the model does in its head and becomes something you can read back.
Each operation is its own call over numeric arguments, so a multi-step figure leaves a trace with the steps named: this number came out of mul, that one out of div. The scope is those operations and nothing else — no expressions, no precedence, no variables — so anything compound has to be sequenced by the caller, one call per step.
What it is
A six-tool arithmetic server — a separate call per operation, each taking bare numeric arguments rather than an expression.
What you get
- The four basic operations as separate calls: add, sub, mul and div, each over two numbers
- mod, returning one number modulo the other
- sqrt, which takes a single number rather than a pair
Requirements
Nothing to supply: no account, no key, and no service behind it — the arithmetic happens in the server.
Setup effort
One command — npx -y @wrtnlabs/calculator-mcp@latest
USE CASES
01
Keeping a multi-step total defensible
Do each step as its own call — the line total, the running sum, the deduction — so the figure at the end has the arithmetic behind it on record.
02
Splitting a quantity that does not divide evenly
Take the whole part with div and the leftover with mod, instead of asking the model to hold both in one answer.
03
Working back from an area to the side that produced it
Send the single number through sqrt rather than letting an estimate stand in for the root.
6 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
div
Divide two numbers
mod
Mod two numbers
mul
Multiply two numbers
sqrt
Square root of a number
sub
Subtract two numbers
BEFORE YOU INSTALL
What to know first
Tools you get
6 tools when we connected.
Requires
npx on PATH
CONTEXT COST
Light Standing cost
Rated by the size of the 6 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Add the block to your client, or run the command directly.
Server setup
Configuration file
JSON
{
"mcpServers": {
"calculator-mcp": {
"command": "npx",
"args": [
"-y",
"@wrtnlabs/calculator-mcp@latest"
]
}
}
}npx
TERMINAL
npx -y @wrtnlabs/calculator-mcp@latest
