A Rust port of calc (Landon Curt Noll's arbitrary-precision calculator)
About
A Rust port of calc (Landon Curt Noll's arbitrary-precision calculator) that works as:
Explore
- ✅ User-defined functions (define name(params) = expr)
- ✅ Control flow (if/else, while, for loops)
- ✅ Variables and scoping
- ✅ Lists and indexing (0-based, negative indices supported)
- ✅ Complex numbers with full arithmetic
- ✅ String literals and operations
- ✅ Base conversion (2-36, input and output)
- ✅ Arbitrary-precision arithmetic (exact rationals)
- ✅ File loading (-f filename)
- ✅ REPL, pipe mode, quiet mode
Setting up with Highlight
This MCP is not yet compatible with Highlight’s one-click setup. However, you can still use it with Highlight by following these steps:
- Download and install Highlight from highlightai.com/download
- Navigate to the plugins tab and select "Add Custom Plugin"
-
Configure the plugin with the settings below
Plugin Name
A Rust port of calc (Landon Curt Noll's arbitrary-precision calculator)Command (node, npx, python, etc.)Please refer to the README for specific instructions on how to obtain API keys or other required environment variables.
- Enable "Start Automatically" if you want the plugin to start when Highlight launches
From the repository
rcalc '2^100' # 1267650600228229401496703205376
rcalc '1/3 + 1/6' # 0.5
rcalc -m frac '1/3 + 1/6' # 1/2
rcalc 'gcd(462,1071)' # 21
rcalc 'fact(30)' # 265252859812191058636308480000000
rcalc 'sqrt(2)' # 1.4142135623730950488
rcalc 'isprime(1000003)' 'nextprime(1000003)' # 1 \n 1000033
echo '3*4' | rcalc -p # pipe mode
rcalc # interactive REPL (Ctrl-D to exit)
Flags: -p pipe mode, -q quiet, -m real|frac|int, -v version, -h help.
Several classic calc flags (-c -C -d -e -i -O -s -u) are accepted and ignored.
cargo build --release
./target/release/rcalc-web
toRustCalcMCP --mcp # speak JSON-RPC 2.0 over stdio
``
Handshake →
initialize, then tools/list, then tools/call. See
docs/MCP_TOOL_SCHEMA.json for the authoritative,
server-emitted schema and examples/mcp-config.json`for a client registration snippet.
calc_eval
evaluate an expression
calc_config
get/set session precision & display
calc_functions
list builtins
| tool | purpose | key args |
|------|---------|----------|
| calc_eval | evaluate an expression | expression (req), mode, digits, epsilon |
| calc_config | get/set session precision & display | action (get/set), mode, digits, epsilon |
| calc_functions | list builtins | filter (optional substring) |
calc_eval's mode/digits/epsilon are per-call overrides; calc_config set
changes them for the session.
Claude Desktop / Cursor
Paste into your MCP client config file to install this server.
{
"mcpServers": {
"a rust port of calc (landon curt noll's arbitrary-precision calculator)": {
"toRustCalcMCP": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"ghcr.io/carlomagnoglobal/torustcalcmcp:latest"
]
}
}
}
}McpServers
{
"toRustCalcMCP": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"ghcr.io/carlomagnoglobal/torustcalcmcp:latest"
]
}
}toRustCalcMCP
A Rust port of calc (Landon Curt Noll's
arbitrary-precision calculator) that works as:
- rcalc — a calc-compatible command-line calculator
- Web REPL — browser-based interactive calculator
- MCP server — JSON-RPC 2.0 over stdio for LLM/agent integration
Three interfaces, one engine. The numeric core uses exact rational arithmetic
(num-rational over num-bigint), which is the same model calc uses natively —
so 1/3 * 3 is exactly 1, and 2^256 is computed to the last digit.
👉 Getting Started in 2 minutes — new to rcalc? Start here.
👉 Install as Claude Desktop MCP — integrate with Claude Desktop.
Build
```sh
cargo build --release
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