# lihtness/gnomon-mcp [Health: Active]

**Category:** 🧮 Data Science Tools  
**Repository:** https://github.com/lihtness/gnomon-mcp  
**GitHub Stars:** 1  
**Views:** 4  
**Installs:** 0  
**Upvotes:** 0  
**Directory Page:** https://allmcps.com/mcp/lihtness-gnomon-mcp

## Description
Deterministic batch tools so LLM agents stop next-token-guessing dates and math. Rich now() snapshot (18 fields), calendar(ops) batch dispatcher (diff/until/since/add/weekday/businessdays, natural-language parsing), calc(expressions) Python eval with math+stats pre-loaded, and Pint-based unit conversion. One wiring for dates + math + units. Listed in the official MCP Server Registry. uvx gnomon-mcp.

## Claude Desktop Quick Installation
Install path detected from listing signals. Uses `uvx` (confidence: high):

```json
"mcpServers": {
  "gnomon-mcp": {
    "command": "uvx",
    "args": ["gnomon-mcp"]
  }
}
```

## Documentation

## What lihtness/gnomon-mcp MCP server does

The lihtness/gnomon-mcp MCP server gives agents deterministic utilities for dates, calendars, arithmetic, and unit conversion. It is intended for cases where approximate reasoning can produce an incorrect answer, such as calculating elapsed time, adding months across calendar boundaries, evaluating decimals, or converting physical quantities.

The server exposes a standalone `now` tool that returns an 18-field snapshot of the current moment. The result includes ISO time, date and clock fields, Unix time, timezone, weekday information, day-of-year, ISO week, quarter, US government fiscal year, and a weekend flag. A timezone can be supplied.

## How it works

MCP clients communicate with the server over standard input and output. The `calendar` tool accepts a list of operations and returns results in the same order, allowing one request to process multiple rows or unrelated date calculations. Supported operations include `diff`, `until`, `since`, `add`, `weekday`, `business_days`, `parse`, and `format`.

Date inputs can be known timestamps or natural-language expressions such as “next Thursday” and “in 3 hours.” Difference and elapsed-time operations support seconds, minutes, hours, days, and weeks. Calendar-aware month and year addition are available through `add`. Business-day counting covers Monday through Friday, with the start date included and the end date excluded.

The `calc` tool also accepts a list and evaluates Python expressions in order. Common math functions and constants, statistical functions such as `mean` and `median`, and selected built-ins including `sum`, `range`, `sorted`, `min`, and `max` are preloaded. `calc_convert` uses Pint for conversions such as meters to feet, kilograms to pounds, and Celsius to Fahrenheit.

## Setup and configuration

The recommended launch command is:

```bash
uvx gnomon-mcp
```

This runs the package on demand without a separate installation. The package can alternatively be installed with `pip install gnomon-mcp`, after which the `gnomon-mcp` executable can be used directly. The repository also documents a `--demo` mode that invokes each tool once and prints results without requiring an MCP client.

The README includes configuration examples for Claude Code and Claude Desktop. No API key, account credential, or environment variable is specified for operation.

## Tools and capabilities

- `now(tz?)`: returns the current-time snapshot.
- `calendar(ops)`: batches date calculations and formatting operations.
- `calc(expressions)`: evaluates multiple Python expressions.
- `calc_convert(value, from_unit, to_unit)`: converts quantities with Pint.

Batch input is useful for applying the same kind of calculation to every row in a table while preserving result order. The lihtness/gnomon-mcp MCP server combines date, math, and unit functions behind one MCP connection rather than requiring separate utility servers.

## Limitations and notes

The business-day operation excludes weekends but does not account for public holidays. The README describes `calc` as float-based and notes that it is not suitable for currency calculations requiring decimal arithmetic and explicit rounding. Proposed features such as holiday-aware calendars, regex processing, token counting, hashing, and cron support are not implemented tools in the current server.

_Full upstream README: https://allmcps.com/mcp/lihtness-gnomon-mcp/readme_