calc_subnet
Calculate subnet details (network, broadcast, usable hosts, mask) from a CIDR like 192.168.1.0/24
cidr必填
io.github.headlessherm-creator由 GitHub 账号 headlessherm-creator 发布v3.1.0更新于 Oct 29, 2026
Local deterministic calc MCP: exact math, dates, unit conversion, stats, subnet math.
本地 MCP 服务器,为助手提供精确确定性的数学、日期、单位换算、统计、子网与 UUID 工具,全程不联网。
Desktop only,通过 STDIO。 STDIO 服务会启动本地进程,因此需要 SourceWeft 桌面宿主。
参照 仓库 中的启动说明。
A free, local, 16-tool MCP server that gives AI agents exact, deterministic answers for math, date arithmetic, unit conversion, subnet/networking calculations, statistics, token counting, and real random UUID generation — no network calls, no API keys, no telemetry.
If your AI agent is miscounting days between dates, rounding large numbers incorrectly, getting unit conversions slightly wrong, or messing up subnet/CIDR math, this MCP server exists specifically to fix that class of problem.
Local and open-weight models (Llama, Qwen, Mistral, etc.) are consistently unreliable at exact math, date arithmetic, unit conversion, and similar deterministic tasks — they "reason" their way to an answer instead of computing it, and get it subtly wrong. (Frontier hosted models like Claude and GPT-4 already handle most of this correctly unaided — this toolkit is aimed at closing the gap for smaller/local models, not replacing what those already do well.) Every tool here uses classical deterministic methods instead of model reasoning, so the answer is always exactly right.
Everyday things it fixes:
More technical tools:
Most AI dev tool MCP servers either charge a subscription or call out to a remote API. This one never touches the network. Every tool is pure local computation, verifiable directly in the source: open src/tools.js — there is no fetch or http import anywhere in it.
1. Install Node.js (v18+) if you don't have it: https://nodejs.org
2. Clone this repo and install dependencies:
3. Point your MCP client at the local path:
Add that to your MCP client's config and restart it. Setup docs for common clients:
calculate (arbitrary-precision expression evaluator),
factorial, permutations, combinations (all arbitrary-precision, avoid float64
overflow), compute_statistics (mean, median, stdev, variance, percentiles)date_add, date_diff (leap years, month boundaries, business
days handled correctly), convert_timezoneconvert_unit (length, weight, volume, temperature), convert_base
(decimal, hex, binary, octal)calc_subnet (CIDR math), check_ip_type (private/reserved range
lookup)levenshtein_distance (exact edit distance and similarity ratio)haversine_distance (exact great-circle distance between coordinates)count_tokens (GPT tokenizer, for managing context budget before
a large prompt), generate_uuid (real cryptographically-random v4 UUIDs, 1-100 at a time)@modelcontextprotocol/sdk: the MCP protocol implementationzod: input schema validationmathjs: arbitrary-precision math evaluationgpt-tokenizer: GPT tokenizer for count_tokensAll installed automatically by npm install. None of them make network calls at runtime.
deterministic math MCP server, MCP date calculator, MCP unit converter, subnet CIDR calculator MCP, local MCP server no API key, Claude MCP math tools, AI agent exact arithmetic, token counter MCP server.
Same local-first philosophy, different problems:
MIT
来源:README.md,提交 4e2f25a
Calculate subnet details (network, broadcast, usable hosts, mask) from a CIDR like 192.168.1.0/24
cidr必填Check if an IPv4 address is private/reserved and identify which range it falls in
ip必填Evaluate an arbitrary-precision math expression exactly (fixes LLM multi-digit arithmetic errors). Supports +,-,*,/,^,sqrt(),sin(),log(), etc.
expression必填Count tokens in text using the GPT-3.5/4 (cl100k_base) tokenizer. Useful for managing context budget before sending a large prompt
text必填Add or subtract days/weeks/months/years/businessDays from a date, handling leap years and month boundaries correctly
date必填unit必填amount必填Compute the exact difference between two dates in days, business days, and hours
a必填b必填Convert a UTC/ISO date into a formatted date+time string for any IANA time zone
date必填timeZone必填Compute mean, median, stdev, variance, min/max, and percentiles (25/75/90) for a list of numbers
numbers必填Convert a value between units of length, weight, volume, or temperature (fixes LLM unit-math errors)
value必填toUnit必填fromUnit必填Compute exact great-circle distance in km/miles between two lat/long coordinates
lat1必填lat2必填lon1必填lon2必填Compute n! exactly using arbitrary-precision integer math (avoids float64 overflow past ~18)
n必填Compute nPr (permutations) exactly using arbitrary-precision integer math
n必填r必填Compute nCr (combinations) exactly using arbitrary-precision integer math
n必填r必填Convert a number between decimal, hex, binary, and octal
value必填toBase必填fromBase必填Compute exact edit distance and similarity ratio between two strings (deterministic fuzzy matching)
a必填b必填Generate real cryptographically-random UUIDs (v4). Fixes LLMs fabricating plausible-looking but non-random, potentially colliding UUID strings instead of real random ones.
count已满足适用检查项的 90%
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git clone https://github.com/headlessherm-creator/polymath-megablaster-mcp.gitcd polymath-megablaster-mcpnpm install{ "mcpServers": { "polymath": { "command": "node", "args": ["/absolute/path/to/polymath-megablaster-mcp/src/index.js"] } }}