MCP server

Plumbkit Official

dev.plumbkit/plumbkit

Checked 26 Oct 2026, 08:29 UTC · Connected to it and listed its tools

Exact utilities for agents: time zones, date math, business days, calculator, units, validation.

Website

At a glance

Type

MCP server

Publisher

plumbkit.dev (verified by the MCP Registry)

Status

Working at last check

Tools

16

Token cost

About 3,714 tokens per request

Sets up in

Claude Code, Claude Desktop, Codex, Gemini CLI, Cursor, VS Code, Antigravity, ChatGPT, OpenAI API, Grok

Last checked

26 Oct 2026, 08:29 UTC

Connect it to your agent

Add to CursorAdd to VS CodeVS Code Insiders

Opens the app, which shows the server and asks you to confirm. For other apps, copy the setup below.

Claude Code

claude mcp add --transport http plumbkit https://plumbkit.dev/mcp

Claude Desktop

Settings → Connectors → Add custom connector, and paste the URL.

Codex (config.toml)

[mcp_servers.plumbkit]
url = "https://plumbkit.dev/mcp"

Gemini CLI

{"mcpServers":{"plumbkit":{"httpUrl":"https://plumbkit.dev/mcp"}}}

Cursor

{"mcpServers":{"plumbkit":{"url":"https://plumbkit.dev/mcp"}}}

VS Code

{"servers":{"plumbkit":{"type":"http","url":"https://plumbkit.dev/mcp"}}}

Antigravity

agy mcp add plumbkit https://plumbkit.dev/mcp

ChatGPT

Settings → Apps & Connectors → Advanced settings: turn on Developer mode, then Create a connector and paste the URL. Which plans can do this varies.

OpenAI API (Responses tools)

{"type":"mcp","server_label":"plumbkit","server_url":"https://plumbkit.dev/mcp","require_approval":"always"}

Grok (xAI API tools)

{"type":"mcp","server_label":"plumbkit","server_url":"https://plumbkit.dev/mcp"}

Tools

• business_days ~392 tokens
  Works with business (working) days. mode "add": returns the date N business days after start_date (start_date itself is not counted; negative N goes backward; 0 returns start_date, or the next business day if start_date is not one). mode "count": counts business days from start_date to end_date, inc
• calculate ~216 tokens
  Evaluates an arithmetic expression exactly, so you don't have to do mental math. Supports + - * / % ^ (or **), parentheses, constants pi/e/tau and functions: sqrt, cbrt, abs, round(x, digits), floor, ceil, trunc, sign, ln, log(x[, base]), log10, log2, exp, pow, sin, cos, tan, asin, acos, atan, atan2
• convert_timezone ~280 tokens
  Converts a date/time from one time zone to another, correctly handling daylight saving time. If the input already includes an offset or 'Z', from_timezone is ignored.
• convert_units ~216 tokens
  Converts a value between units of length, mass, volume (US and imperial), area, speed, time, digital data (KB vs KiB, bits vs bytes), energy, pressure and temperature. Accepts common abbreviations (km, lb, fl oz, mph, °F, GiB). US customary units are used for cup/pint/quart/gallon unless you say imp
• current_time ~157 tokens
  Returns the exact current date, time, weekday and UTC offset in any time zone. Use this whenever you need to know today's date or the current time instead of guessing — your training data does not know what day it is.
• date_add ~491 tokens
  Adds or subtracts a duration (years, months, weeks, days, hours, minutes, seconds) to a date/time. Use negative numbers to subtract. Calendar-aware: adding 1 month to Jan 31 gives Feb 28/29, and adding days keeps the same local clock time across daylight-saving changes.
• date_diff ~310 tokens
  Calculates the exact time between two dates/times: a calendar breakdown (years, months, days, hours, minutes, seconds) plus totals in days, hours, minutes and seconds, and the number of calendar days. Negative if end is before start.
• hash_text ~157 tokens
  Computes a cryptographic hash (SHA-1, SHA-256, SHA-384, SHA-512) of text, or encodes/decodes it as Base64, Base64URL, hex or URL-encoding. Text is treated as UTF-8.
• json_repair ~171 tokens
  Turns almost-JSON into valid JSON: removes markdown code fences, comments and trailing commas, adds missing quotes, commas and closing brackets, converts single quotes, Python True/False/None and truncated output. Returns the repaired JSON string and whether the input was already valid.
• json_schema_validate ~192 tokens
  Checks a JSON value against a JSON Schema (drafts 4, 7, 2019-09 and 2020-12) and lists every violation with its location. Use it to confirm structured output or an API payload is correct before sending it. `data` and `schema` may be JSON values or JSON strings.
• regex_test ~277 tokens
  Runs a JavaScript regular expression against text and returns every match with its position and capture groups, or the text after replacement. Use it to verify a regex actually works before relying on it.
• text_stats ~247 tokens
  Counts exactly what language models are bad at counting: characters (as humans see them), words, lines, sentences, paragraphs, UTF-8 bytes, and occurrences of a letter or substring (e.g. how many "r" in "strawberry"). Use it to check length limits (tweets, SMS, meta descriptions, form fields) before
• validate_email Sends messages · ~152 tokens
  Checks whether an email address is correctly formatted and returns a normalized version. Set check_dns=true to also confirm the domain exists and can receive mail (MX records). Does not send email and cannot confirm that a specific mailbox exists.
• validate_iban ~116 tokens
  Validates an International Bank Account Number: country, length for that country, and the mod-97 check digits. Returns electronic and printed formats. A valid IBAN is correctly formed; this does not confirm the account exists.
• validate_phone ~176 tokens
  Validates a phone number using Google's libphonenumber rules and returns it in E.164 (+14155552671), international and national formats, plus the country and line type (mobile, fixed line, toll free...). For numbers without a +country code, pass default_country.
• validate_url ~164 tokens
  Checks that a URL is well-formed, normalizes it (lowercase host, punycode, default ports removed, spaces encoded) and splits it into parts including each query parameter. Flags common problems such as missing scheme, private/localhost addresses and credentials embedded in the URL. Does not fetch the

Browse

• Converting to Markdown
• Email
• SMS and text messages
• Calendars

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