luhn
Validate / generate check digits
How to use it
Project documentation lists luhn for the Calc MCP MCP server. Add the server to your MCP client (Claude Desktop, Cursor, Windsurf and others), then check which tools your installed version makes available. Tool availability can depend on configuration and credentials. A server handshake does not verify this tool’s behavior. See the full listing for setup details.
Install Calc MCP
claude mcp add -s user calc-mcp -- npx -y @coo-quack/calc-mcp@2.1.0Other tools in Calc MCP (20)
Number base conversion (2–36)
Encode / decode
Unicode code point, block, category
HEX ↔ RGB ↔ HSL (alpha channel supported)
8 categories, 146 unit names: length, weight, temperature, area (tsubo, tatami), volume, speed, data, time
Characters (grapheme-aware), words, lines, bytes
Human-readable cron + next runs (weekday/month names supported)
Diff, add/subtract, weekday, wareki
Current time, timezone conversion, UNIX timestamps
Line diff, Levenshtein distance
URL, HTML entity, Unicode escape
Validate JSON, CSV, XML, YAML
MD5, SHA-1, SHA-256, SHA-512, CRC32, HMAC
IPv4/IPv6 info, CIDR contains check, range calculation
Decode header + payload (no verification)
Evaluate expressions, statistics
UUID v4/v7, ULID, passwords (readable, custom charset), random number, shuffle
Test, match, matchAll, replace
Compare, validate, parse, range satisfaction
Protocol, host, path, params, hash