Calc Mcp
Gives Claude 21 local tools for operations where LLMs reliably fail: arbitrary precision math evaluation, cryptographically secure random generation (UUID v4/v7, ULID, passwords), timezone-aware date arithmetic, and hash computation (SHA-256, HMAC, etc.). Also handles base64/URL/HTML encoding, regex operations with ReDoS protection, semantic versioning comparisons, JWT decoding, cron parsing, Luhn validation, and IP range analysis. Everything runs sandboxed on your machine via stdio transport. Reach for this when you need deterministic calculations, true randomness, or format operations that can't hallucinate. Works with Claude Desktop, VS Code Copilot, Cursor, and Windsurf out of the box.
- GitHub stars
- 9
- tools
- 21
- transport
- STDIO
- last updated
- Oct 24, 2026
Tools
21 toolsPublic tool metadata for what this MCP can expose to an agent.
mathEvaluate expressions, statistics
Evaluate expressions, statistics
No parameter schema in public metadata yet.
countCharacters (grapheme-aware), words, lines, bytes
Characters (grapheme-aware), words, lines, bytes
No parameter schema in public metadata yet.
datetimeCurrent time, timezone conversion, UNIX timestamps
Current time, timezone conversion, UNIX timestamps
No parameter schema in public metadata yet.
randomUUID v4/v7, ULID, passwords (readable, custom charset), random number, shuffle
UUID v4/v7, ULID, passwords (readable, custom charset), random number, shuffle
No parameter schema in public metadata yet.
hashMD5, SHA-1, SHA-256, SHA-512, CRC32, HMAC
MD5, SHA-1, SHA-256, SHA-512, CRC32, HMAC
No parameter schema in public metadata yet.
base64Encode / decode
Encode / decode
No parameter schema in public metadata yet.
encodeURL, HTML entity, Unicode escape
URL, HTML entity, Unicode escape
No parameter schema in public metadata yet.
dateDiff, add/subtract, weekday, wareki
Diff, add/subtract, weekday, wareki
No parameter schema in public metadata yet.
regexTest, match, matchAll, replace
Test, match, matchAll, replace
No parameter schema in public metadata yet.
baseNumber base conversion (2–36)
Number base conversion (2–36)
No parameter schema in public metadata yet.
diffLine diff, Levenshtein distance
Line diff, Levenshtein distance
No parameter schema in public metadata yet.
format_validateValidate JSON, CSV, XML, YAML
Validate JSON, CSV, XML, YAML
No parameter schema in public metadata yet.
cron_parseHuman-readable cron + next runs (weekday/month names supported)
Human-readable cron + next runs (weekday/month names supported)
No parameter schema in public metadata yet.
luhnValidate / generate check digits
Validate / generate check digits
No parameter schema in public metadata yet.
ipIPv4/IPv6 info, CIDR contains check, range calculation
IPv4/IPv6 info, CIDR contains check, range calculation
No parameter schema in public metadata yet.
colorHEX ↔ RGB ↔ HSL (alpha channel supported)
HEX ↔ RGB ↔ HSL (alpha channel supported)
No parameter schema in public metadata yet.
convert8 categories, 146 unit names: length, weight, temperature, area (tsubo, tatami), volume, speed, data, time
8 categories, 146 unit names: length, weight, temperature, area (tsubo, tatami), volume, speed, data, time
No parameter schema in public metadata yet.
char_infoUnicode code point, block, category
Unicode code point, block, category
No parameter schema in public metadata yet.
jwt_decodeDecode header + payload (no verification)
Decode header + payload (no verification)
No parameter schema in public metadata yet.
url_parseProtocol, host, path, params, hash
Protocol, host, path, params, hash
No parameter schema in public metadata yet.
semverCompare, validate, parse, range satisfaction
Compare, validate, parse, range satisfaction
No parameter schema in public metadata yet.
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Calc MCP
📖 Documentation — Full tool reference, examples, and install guides.
21 tools for things AI is not good at — deterministic math, cryptographic randomness, accurate date arithmetic, encoding, hashing, and more.
LLMs hallucinate calculations, can't generate true random numbers, and struggle with timezones. This MCP server fixes that.
Quick Start
# Claude Code
claude mcp add -s user calc-mcp -- npx -y @coo-quack/calc-mcp@2.1.5
# Or just run it
npx -y @coo-quack/calc-mcp@2.1.5
Works with Claude Desktop, VS Code Copilot, Cursor, Windsurf, and any MCP client — setup guides below.
Why?
Details
- Repository
- github.com/coo-quack/calc-mcp
- Package
@coo-quack/calc-mcp- Transport
- STDIO
- Registry
- MCP registry, active