MCPVault

jwt_decode

MCP tool from Calc MCP by coo-quack

Decode header + payload (no verification)

How to use it

jwt_decode is exposed by the Calc MCP MCP server. Add the server to your MCP client (Claude Desktop, Cursor, Windsurf and others), and the jwt_decode tool becomes available to the model automatically. See the full listing for setup details and every tool this server provides.

Install Calc MCP

$claude mcp add -s user calc-mcp -- npx -y @coo-quack/calc-mcp@2.1.0
FULL CALC MCP LISTING

Other tools in Calc MCP (20)

base

Number base conversion (2–36)

base64

Encode / decode

char_info

Unicode code point, block, category

color

HEX ↔ RGB ↔ HSL (alpha channel supported)

convert

8 categories, 146 unit names: length, weight, temperature, area (tsubo, tatami), volume, speed, data, time

count

Characters (grapheme-aware), words, lines, bytes

cron_parse

Human-readable cron + next runs (weekday/month names supported)

date

Diff, add/subtract, weekday, wareki

datetime

Current time, timezone conversion, UNIX timestamps

diff

Line diff, Levenshtein distance

encode

URL, HTML entity, Unicode escape

format_validate

Validate JSON, CSV, XML, YAML

hash

MD5, SHA-1, SHA-256, SHA-512, CRC32, HMAC

ip

IPv4/IPv6 info, CIDR contains check, range calculation

luhn

Validate / generate check digits

math

Evaluate expressions, statistics

random

UUID v4/v7, ULID, passwords (readable, custom charset), random number, shuffle

regex

Test, match, matchAll, replace

semver

Compare, validate, parse, range satisfaction

url_parse

Protocol, host, path, params, hash