FabTally Utility Belt
by zvmzaretsky · remote · no sign-in to list tools · v1.0.0 · published by GitHub user zvmzaretsky
13 deterministic agent utilities: timezone, cron, RRULE, currency, regex, diff, hashing & more.
Final · 3Changes · 9
13 tools: 3 do something that can't be undone, 9 change things and 1 only read.
Scanned Oct 21, 2026
- Deletes or cancels0Claude Code: deny
- Can't be undone3Claude Code: ask: see these tools
- Changes things9Claude Code: ask: see these tools
- Only reads1Claude Code: allow: see these tools
No check matched anything in the tool definitions. No finding is not a safety guarantee. How the checks work.
claude mcp add --transport http utility-belt https://belt.fabtally.com/mcpTools
Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.
13 tools
Can't be undone 3Claude Code: ask
convertFREE.No findings
Why it is in this group
- The name "convert" says "convert": a word for a change.
- The input addresses people (input.to): what it sends cannot be taken back.
Description, as the server wrote it FREE. Convert a value between units in the same dimension: length, mass, temperature, volume, data, time, area, speed, angle, pressure, energy. Deterministic. Args: value (number), from (unit), to (unit). e.g. {value:100, from:'c', to:'f'} or {value:1, from:'GiB', to:'MB'}. Different-dimension conversions 400.
currencyPAID $0.001.No findings
Why it is in this group
- The input addresses people (input.to): what it sends cannot be taken back.
Description, as the server wrote it PAID $0.001. Convert an amount between currencies at reference/mid-market rates from a keyless public central-bank feed (ECB), cached. Informational, not a dealable quote. Args: amount, from, to (ISO-4217, e.g. USD, EUR, JPY). Without payment returns the x402 challenge; pass x_payment to settle.
datemathPAID $0.001.No findings
Why it is in this group
- The input addresses people (input.to): what it sends cannot be taken back.
Description, as the server wrote it PAID $0.001. Calendar date math. op='add'/'subtract' an ISO-8601 duration (P1Y2M10DT2H30M) to a date; op='diff' two datetimes into chosen units; op='business-add' add business days (configurable weekend + holidays); op='business-diff' count business days between two dates. Without payment returns the x402 challenge; pass x_payment to settle.
Changes things 9Claude Code: ask
cronPAID $0.001.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it PAID $0.001. Parse a 5- or 6-field cron expression and return the next N run times plus a plain-English description. Args: expression, timezone (IANA, default UTC), count (default 5), from (ISO, optional). Without payment returns the x402 challenge; pass x_payment to settle.
encodeFREE.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it FREE. Encode or decode text. op is one of base64-encode|base64-decode|base64url-encode|base64url-decode|hex-encode|hex-decode|url-encode|url-decode|html-encode|html-decode. Args: op, text.
hashFREE.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it FREE. Compute a cryptographic digest: sha256, sha512, sha384, sha1, md5, sha3-256, keccak256, ripemd160. Optional HMAC via hmac_key. Output hex (default), base64, or base64url. keccak256 also returns a 0x-form (handy for Ethereum). Args: algorithm, text (+ input_encoding utf8|hex|base64, output_encoding, hmac_key).
idFREE.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it FREE. Generate identifiers. kind is one of uuidv4|uuidv7|ulid|nanoid|hex|base64url|int. count up to 1000. nanoid takes `size`; hex/base64url take `bytes`. Uses a CSPRNG. Args: kind, count.
jsonschemaPAID $0.001.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it PAID $0.001. Validate a value against a JSON Schema (draft 2020-12) and explain every error in plain English (which property, what was wrong, allowed values). Args: schema (object), data (any). Without payment returns the x402 challenge; pass x_payment to settle.
regexFREE.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it FREE. Run a regular expression against input with catastrophic-backtracking protection (it runs in a killable worker with a hard timeout, so a pathological pattern returns a 400 instead of hanging). op is test|match|extract|replace. Args: pattern, input, flags (gimsuy), op, replacement (for replace).
rrulePAID $0.001.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it PAID $0.001. Expand an iCal RRULE (RFC 5545) recurrence into its next N occurrences. Args: rrule (e.g. 'FREQ=WEEKLY;BYDAY=MO,WE;COUNT=10'), after (ISO, default now), count (default 5), timezone. Tip: include DTSTART for anchored series. Without payment returns the x402 challenge; pass x_payment.
textFREE.No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it FREE. Text transforms. op='slugify' -> URL slug; op is one of camel|pascal|snake|kebab|constant|dot|path|title|sentence|upper|lower for case conversion; op='template' fills {{placeholders}} from `data`. Args: op, text (for slugify/case), or template + data (for template).
timezonePAID $0.001 (x402, USDC on Base).No findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
Description, as the server wrote it PAID $0.001 (x402, USDC on Base). Convert an instant between IANA time zones with historically-correct DST. Returns converted datetime, UTC offsets, tz abbreviations, DST flags, and the offset difference. Args: datetime (ISO 8601 or epoch), from_zone, to_zone. Without payment returns the x402 challenge; pass x_payment to settle. Free teaser exists on the HTTP API at /v1/timezone/free.
Only reads 1Claude Code: allow
diffPAID $0.001.No findings
Why it is in this group
- The name "diff" says "diff": a word for reading.
Description, as the server wrote it PAID $0.001. Diff two texts: a unified patch, a structured op-list (add/remove/equal), and add/remove/hunk stats. Args: a, b, mode (lines|words|chars, default lines), context (default 3), label_a, label_b. Without payment returns the x402 challenge; pass x_payment to settle.
This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.
Install
Pinned to version 1.0.0. Values in angle brackets are yours to fill in.
claude mcp add --transport http utility-belt https://belt.fabtally.com/mcpRun in a terminal.
Claude Code permissions
Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.
{
"permissions": {
"allow": [
"mcp__utility-belt__diff"
],
"ask": [
"mcp__utility-belt__convert",
"mcp__utility-belt__text",
"mcp__utility-belt__hash",
"mcp__utility-belt__encode",
"mcp__utility-belt__id",
"mcp__utility-belt__regex",
"mcp__utility-belt__timezone",
"mcp__utility-belt__cron",
"mcp__utility-belt__rrule",
"mcp__utility-belt__currency",
"mcp__utility-belt__jsonschema",
"mcp__utility-belt__datemath"
],
"deny": []
}
}Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as utility-belt. Review it before you use it.