Is the Moon Calendar MCP server safe?

No scan can promise that. What its definitions show: 8 tools, all of which only read, and 0 findings from fixed checks. Read-only tools can still pass private data to a model.

Can the Moon Calendar MCP server delete data?

No tool is classed as destructive: going by their definitions, none of them deletes, cancels or revokes anything.

Can the Moon Calendar MCP server do things that cannot be undone?

No tool is classed as irreversible: none of them sends, pays, publishes or merges, going by their definitions.

What tools does the Moon Calendar MCP server have?

8 tools: 8 read. get_moon, find_moon_events, get_moon_calendar, list_eclipses, plan_dark_skies, get_tides, get_moon_sign and check_crescent_visibility.

Does the Moon Calendar MCP server need sign-in or OAuth?

Its remote endpoint listed its tools to an anonymous client, without sign-in.

Does the Moon Calendar MCP server send data to outside services?

None of its tools sends, posts or publishes, or takes a recipient, channel or URL.

Has the Moon Calendar MCP server changed its tools?

Not since anlyon.dev started tracking it. Last scanned Nov 7, 2026.

Moon Calendar MCP server

uk.co.mooncalendar/mooncalendar-co-ukmooncalendar.co.ukstreamable-httpv1.1.0Scanned 8 days ago

Moon phases, full and new Moon dates, UK moonrise, eclipses, dark skies, tides and Moon sign.

8 tools: 8 only read.

Reads private data · 2
Reads text others write · 1
Can send data out · 0
No findings

Tools listed without sign-in. Remote posture

With Anlyon

Decide which of this server's tools your agent can use.

Anlyon lists the tools and adopts none.
Each tool you adopt gets approvals and receipts.
Your agent never holds the key.

Govern this server →

A tool your agent calls directly is not routed through Anlyon and is not governed by it. anlyon.dev only lists and labels, and these labels are the same either way.

What the Moon Calendar MCP server can do

The Moon Calendar MCP server is published by mooncalendar.co.uk, a domain the MCP Registry verified. It has 8 tools. Every one of them only reads: going by their definitions, none of them creates, changes, sends or deletes anything.

2 tools read private data (get_moon_calendar and list_eclipses); 1 tool brings in text other people can write (get_moon_sign).

None of the fixed checks matched anything in its tool definitions. That is not a safety guarantee.

Its remote endpoint lists its tools without sign-in.

Last scanned Nov 7, 2026, version 1.1.0.

Tools

Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.

8 tools

Only reads 8Looks things up and changes nothing.Show 8 read-only tools

check_crescent_visibilityReturns the first three evenings after a new Moon with a crescent sighting verdict (likely, difficult or not visible) for each of 24 UK places, with sunset, moonset, Moon age, heig…No findings
Why it is in this group
- The description's first verb is "return": a word for reading.
Description, as the server wrote it
Returns the first three evenings after a new Moon with a crescent sighting verdict (likely, difficult or not visible) for each of 24 UK places, with sunset, moonset, Moon age, height and best viewing time. It covers the latest new Moon until its third evening is over, then the next one.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
- title: New crescent Moon sighting
find_moon_eventsReturns the dates and UK times of upcoming full, new, first quarter and last quarter Moons, with each full Moon's traditional name, its distance, and supermoon, blue Moon, micromoo…No findings
Why it is in this group
- The name "find_moon_events" says "find": a word for reading.
Description, as the server wrote it
Returns the dates and UK times of upcoming full, new, first quarter and last quarter Moons, with each full Moon's traditional name, its distance, and supermoon, blue Moon, micromoon and black Moon flags. Special Moons can be listed on their own.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
- title: Moon phase dates
get_moonReturns the Moon's phase, percent lit, lunar age, distance from Earth and waxing or waning direction right now, at 12:00 UK time on a date, or at a UK clock time on a date.No findings
Why it is in this group
- The name "get_moon" says "get": a word for reading.
Description, as the server wrote it
Returns the Moon's phase, percent lit, lunar age, distance from Earth and waxing or waning direction right now, at 12:00 UK time on a date, or at a UK clock time on a date. Also returns whether it is a full Moon, the next full and new Moon, and at a UK place that date's moonrise, highest point and moonset, the Moon's height and compass bearing, and whether it is above the horizon after dark. Times are UK time, GMT or BST.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
- title: Moon on a date
get_moon_calendarReturns every day of one UK calendar month with its Moon phase and percent lit at 12:00 UK time, plus the exact UK times of that month's new, first quarter, full and last quarter M…Reads private dataNo findings
Why it is in this group
- The name "get_moon_calendar" says "get": a word for reading.
What it can reach
- private-dataThe name "get_moon_calendar" says "get" and "calendar": it reads calendars.
- private-dataThe description's first sentence says "return" and "calendar": it reads calendars.
Description, as the server wrote it
Returns every day of one UK calendar month with its Moon phase and percent lit at 12:00 UK time, plus the exact UK times of that month's new, first quarter, full and last quarter Moons.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
- title: Moon calendar for a month
get_moon_signReturns the Moon's zodiac sign right now, on a UK date or at a UK date and time, tropical or Lahiri sidereal, with the degree into the sign, the next sign change and the website's …Reads text others writeNo findings
Why it is in this group
- The name "get_moon_sign" says "get": a word for reading.
What it can reach
- untrusted-inputThe description's first sentence says "return" and "website": it reads web pages, which anyone can write.
Description, as the server wrote it
Returns the Moon's zodiac sign right now, on a UK date or at a UK date and time, tropical or Lahiri sidereal, with the degree into the sign, the next sign change and the website's one-line meaning of the sign. With a date alone it returns every sign the Moon is in that day.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
- title: Moon sign
get_tidesReturns the dates and UK times of spring tides (new and full Moons) and neap tides (first and last quarter Moons) from the Moon's phases, in date order, with the next spring tide a…No findings
Why it is in this group
- The name "get_tides" says "get": a word for reading.
Description, as the server wrote it
Returns the dates and UK times of spring tides (new and full Moons) and neap tides (first and last quarter Moons) from the Moon's phases, in date order, with the next spring tide and next neap tide first and perigean spring tides flagged. These are tide dates, not times or heights for a port.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
- title: Spring and neap tide dates
list_eclipsesReturns upcoming solar and lunar eclipses in date order with the UK peak time, the kind of eclipse and what the UK sees of it, including London contact times, coverage or totality …Reads private dataNo findings
Why it is in this group
- The name "list_eclipses" says "list": a word for reading.
What it can reach
- private-dataThe description's first sentence says "return" and "contact": it reads contacts.
Description, as the server wrote it
Returns upcoming solar and lunar eclipses in date order with the UK peak time, the kind of eclipse and what the UK sees of it, including London contact times, coverage or totality where the Sun or Moon is above the horizon. With a place, each eclipse also shows that place's start, maximum and end, the share of the Sun covered or the Moon's height.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
- title: Eclipses seen from the UK
plan_dark_skiesReturns the nights of one UK month with a dark-sky window, when the Sun is more than 18° below the horizon and the Moon is down, at one of 24 UK places, with each night's window ti…No findings
Why it is in this group
- The description's first verb is "return": a word for reading.
Description, as the server wrote it
Returns the nights of one UK month with a dark-sky window, when the Sun is more than 18° below the horizon and the Moon is down, at one of 24 UK places, with each night's window times, hours and Moon phase. For photography it returns each night's Moon window, when the Moon is at least 5° up while the Sun is more than 6° below the horizon. Times are UK time, GMT or BST.
Annotations the server declares
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
- title: Dark-sky and Moon photography nights

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.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

No private-data, untrusted-input, outbound path in this server alone: no tool is tagged outbound.

Reads private data2: Reads files, mail, messages, databases, secrets, calendars or repositories.; get_moon_calendar
list_eclipses
Reads text others write1: Brings in text someone else can write: web pages, inbound email, messages, issues and comments.; get_moon_sign
Can send data out0: Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Remote posture

What anyone on the internet sees at the remote endpoint: an anonymous initialize and tools/list, and the public OAuth metadata.

Tools listed without sign-in

Looked at Nov 14, 2026, 12:21 UTC, unchanged since Nov 7, 2026. No credentials were sent and no tool was called. What is looked at.

Reachable: yes
HTTP status of an anonymous initialize: 200
tools/list served without credentials: yes
Tools that change things, listed without credentials: 0
Protocol version: 2025-06-18
WWW-Authenticate on 401: not observed
resource_metadata in WWW-Authenticate: not observed
RFC 9728 protected resource metadata: not observed
Authorization servers: not observed
Legacy HTTP+SSE transport: no
Dynamic client registration: not observed
Client ID metadata documents: not observed

Findings

Matches of fixed checks, with the text they matched.

No check matched anything in these tool definitions. That is not a safety guarantee.

History

Changes to its tool definitions and to its remote endpoint, newest first.

No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.

All changes to this server

Install

Pinned to version 1.1.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http mooncalendar-co-uk https://mooncalendar.co.uk/api/mcp

claude mcp add --transport http mooncalendar-co-uk https://mooncalendar.co.uk/api/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json

{
  "permissions": {
    "allow": [
      "mcp__mooncalendar-co-uk__get_moon",
      "mcp__mooncalendar-co-uk__find_moon_events",
      "mcp__mooncalendar-co-uk__get_moon_calendar",
      "mcp__mooncalendar-co-uk__list_eclipses",
      "mcp__mooncalendar-co-uk__plan_dark_skies",
      "mcp__mooncalendar-co-uk__get_tides",
      "mcp__mooncalendar-co-uk__get_moon_sign",
      "mcp__mooncalendar-co-uk__check_crescent_visibility"
    ],
    "ask": [],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as mooncalendar-co-uk. Review it before you use it.

Capability tags behind 3 rules

mcp__mooncalendar-co-uk__get_moon_calendar private-data
mcp__mooncalendar-co-uk__list_eclipses private-data
mcp__mooncalendar-co-uk__get_moon_sign untrusted-input

Keep the decision: fail CI when the tools change, follow every change, or show a badge.

Pin in CI

Fail a build when the tools you reviewed are not the tools the server serves today.

curl -s "https://anlyon.dev/api/v1/servers/uk.co.mooncalendar/mooncalendar-co-uk/verify?hash=dfc7b4ef5b142cab213ac61226b42dcdcab3e3a7faff0c80336d1885c161a43e" | jq -e '.changed == false'

Pinned hash dfc7b4ef5b14, from Nov 7, 2026, 04:18 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/uk.co.mooncalendar/mooncalendar-co-uk/changes.xml

An Atom feed. Works in any feed reader or Slack's RSS app.

Badge

[![anlyon.dev](https://anlyon.dev/badge/uk.co.mooncalendar/mooncalendar-co-uk.svg)](https://anlyon.dev/servers/uk.co.mooncalendar/mooncalendar-co-uk)

Source: MCP Registry · repository. Synced Nov 7, 2026, 04:17 UTC.