astroway-mcp

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by astroway

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TypeScript

Remote

Moon Phase (SVG)

astroway_render_moon_phase

Read-onlyIdempotent

Render the moon disk at a specific date, time, and location to show its illuminated fraction, returning an SVG and illumination metrics.

Instructions

Render the moon disk with its illuminated fraction at the given moment. Returns SVG plus illumination metrics.

[Group: Visualization] [Endpoint: POST /v1/render/moon-phase] [Cost: 10 credits (Tier 1)]

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "body": "<body>"
    },
    "name": "astroway_render_moon_phase"
  }
}

Input Schema

Name	Required	Description	Default
`body`	Yes	Birth data for a single natal chart. Required: date (YYYY-MM-DD), time (HH:mm:ss), latitude and longitude in decimal degrees. The short forms lat, lon, lng and tz are rejected with 400 INVALID_FIELD; pass the full names. timezoneOffset is hours from UTC and defaults to 0, meaning UTC; send timezone instead (an IANA name such as Europe/Kyiv, or auto) and the offset for that date is worked out, summer time included. city is a display label only: nothing here geocodes it, so it never stands in for coordinates. houseSystem is a single house-system letter, P by default; a name such as "Placidus" is refused, and the case matters because I and i are two different Sunshine systems.

Output Schema

Name	Required	Description	Default
`svg`	No
`phase`	No
`waxing`	No
`elongationDeg`	No
`illuminationFraction`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv1.6.1Nov 9, 2026

changedInput schema / properties / body / allOf

Previous value: -[
-  {
-    "additionalProperties": {
-      "anyOf": [
-        {},
-        {
-          "type": "null"
-        }
-      ]
-    },
-    "description": "Birth data for a single natal chart. Required: date (YYYY-MM-DD), time (HH:mm:ss), latitude and longitude in decimal degrees. The short forms lat, lon, lng and tz are rejected with 400 INVALID_FIELD; pass the full names. timezoneOffset is hours from UTC and defaults to 0, meaning UTC; send timezone instead (an IANA name such as Europe/Kyiv, or auto) and the offset for that date is worked out, summer time included. city is a display label only: nothing here geocodes it, so it never stands in for coordinates. houseSystem is a single Swiss Ephemeris letter, P by default; a name such as \"Placidus\" is refused, and the case matters because I and i are two different Sunshine systems.",
-    "properties": {
-      "ayanamsa": {
-        "description": "Sidereal school by name. Lahiri when omitted. Equivalent to ayanamsaId; send either.",
-        "enum": [
-          "fagan-bradley",
-          "lahiri",
-          "de-luce",
-          "raman",
-          "krishnamurti",
-          "kp",
-          "yukteshwar",
-          "jn-bhasin",
-          "true-citra",
-          "djwhal-khul"
-        ],
-        "type": "string"
-      },
-      "ayanamsaId": {
-        "type": [
-          "number",
-          "null"
-        ]
-      },
-      "city": {
-        "default": "",
-        "type": "string"
-      },
-      "cosmogram": {
-        "type": "boolean"
-      },
-      "date": {
-        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
-        "type": "string"
-      },
-      "houseSystem": {
-        "default": "P",
-        "enum": [
-          "P",
-          "K",
-          "R",
-          "C",
-          "E",
-          "W",
-          "B",
-          "M",
-          "O",
-          "A",
-          "T",
-          "V",
-          "D",
-          "F",
-          "G",
-          "H",
-          "I",
-          "i",
-          "L",
-          "N",
-          "Q",
-          "S",
-          "U",
-          "X",
-          "Y"
-        ],
-        "type": "string"
-      },
-      "latitude": {
-        "maximum": 90,
-        "minimum": -90,
-        "type": "number"
-      },
-      "longitude": {
-        "maximum": 180,
-        "minimum": -180,
-        "type": "number"
-      },
-      "name": {
-        "default": "",
-        "type": "string"
-      },
-      "time": {
-        "pattern": "^\\d{2}:\\d{2}(:\\d{2})?$",
-        "type": "string"
-      },
-      "timezone": {
-        "description": "IANA zone name such as Europe/Kyiv, or auto to look the zone up from latitude and longitude. The server takes the offset that zone kept at this local date and time, summer time included, and uses it in place of timezoneOffset. A clock time that happened twice takes the first occurrence; one skipped when clocks went forward takes the offset from before the change. Abbreviations such as EST are refused. Before 1970 the tz database is not reliable for every place, so send timezoneOffset when the local clock is known.",
-        "type": "string"
-      },
-      "timezoneOffset": {
-        "anyOf": [
-          {
-            "maximum": 14,
-            "minimum": -14,
-            "type": "number"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "default": 0,
-        "description": "Hours from UTC at the given moment, not minutes. Fractional zones are hours too: 5.5 for India, 5.75 for Nepal, -3.5 for Newfoundland. Defaults to 0, meaning UTC. Ignored when timezone is sent."
-      },
-      "zodiacType": {
-        "enum": [
-          "tropical",
-          "sidereal"
-        ],
-        "type": "string"
-      }
-    },
-    "required": [
-      "date",
-      "time",
-      "latitude",
-      "longitude"
-    ],
-    "type": "object"
-  },
-  {
-    "additionalProperties": {
-      "anyOf": [
-        {},
-        {
-          "type": "null"
-        }
-      ]
-    },
-    "properties": {
-      "options": {
-        "properties": {
-          "format": {
-            "default": "json",
-            "enum": [
-              "svg",
-              "json"
-            ],
-            "type": "string"
-          },
-          "showAspects": {
-            "type": "boolean"
-          },
-          "showLabel": {
-            "type": "boolean"
-          },
-          "showRetrograde": {
-            "type": "boolean"
-          },
-          "size": {
-            "maximum": 2000,
-            "minimum": 200,
-            "type": "integer"
-          },
-          "theme": {
-            "description": "css paints every colour as var(--aw-<role>, <light colour>), so the page that inlines the SVG can recolour it with CSS custom properties (--aw-chart-bg, --aw-fg, --aw-muted, --aw-ring, --aw-houses-fill, --aw-benefic, --aw-malefic, --aw-aspect-harmonious, --aw-aspect-tense, --aw-aspect-neutral, --aw-aspect-minor, --aw-aspect-quintile, --aw-moon-shadow, --aw-moon-light, --aw-cycle-physical, --aw-cycle-emotional, --aw-cycle-intellectual). With none set it looks exactly like light. Inside an <img> the variables cannot be set, so it stays light. The Western wheels and the aspect grid then also carry stable aw-* classes, and each planet is a <g> with data-planet and data-label, each aspect line has data-a and data-b; see the @astroway/render changelog for the list.",
-            "enum": [
-              "light",
-              "dark",
-              "console",
-              "css"
-            ],
-            "type": "string"
-          },
-          "title": {
-            "maxLength": 120,
-            "type": "string"
-          }
-        },
-        "type": "object"
-      }
-    },
-    "type": "object"
-  }
-]New value: +[
+  {
+    "additionalProperties": {
+      "anyOf": [
+        {},
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "description": "Birth data for a single natal chart. Required: date (YYYY-MM-DD), time (HH:mm:ss), latitude and longitude in decimal degrees. The short forms lat, lon, lng and tz are rejected with 400 INVALID_FIELD; pass the full names. timezoneOffset is hours from UTC and defaults to 0, meaning UTC; send timezone instead (an IANA name such as Europe/Kyiv, or auto) and the offset for that date is worked out, summer time included. city is a display label only: nothing here geocodes it, so it never stands in for coordinates. houseSystem is a single house-system letter, P by default; a name such as \"Placidus\" is refused, and the case matters because I and i are two different Sunshine systems.",
+    "properties": {
+      "ayanamsa": {
+        "description": "Sidereal school by name. Lahiri when omitted. Equivalent to ayanamsaId; send either.",
+        "enum": [
+          "fagan-bradley",
+          "lahiri",
+          "de-luce",
+          "raman",
+          "krishnamurti",
+          "kp",
+          "yukteshwar",
+          "jn-bhasin",
+          "true-citra",
+          "djwhal-khul"
+        ],
+        "type": "string"
+      },
+      "ayanamsaId": {
+        "type": [
+          "number",
+          "null"
+        ]
+      },
+      "city": {
+        "default": "",
+        "type": "string"
+      },
+      "cosmogram": {
+        "type": "boolean"
+      },
+      "date": {
+        "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
+        "type": "string"
+      },
+      "houseSystem": {
+        "default": "P",
+        "enum": [
+          "P",
+          "K",
+          "R",
+          "C",
+          "E",
+          "W",
+          "B",
+          "M",
+          "O",
+          "A",
+          "T",
+          "V",
+          "D",
+          "F",
+          "G",
+          "H",
+          "I",
+          "i",
+          "L",
+          "N",
+          "Q",
+          "S",
+          "U",
+          "X",
+          "Y"
+        ],
+        "type": "string"
+      },
+      "latitude": {
+        "maximum": 90,
+        "minimum": -90,
+        "type": "number"
+      },
+      "longitude": {
+        "maximum": 180,
+        "minimum": -180,
+        "type": "number"
+      },
+      "name": {
+        "default": "",
+        "type": "string"
+      },
+      "time": {
+        "pattern": "^\\d{2}:\\d{2}(:\\d{2})?$",
+        "type": "string"
+      },
+      "timezone": {
+        "description": "IANA zone name such as Europe/Kyiv, or auto to look the zone up from latitude and longitude. The server takes the offset that zone kept at this local date and time, summer time included, and uses it in place of timezoneOffset. A clock time that happened twice takes the first occurrence; one skipped when clocks went forward takes the offset from before the change. Abbreviations such as EST are refused. Before 1970 the tz database is not reliable for every place, so send timezoneOffset when the local clock is known.",
+        "type": "string"
+      },
+      "timezoneOffset": {
+        "anyOf": [
+          {
+            "maximum": 14,
+            "minimum": -14,
+            "type": "number"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "default": 0,
+        "description": "Hours from UTC at the given moment, not minutes. Fractional zones are hours too: 5.5 for India, 5.75 for Nepal, -3.5 for Newfoundland. Defaults to 0, meaning UTC. Ignored when timezone is sent."
+      },
+      "zodiacType": {
+        "enum": [
+          "tropical",
+          "sidereal"
+        ],
+        "type": "string"
+      }
+    },
+    "required": [
+      "date",
+      "time",
+      "latitude",
+      "longitude"
+    ],
+    "type": "object"
+  },
+  {
+    "additionalProperties": {
+      "anyOf": [
+        {},
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "properties": {
+      "options": {
+        "properties": {
+          "format": {
+            "default": "json",
+            "enum": [
+              "svg",
+              "json"
+            ],
+            "type": "string"
+          },
+          "showAspects": {
+            "type": "boolean"
+          },
+          "showLabel": {
+            "type": "boolean"
+          },
+          "showRetrograde": {
+            "type": "boolean"
+          },
+          "size": {
+            "maximum": 2000,
+            "minimum": 200,
+            "type": "integer"
+          },
+          "theme": {
+            "description": "css paints every colour as var(--aw-<role>, <light colour>), so the page that inlines the SVG can recolour it with CSS custom properties (--aw-chart-bg, --aw-fg, --aw-muted, --aw-ring, --aw-houses-fill, --aw-benefic, --aw-malefic, --aw-aspect-harmonious, --aw-aspect-tense, --aw-aspect-neutral, --aw-aspect-minor, --aw-aspect-quintile, --aw-moon-shadow, --aw-moon-light, --aw-cycle-physical, --aw-cycle-emotional, --aw-cycle-intellectual). With none set it looks exactly like light. Inside an <img> the variables cannot be set, so it stays light. The Western wheels and the aspect grid then also carry stable aw-* classes, and each planet is a <g> with data-planet and data-label, each aspect line has data-a and data-b; see the @astroway/render changelog for the list.",
+            "enum": [
+              "light",
+              "dark",
+              "console",
+              "css"
+            ],
+            "type": "string"
+          },
+          "title": {
+            "maxLength": 120,
+            "type": "string"
+          }
+        },
+        "type": "object"
+      }
+    },
+    "type": "object"
+  }
+]

changedInput schema / properties / body / description

Previous value: -"Birth data for a single natal chart. Required: date (YYYY-MM-DD), time (HH:mm:ss), latitude and longitude in decimal degrees. The short forms lat, lon, lng and tz are rejected with 400 INVALID_FIELD; pass the full names. timezoneOffset is hours from UTC and defaults to 0, meaning UTC; send timezone instead (an IANA name such as Europe/Kyiv, or auto) and the offset for that date is worked out, summer time included. city is a display label only: nothing here geocodes it, so it never stands in for coordinates. houseSystem is a single Swiss Ephemeris letter, P by default; a name such as \"Placidus\" is refused, and the case matters because I and i are two different Sunshine systems."New value: +"Birth data for a single natal chart. Required: date (YYYY-MM-DD), time (HH:mm:ss), latitude and longitude in decimal degrees. The short forms lat, lon, lng and tz are rejected with 400 INVALID_FIELD; pass the full names. timezoneOffset is hours from UTC and defaults to 0, meaning UTC; send timezone instead (an IANA name such as Europe/Kyiv, or auto) and the offset for that date is worked out, summer time included. city is a display label only: nothing here geocodes it, so it never stands in for coordinates. houseSystem is a single house-system letter, P by default; a name such as \"Placidus\" is refused, and the case matters because I and i are two different Sunshine systems."

Addedv1.6.0Oct 24, 2026

TDQS

B3.2/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds two things the annotations do not: the return payload ('SVG plus illumination metrics') and a cost of 10 credits (Tier 1), which is genuinely useful for agent decision-making. It says nothing about size limits, theme defaults, or format fallback, though those live in the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two front-loaded sentences state purpose and return, followed by a compact metadata block (group, endpoint, cost). Nothing is redundant, though the bracketed metadata is boilerplate rather than tool-specific guidance.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, and annotations cover safety. What remains missing is where this render tool sits relative to the other moon-phase and render tools in a large sibling set, which matters for selection in this catalog.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the nested body schema documents date/time, coordinates, timezone handling, ayanamsa, and house system in detail. The description adds no parameter-level meaning beyond that, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Render the moon disk with its illuminated fraction') plus the trigger condition ('at the given moment'). It also implies the output type ('SVG plus illumination metrics'), which separates it from pure-data siblings like astroway_calendar_moon_phase. It stops short of naming any sibling explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no statement of when to use this tool versus alternatives such as the calendar moon-phase tools or the other render tools. The '[Group: Visualization]' tag hints at the category, but no exclusions, prerequisites, or comparative guidance are given.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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