astroway-mcp

Official

by astroway

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TypeScript

Remote

Composite Chart (SVG)

astroway_render_composite

Read-onlyIdempotent

Render a midpoint composite chart wheel as SVG or JSON from two natal birth charts. Use it to visualize a relationship's composite astrology in a Western wheel.

Instructions

Composite-chart wheel from two natal inputs. Computes midpoint composite then renders as Western wheel.

[Group: Visualization] [Endpoint: POST /v1/render/composite] [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_composite"
  }
}

Input Schema

Name	Required	Description	Default
`body`	Yes	Pair of natal charts for relationship calculations: synastry, composite, davison.

Output Schema

Name	Required	Description	Default
`svg`	No
`format`	No
`byteLength`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.6.1Nov 9, 2026

changedInput schema / properties / body / allOf

Previous value: -[
-  {
-    "description": "Pair of natal charts for relationship calculations: synastry, composite, davison.",
-    "properties": {
-      "chart1": {
-        "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"
-      },
-      "chart2": {
-        "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"
-      }
-    },
-    "required": [
-      "chart1",
-      "chart2"
-    ],
-    "type": "object"
-  },
-  {
-    "properties": {
-      "options": {
-        "properties": {
-          "bodies": {
-            "items": {
-              "enum": [
-                "Sun",
-                "Moon",
-                "Mercury",
-                "Venus",
-                "Mars",
-                "Jupiter",
-                "Saturn",
-                "Uranus",
-                "Neptune",
-                "Pluto",
-                "North Node",
-                "South Node",
-                "Chiron",
-                "Lilith"
-              ],
-              "type": "string"
-            },
-            "maxItems": 14,
-            "minItems": 1,
-            "type": "array"
-          },
-          "format": {
-            "default": "json",
-            "enum": [
-              "svg",
-              "json"
-            ],
-            "type": "string"
-          },
-          "labels": {
-            "additionalProperties": false,
-            "description": "Your own words in place of the English the image would otherwise carry: the ASC/DSC/MC/IC axis labels, the SVG <title> and <desc> read by screen readers, and the planet and sign names plus the word for retrograde in each planet's data-label (theme css). bodies is keyed by the English name, signs lists twelve names from Aries. Nothing is translated for you; absent keys keep the English.",
-            "properties": {
-              "asc": {
-                "maxLength": 40,
-                "minLength": 1,
-                "type": "string"
-              },
-              "bodies": {
-                "properties": {
-                  "Chiron": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Jupiter": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Lilith": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Mars": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Mercury": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Moon": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Neptune": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "North Node": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Pluto": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Saturn": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "South Node": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Sun": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Uranus": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  },
-                  "Venus": {
-                    "maxLength": 40,
-                    "minLength": 1,
-                    "type": "string"
-                  }
-                },
-                "type": "object"
-              },
-              "desc": {
-                "maxLength": 2000,
-                "minLength": 1,
-                "type": "string"
-              },
-              "dsc": {
-                "maxLength": 40,
-                "minLength": 1,
-                "type": "string"
-              },
-              "ic": {
-                "maxLength": 40,
-                "minLength": 1,
-                "type": "string"
-              },
-              "mc": {
-                "maxLength": 40,
-                "minLength": 1,
-                "type": "string"
-              },
-              "retrograde": {
-                "maxLength": 40,
-                "minLength": 1,
-                "type": "string"
-              },
-              "signs": {
-                "items": {
-                  "maxLength": 40,
-                  "minLength": 1,
-                  "type": "string"
-                },
-                "type": "array"
-              },
-              "title": {
-                "maxLength": 200,
-                "minLength": 1,
-                "type": "string"
-              }
-            },
-            "type": "object"
-          },
-          "showAspects": {
-            "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: +[
+  {
+    "description": "Pair of natal charts for relationship calculations: synastry, composite, davison.",
+    "properties": {
+      "chart1": {
+        "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"
+      },
+      "chart2": {
+        "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"
+      }
+    },
+    "required": [
+      "chart1",
+      "chart2"
+    ],
+    "type": "object"
+  },
+  {
+    "properties": {
+      "options": {
+        "properties": {
+          "bodies": {
+            "items": {
+              "enum": [
+                "Sun",
+                "Moon",
+                "Mercury",
+                "Venus",
+                "Mars",
+                "Jupiter",
+                "Saturn",
+                "Uranus",
+                "Neptune",
+                "Pluto",
+                "North Node",
+                "South Node",
+                "Chiron",
+                "Lilith"
+              ],
+              "type": "string"
+            },
+            "maxItems": 14,
+            "minItems": 1,
+            "type": "array"
+          },
+          "format": {
+            "default": "json",
+            "enum": [
+              "svg",
+              "json"
+            ],
+            "type": "string"
+          },
+          "labels": {
+            "additionalProperties": false,
+            "description": "Your own words in place of the English the image would otherwise carry: the ASC/DSC/MC/IC axis labels, the SVG <title> and <desc> read by screen readers, and the planet and sign names plus the word for retrograde in each planet's data-label (theme css). bodies is keyed by the English name, signs lists twelve names from Aries. Nothing is translated for you; absent keys keep the English.",
+            "properties": {
+              "asc": {
+                "maxLength": 40,
+                "minLength": 1,
+                "type": "string"
+              },
+              "bodies": {
+                "properties": {
+                  "Chiron": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Jupiter": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Lilith": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Mars": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Mercury": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Moon": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Neptune": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "North Node": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Pluto": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Saturn": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "South Node": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Sun": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Uranus": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  },
+                  "Venus": {
+                    "maxLength": 40,
+                    "minLength": 1,
+                    "type": "string"
+                  }
+                },
+                "type": "object"
+              },
+              "desc": {
+                "maxLength": 2000,
+                "minLength": 1,
+                "type": "string"
+              },
+              "dsc": {
+                "maxLength": 40,
+                "minLength": 1,
+                "type": "string"
+              },
+              "ic": {
+                "maxLength": 40,
+                "minLength": 1,
+                "type": "string"
+              },
+              "mc": {
+                "maxLength": 40,
+                "minLength": 1,
+                "type": "string"
+              },
+              "retrograde": {
+                "maxLength": 40,
+                "minLength": 1,
+                "type": "string"
+              },
+              "signs": {
+                "items": {
+                  "maxLength": 40,
+                  "minLength": 1,
+                  "type": "string"
+                },
+                "type": "array"
+              },
+              "title": {
+                "maxLength": 200,
+                "minLength": 1,
+                "type": "string"
+              }
+            },
+            "type": "object"
+          },
+          "showAspects": {
+            "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"
+  }
+]

Addedv1.6.0Oct 24, 2026

TDQS

B3.4/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is fully covered. The description adds genuinely useful operational context the annotations lack: the POST endpoint and the 10-credit Tier 1 cost, which lets an agent reason about spend before calling. It says nothing about the compute/render split in terms of latency, caching, or what happens with mismatched inputs, so it lands at adequate rather than rich.

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 the computation and the output, and the bracketed group/endpoint/cost lines are compact and scannable. Nothing is redundant, though the metadata block is boilerplate that could be trimmed if the platform exposes endpoint and cost elsewhere.

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?

With an output schema present, the description needn't explain return values, and the input schema is exhaustive, so the essential contract is covered. However, the tool is titled and described as an SVG wheel while the options schema defaults format to json, a notable default the description never mentions, and there is no indication of what the two-chart pairing rejects (for example, mismatched zodiac or house-system settings).

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%, with both nested birth-data objects and the options block documented in detail, so the schema carries the parameter burden. The description adds only the phrase 'midpoint composite', which clarifies how the two inputs are combined, but gives no guidance on the options payload (size, theme, format, labels) that a caller must navigate.

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 pair: computes the midpoint composite of two natal charts and renders it as a Western wheel. An agent can tell this apart from a plain wheel renderer because the two-chart input requirement is explicit. It does not, however, distinguish itself from the related relational/composite sibling tool, so it stops short of a 5.

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

Usage Guidelines3/5

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

Usage is only implied: 'from two natal inputs' tells the agent it needs two birth-chart objects, but there is no stated when-to-use versus when-not, and no routing to alternatives such as the relational composite or the single-chart Western wheel renderer. The agent must infer selection from the name and purpose sentence alone.

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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