AstroWay Astrology API (full catalogue)

HD Design Date

astroway_hd_design_date

Read-onlyIdempotent

Find the Design date (the moment 88° of solar arc before birth) for a given birth moment, the unconscious imprinting point.

[Group: Human Design] [Endpoint: POST /v1/hd/design-date] [Required: date, time, latitude, longitude] [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": {
      "date": "<date>",
      "time": "<time>",
      "latitude": "<latitude>",
      "longitude": "<longitude>"
    },
    "name": "astroway_hd_design_date"
  }
}

Input Schema

Name	Required	Description	Default
`city`	No
`date`	Yes
`name`	No
`time`	Yes
`fields`	No	Compact mode: comma-separated dotted paths to keep, relative to `data`, e.g. "planets.name,planets.longitude,houses.cusp". Omit for the whole response.
`ayanamsa`	No	Sidereal school by name. Lahiri when omitted. Equivalent to ayanamsaId; send either.
`latitude`	Yes
`timezone`	No	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.
`cosmogram`	No
`longitude`	Yes
`precision`	No	Compact mode: round fractional numbers to this many decimals. Longitudes carry 14 by default; 2 is finer than any chart is drawn.
`ayanamsaId`	No
`zodiacType`	No
`houseSystem`	No		P
`timezoneOffset`	No	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.

Output Schema

Name	Required	Description	Default
`birthJd`	No
`designJd`	No
`designDate`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed7 schema fields changedNov 7, 2026

removedInput schema / properties / ayanamsaId / anyOf

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

addedInput schema / properties / ayanamsaId / type
```
Added value: +[
+  "number",
+  "null"
+]
```

removedOutput schema / properties / birthJd / anyOf

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / birthJd / type
```
Added value: +[
+  "number",
+  "null"
+]
```

changedOutput schema / properties / designDate / anyOf

Previous value: -[
-  {
-    "additionalProperties": {},
-    "properties": {
-      "day": {
-        "anyOf": [
-          {
-            "type": "number"
-          },
-          {
-            "type": "null"
-          }
-        ]
-      },
-      "hour": {
-        "anyOf": [
-          {
-            "type": "number"
-          },
-          {
-            "type": "null"
-          }
-        ]
-      },
-      "month": {
-        "anyOf": [
-          {
-            "type": "number"
-          },
-          {
-            "type": "null"
-          }
-        ]
-      },
-      "year": {
-        "anyOf": [
-          {
-            "type": "number"
-          },
-          {
-            "type": "null"
-          }
-        ]
-      }
-    },
-    "type": "object"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "additionalProperties": {},
+    "properties": {
+      "day": {
+        "type": [
+          "number",
+          "null"
+        ]
+      },
+      "hour": {
+        "type": [
+          "number",
+          "null"
+        ]
+      },
+      "month": {
+        "type": [
+          "number",
+          "null"
+        ]
+      },
+      "year": {
+        "type": [
+          "number",
+          "null"
+        ]
+      }
+    },
+    "type": "object"
+  },
+  {
+    "type": "null"
+  }
+]

removedOutput schema / properties / designJd / anyOf

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / designJd / type
```
Added value: +[
+  "number",
+  "null"
+]
```

First observedOct 5, 2026

TDQS

A3.5/5.0

Behavior4/5

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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the bar is lower, and the description still adds real context: it is a 10-credit Tier 1 call, it hits POST /v1/hd/design-date, and it names the required inputs. It does not disclose defaulting behavior (Lahiri ayanamsa, timezoneOffset 0, timezone overriding offset), which matters for reproducibility of a computed moment.

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

Conciseness5/5

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

One definitional sentence up front, then compact bracketed metadata lines for group, endpoint, required inputs, and cost. No filler, and the most decision-relevant content (what the date is) leads.

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?

Return values need not be explained because an output schema exists, and safety is covered by annotations. However, for a 15-parameter computation the description leaves the role of the optional chart parameters and time-basis defaults unaddressed, which is a meaningful gap for a 10-credit call that must be reproducible.

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

Parameters2/5

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

Schema description coverage is only 33% across 15 parameters, so the description must carry weight, yet it only restates the four required fields the schema already marks as required. Unexplained parameters such as zodiacType, houseSystem, cosmogram, ayanamsaId, and whether city/name affect the computation are left opaque, and an agent cannot tell which optional chart-shaping knobs actually change a Design date.

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?

The description gives a specific verb plus a precisely defined astronomical quantity: 'Find the Design date (the moment 88° of solar arc before birth) for a given birth moment.' That definition alone lets an agent distinguish this from siblings like astroway_hd_human_design or astroway_hd_incarnation_cross, but no sibling is named to route the agent explicitly.

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: an agent infers the tool is needed when a Design date is required. There is no statement of when to prefer this over the full chart tools, no prerequisite such as 'use the result as input to the Human Design bodygraph call', and no exclusion criteria.

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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