Astro Agents - verifiable planetary timing data and astrology

Aspects

aspects

Read-onlyIdempotent

Western astrology aspects: find the aspects between planets at a moment, or between longitudes you supply, with orb, exactness and applying or separating. Either give a moment (datetime, optional place) and get the aspects among all planets, or give 'longitudes' {name: degrees} and get the pure geometry. Orbs are explicit and overridable. With options.declination: declinations and the parallels / contra-parallels too. Deterministic (JPL DE440, no LLM); every result carries meta.result_sha256. Price $0.02 per call via REST POST https://astro-agent.dev/v1/western/aspects (x402 or MPP); each client gets 1 free call on the $0.01-0.02 tools, this one included.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "aspects"
  }
}

Input Schema

Name	Required	Description	Default
`date`	No	YYYY-MM-DD (use with 'time' instead of 'datetime').
`time`	No	HH:MM or HH:MM:SS, 24 h. Omit if unknown (computed at 12:00 with a TIME_UNKNOWN warning).
`options`	No	Optional calculation settings; every default is the common Western convention.
`datetime`	No	Local birth date-time, ISO 8601: '1990-05-15T14:30' (local clock time at the place) or with an explicit offset '1990-05-15T14:30:00+02:00'. Alternative: 'date' + 'time'.
`latitude`	No	Decimal degrees, north positive.
`timezone`	No	IANA zone, e.g. 'Asia/Kolkata'. Optional: resolved from the coordinates, with the historical offset (DST, Local Mean Time) of that date.
`longitude`	No	Decimal degrees, east positive.
`longitudes`	No	Optional {name: degrees} or {name: {longitude, speed, declination?, declination_speed?}}; when given, no ephemeris is used.
`time_basis`	No	What the given clock time is: civil wall-clock (default), UTC, Local Mean Time, or true (apparent) solar time.	civil
`ambiguous_time`	No	Which occurrence to use when a local time happens twice (DST fall-back).	earlier

Output Schema

Name	Required	Description
`meta`	No	Provenance of the result.
`error`	No	x402 offer only: why payment is required.
`result`	No	The calculation result.
`accepts`	No	x402 offer only: the payment options (scheme, network, amount, asset, payTo, ...).
`endpoint`	No	The REST route that computed it, e.g. 'western/natal'.
`resource`	No	x402 offer only: the resource being paid for.
`extensions`	No	x402 offer only: protocol extensions (bazaar).
`x402Version`	No	x402 offer only: protocol version (2).

Schema Changelog

Changes observed during successful MCP inspections.

Changed7 schema fields changedNov 3, 2026

addedOutput schema / anyOf

Added value: +[
+  {
+    "required": [
+      "endpoint",
+      "result",
+      "meta"
+    ]
+  },
+  {
+    "required": [
+      "x402Version",
+      "accepts"
+    ]
+  }
+]

addedOutput schema / properties / accepts

Added value: +{
+  "description": "x402 offer only: the payment options (scheme, network, amount, asset, payTo, ...).",
+  "items": {
+    "type": "object"
+  },
+  "minItems": 1,
+  "type": "array"
+}

addedOutput schema / properties / error

Added value: +{
+  "description": "x402 offer only: why payment is required.",
+  "type": "string"
+}

addedOutput schema / properties / extensions

Added value: +{
+  "description": "x402 offer only: protocol extensions (bazaar).",
+  "type": "object"
+}

addedOutput schema / properties / resource

Added value: +{
+  "description": "x402 offer only: the resource being paid for.",
+  "type": "object"
+}

addedOutput schema / properties / x402Version

Added value: +{
+  "description": "x402 offer only: protocol version (2).",
+  "type": "integer"
+}

removedOutput schema / required

Removed value: -[
-  "endpoint",
-  "result",
-  "meta"
-]

Changed5 schema fields changedOct 29, 2026

changedInput schema / properties / longitudes / description

Previous value: -"Optional {name: degrees} or {name: {longitude, speed}}; when given, no ephemeris is used."New value: +"Optional {name: degrees} or {name: {longitude, speed, declination?, declination_speed?}}; when given, no ephemeris is used."

addedInput schema / properties / options / properties / declination

Added value: +{
+  "default": false,
+  "description": "Also return the declinations and the parallels / contra-parallels between points.",
+  "type": "boolean"
+}

addedInput schema / properties / options / properties / declination_orb

Added value: +{
+  "default": 1,
+  "description": "Orb for parallels and contra-parallels, degrees. Example: 1.",
+  "maximum": 3,
+  "minimum": 0,
+  "type": "number"
+}

addedOutput schema / properties / result / properties / declination_aspects

Added value: +{
+  "description": "With options.declination: parallels and contra-parallels (point_a, point_b, aspect, both declinations, orb, allowed orb, applying or separating).",
+  "type": "array"
+}

addedOutput schema / properties / result / properties / declinations

Added value: +{
+  "description": "With options.declination: the declination of each point, degrees.",
+  "type": "object"
+}

Changed1 schema field changedOct 6, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "endpoint": {
+      "description": "The REST route that computed it, e.g. 'western/natal'.",
+      "type": "string"
+    },
+    "meta": {
+      "description": "Provenance of the result.",
+      "properties": {
+        "astronomy_library": {
+          "description": "Astronomy library and version.",
+          "type": "string"
+        },
+        "compute_ms": {
+          "description": "Computation time in milliseconds.",
+          "type": "number"
+        },
+        "computed_at": {
+          "description": "When it was computed (UTC, ISO 8601).",
+          "type": "string"
+        },
+        "deterministic": {
+          "description": "Always true: same input, same result.",
+          "type": "boolean"
+        },
+        "engine": {
+          "description": "Engine name and version.",
+          "type": "string"
+        },
+        "ephemeris": {
+          "description": "Ephemeris used (NASA/JPL DE440).",
+          "type": "string"
+        },
+        "frame": {
+          "description": "Reference frame of the positions.",
+          "type": "string"
+        },
+        "input_sha256": {
+          "description": "SHA-256 of the canonical input.",
+          "type": "string"
+        },
+        "llm_used": {
+          "description": "Always false: no language model is involved.",
+          "type": "boolean"
+        },
+        "payment": {
+          "description": "How this call was paid: protocol ('free' or 'none'), price and the free calls remaining.",
+          "type": "object"
+        },
+        "reproducibility": {
+          "description": "How to reproduce and check this result.",
+          "type": "string"
+        },
+        "result_sha256": {
+          "description": "SHA-256 of the canonical 'result'; check it with verify_result_hash.",
+          "type": "string"
+        }
+      },
+      "required": [
+        "engine",
+        "deterministic",
+        "llm_used",
+        "input_sha256",
+        "result_sha256"
+      ],
+      "type": "object"
+    },
+    "result": {
+      "description": "The calculation result.",
+      "properties": {
+        "aspects": {
+          "description": "Aspects between two points: point_a, point_b, aspect name, exact angle, orb, allowed orb, exactness percentage and whether it is applying or separating.",
+          "type": "array"
+        },
+        "settings": {
+          "description": "The aspect set and orbs applied, and where the longitudes came from.",
+          "type": "object"
+        }
+      },
+      "required": [
+        "settings",
+        "aspects"
+      ],
+      "type": "object"
+    }
+  },
+  "required": [
+    "endpoint",
+    "result",
+    "meta"
+  ],
+  "type": "object"
+}

Changed4 schema fields changedOct 5, 2026

addedInput schema / properties / options / description

Added value: +"Optional calculation settings; every default is the common Western convention."

addedInput schema / properties / options / properties / house_system / description

Added value: +"House system for cusps and planet houses, e.g. 'placidus' (default) or 'whole_sign'."

addedInput schema / properties / options / properties / luminary_orb_bonus / description

Added value: +"Extra orb in degrees for aspects involving the Sun or the Moon. Example: 2."

addedInput schema / properties / options / properties / zodiac / description

Added value: +"'tropical' (Western, default) or 'sidereal' (pair it with 'ayanamsa')."

First observedOct 3, 2026

TDQS

A4.4/5.0

Behavior5/5

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

With readOnly/idempotent annotations already covering safety, the description still adds substantial context: deterministic JPL DE440 computation, no LLM inference, a per-result meta.result_sha256 for verification, the REST endpoint, $0.02 pricing with x402/MPP payment, and one free call. These are operational facts an agent cannot get from the annotations or 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?

The opening sentence front-loads the two modes, and each subsequent sentence covers one distinct concern: orbs, declinations, determinism, pricing. The pricing/payment sentence is long and packs several ideas together, but every part is operationally relevant rather than filler.

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

Completeness5/5

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. The description still covers both invocation modes, key option behavior, determinism guarantees, and cost/payment, which is sufficient for an agent to decide whether and how to call this 10-parameter tool.

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%, so the baseline is 3. The description confirms that orbs are explicit and overridable and that options.declination adds declinations plus parallels/contra-parallels, which adds modest meaning beyond the schema, but it does not explain longitudes input format or default orb values in more detail than the schema already does.

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

Purpose5/5

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

"Western astrology aspects: find the aspects between planets at a moment, or between longitudes you supply" names a specific verb and resource and immediately states the two input modes. That scope distinguishes it from siblings like synastry or transits, which compute relationships across charts or over time rather than aspect geometry at one moment.

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

Usage Guidelines4/5

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

The description gives an explicit fork: supply a moment (datetime, optional place) for all-planet aspects, or supply 'longitudes' for pure geometry. It also states when declinations apply (options.declination). It does not explicitly say when to prefer this over sibling tools such as synastry or natal_chart, so it stops short of the top score.

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

All Astro Agents - verifiable planetary timing data and astrology tools Inspect

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