Astro Agents - verifiable planetary timing data and astrology

Kundli (Vedic birth chart)

kundli

Read-onlyIdempotent

Vedic astrology birth chart (kundli, Jyotish horoscope, D1 and D9): lagna and the nine grahas with rashi, nakshatra, pada, house, dignity and combustion. The Jyotish birth chart: ayanamsa (Lahiri default; Raman, KP, Yukteshwar, Fagan-Bradley, True Chitrapaksha), lagna, grahas with rashi, nakshatra/pada/lord, bhava, dignity (exalted, debilitated, moolatrikona, own sign), retrograde and combustion, house table with lords and occupants, and the Navamsa (D9). Deterministic (JPL DE440, no LLM); every result carries meta.result_sha256. Price $0.15 per call via REST POST https://astro-agent.dev/v1/vedic/kundli (x402 or MPP); always paid, never a free call.

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": {
      "latitude": "<latitude>",
      "longitude": "<longitude>"
    },
    "name": "kundli"
  }
}

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 Parashari 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`	Yes	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`	Yes	Decimal degrees, east positive.
`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"
-]

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": {
+        "bhavas": {
+          "description": "The twelve houses (bhavas): sign, rashi, lord and the grahas occupying each one.",
+          "type": "array"
+        },
+        "grahas": {
+          "description": "The nine grahas (Sun to Ketu): sidereal longitude, rashi, sign lord, nakshatra, pada, nakshatra lord, deity, house, and dignity flags.",
+          "type": "array"
+        },
+        "lagna": {
+          "description": "The ascendant (lagna): sidereal longitude, rashi and sign, degree, sign lord, nakshatra, pada and nakshatra lord.",
+          "type": "object"
+        },
+        "settings": {
+          "description": "Settings applied: sidereal zodiac, ayanamsa (name and value in degrees), lunar node type, house system and divisional-chart rules.",
+          "type": "object"
+        },
+        "subject": {
+          "description": "The resolved input: 'time' (local input, time zone and historical UTC offset, UT, Julian days, Delta T) and, when given, 'location' (latitude, longitude).",
+          "type": "object"
+        },
+        "summary": {
+          "description": "Key facts: lagna sign and lord, Moon sign, sidereal Sun sign, janma nakshatra with pada and lord, and the exalted, debilitated, retrograde and combust grahas.",
+          "type": "object"
+        },
+        "vargas": {
+          "description": "Divisional charts D1 (rashi) and D9 (navamsa), keyed by name.",
+          "type": "object"
+        },
+        "warnings": {
+          "description": "Notes on the input or the calculation (for example an assumed noon for an unknown birth time). Present only when there is something to say.",
+          "type": "array"
+        }
+      },
+      "required": [
+        "subject",
+        "settings",
+        "lagna",
+        "grahas",
+        "bhavas",
+        "summary",
+        "vargas"
+      ],
+      "type": "object"
+    }
+  },
+  "required": [
+    "endpoint",
+    "result",
+    "meta"
+  ],
+  "type": "object"
+}

Changed3 schema fields changedOct 5, 2026

addedInput schema / properties / options / description

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

addedInput schema / properties / options / properties / ayanamsa / description

Added value: +"Sidereal reference (ayanamsa). Default 'lahiri' (Chitrapaksha), the Indian standard."

addedInput schema / properties / options / properties / include_outer_planets / description
```
Added value: +"Also return Uranus, Neptune and Pluto (not used in classical Jyotish)."
```

First observedOct 3, 2026

TDQS

B3.4/5.0

Behavior4/5

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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower, and the description still adds real value: determinism (JPL DE440, no LLM), a meta.result_sha256 for verification (which pairs with verify_result_hash), and a mandatory paid call at $0.15 via x402/MPP. It does not cover error behavior or what happens on missing time beyond a brief schema note, which keeps it below 5.

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

Conciseness3/5

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

The output inventory is stated twice in near-identical wording (lagna, grahas, rashi, nakshatra/pada, dignity, house/bhava), which is wasted space. Structure is otherwise decent: identity first, then contents, then determinism/hash, then pricing, but the duplication blunts the front-loading.

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

Completeness4/5

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

With an output schema present and full parameter documentation, the description only needs to supply positioning and operational context, which it largely does (determinism, cost, verification hash). The notable gap is disambiguation from the very similarly named kundli_full and other chart siblings, which is exactly what an agent needs at selection time.

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 every parameter, its enum, and its default is already documented in the schema; baseline 3 applies. The description restates the ayanamsa options and Lahiri default, which largely duplicates schema content rather than adding interpretation such as the effect of house_system choice on bhava output or how time_basis interacts with timezone resolution.

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 states a specific resource (a Vedic/Jyotish D1 + D9 birth chart) with a concrete inventory of outputs: lagna, nine grahas with rashi, nakshatra, pada, house, dignity, combustion, and Navamsa. That is far more specific than a restated title. It does not, however, distinguish itself from sibling tools such as kundli_full, natal_chart, or kp_chart, so an agent cannot tell which chart variant to pick from the description alone.

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 when-to-use guidance at all: nothing explains when to choose this over kundli_full, natal_chart, kp_chart, or vedic_report, nor any prerequisites about birth data accuracy. The only operational guidance given is commercial (paid endpoint, price, payment rails), which helps billing but not tool selection.

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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