astroway-mcp

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by astroway

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TypeScript

Remote

Synastry Aspect Grid

astroway_relational_synastry_aspect_grid

Read-onlyIdempotent

Build an NxM cross-chart aspect grid between two birth charts to compare synastry contacts planet by planet, with each cell showing the aspect or null.

Instructions

NxM matrix of cross-chart aspects between the two charts (default 13×13: Sun..Pluto + nodes + Lilith + Chiron). Cells contain aspect or null.

[Group: Comparisons] [Endpoint: POST /v1/synastry/aspect-grid] [Required: chart1, chart2] [Cost: 50 credits (Tier 3)]

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": {
      "chart1": "<chart1>",
      "chart2": "<chart2>"
    },
    "name": "astroway_relational_synastry_aspect_grid"
  }
}

Input Schema

Name	Required	Description	Default
`chart1`	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.
`chart2`	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
`grid`	No
`totals`	No
`bodies1`	No
`bodies2`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv1.6.1Nov 9, 2026

changedInput schema / properties / chart1 / 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."

changedInput schema / properties / chart2 / 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

A3.6/5.0

Behavior4/5

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's job is to add what they don't: it discloses the credit cost (50 credits, Tier 3), the HTTP endpoint, and the fixed default matrix size with null cells for non-aspecting pairs. Those are real behavioral facts an agent can plan around, and nothing contradicts the annotations.

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 substantive definition is a single dense sentence front-loaded with the matrix shape and default contents, followed by compact bracketed metadata for group, endpoint, required fields and cost. Nothing is repeated, though the bracketed block is a little mechanical.

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?

With an output schema present the description need not describe return values, and with 100% schema coverage the two nested chart parameters are self-documenting. Against that backdrop the description supplies the remaining pieces an agent needs — matrix dimensions, null-cell semantics, required inputs, and cost tier — so nothing material is missing.

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%: chart1 and chart2 are fully documented nested birth-data objects, including timezone and houseSystem caveats. The description only restates that both are required, which the schema already declares, so no meaning is added beyond the structured fields — baseline 3 is appropriate.

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 names a specific artifact — an NxM cross-chart aspect matrix between two charts — and specifies the default extent (13×13: Sun..Pluto + nodes + Lilith + Chiron) and cell payload (aspect or null). That is far more concrete than a generic 'synastry' label, though it never names a sibling such as astroway_render_aspect_grid to disambiguate data-vs-rendering.

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 statement and no exclusion. An agent comparing this against astroway_relational_synastry or astroway_render_aspect_grid gets no criteria in the description for choosing; it must infer from the name and nearby tools.

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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