astroway-mcp

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by astroway

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TypeScript

Remote

Group Synastry

astroway_relational_group_synastry

Read-onlyIdempotent

Calculate synastry aspects across 2–8 natal charts at once, returning every pairwise cross-chart aspect matrix for group compatibility analysis.

Instructions

Calculate synastry aspects among 2–8 charts simultaneously, returning all pairwise cross-chart aspect matrices.

[Group: Comparisons] [Endpoint: POST /v1/group-synastry] [Required: inputs] [Cost: 100 credits (Tier 4)]

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": {
      "inputs": "<inputs>"
    },
    "name": "astroway_relational_group_synastry"
  }
}

Input Schema

Name	Required	Description	Default
`inputs`	Yes

Output Schema

Name	Required	Description	Default
`pairs`	No
`charts`	No
`matrix`	No
`averageScore`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.6.1Nov 9, 2026

changedInput schema / properties / inputs / items / 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

B3.4/5.0

Behavior3/5

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

The annotations already cover safety (readOnlyHint=true, destructiveHint=false, idempotentHint=true, openWorldHint=false), so the bar is lower. The description contributes genuinely useful operational context the annotations lack — the POST endpoint and a 100-credit Tier 4 cost — but says nothing about auth, rate limits, or how many pairwise matrices a given input count produces.

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 core sentence is front-loaded and the bracketed metadata block (group, endpoint, required field, cost) is scannable rather than prose. Nearly every line earns its place; the count discrepancy is a correctness issue rather than bloat.

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?

An output schema exists, so return shape need not be described, and the cost/endpoint metadata is a useful addition. However, for a tool whose entire input is one deeply nested array, the description leaves the per-chart requirements and the 8-vs-10 chart count unresolved, and gives no hint about how output volume scales with the number of charts.

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?

Top-level schema coverage is nominally 0%, but the single parameter is an array whose nested item schema carries extensive prose on date/time formats, timezone vs timezoneOffset, ayanamsa, and house-system letter codes, so the schema does the heavy lifting. The description adds only that 'inputs' is required, and it understates the schema: it says 2–8 charts while maxItems is 10, a mismatch an agent could act on incorrectly.

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 ('Calculate synastry aspects among 2–8 charts simultaneously') and adds what comes back ('all pairwise cross-chart aspect matrices'). It does not name the closest sibling (astroway_relational_synastry) as the two-chart alternative, so an agent must infer the distinction from the chart count alone.

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?

The '2–8 charts simultaneously' phrasing implies this is the multi-chart counterpart to pairwise synastry, and '[Required: inputs]' signals the one mandatory argument. There is no explicit when-to-use/when-not-to-use statement, no prerequisite note, and no named alternative, so routing relies on inference.

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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