auseklis

Find Retrograde Periods

find_retrograde_periods

Read-onlyIdempotent

Identify retrograde periods for any planet within a specified date range, returning exact station dates with zodiac positions.

Instructions

Find a planet's retrograde periods in a date range: exact station-retrograde and station-direct moments, with the longitude and sign at each end. Periods overlapping the range edges are included whole.

Examples:

"When is Mercury retrograde in 2026?" -> { body: "Mercury", from_datetime: "2026-01-01", to_datetime: "2027-01-01" }

The Sun and Moon never retrograde and are rejected.

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": {
      "body": "<body>",
      "from_datetime": "<from_datetime>",
      "to_datetime": "<to_datetime>"
    },
    "name": "find_retrograde_periods"
  }
}

Input Schema

Name	Required	Description
`body`	Yes	Which planet (not Sun/Moon).
`to_datetime`	Yes	End of the search window (max 50 years after start).
`from_datetime`	Yes	Start of the search window.

Output Schema

Name	Required	Description	Default
`periods`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.0Jun 10, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Annotations indicate readOnly and idempotent. The description adds behavioral context: inclusive range edges, exact moments, and rejection of Sun/Moon, providing transparency beyond annotations.

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?

The description is concise: 4 sentences and an example, front-loaded with purpose, no fluff.

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 output schema present and clear annotations, the description covers behavior at range edges, rejection cases, and return content, making it complete for an agent.

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

Parameters4/5

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

Schema coverage is 100% with descriptions. The description adds an example showing exact parameter format and clarifies the 'body' rejection of Sun/Moon, which is already in schema, but the example enhances usability.

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?

The description clearly states the tool finds a planet's retrograde periods with specific details (station-retrograde and station-direct moments, longitude, sign). It distinguishes from siblings like find_eclipses or compute_transits by focusing solely on retrograde periods.

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 provides context on when to use (e.g., for retrograde periods) and includes an example and note about Sun/Moon rejection. However, it does not explicitly state when not to use or mention alternative tools, though siblings are listed.

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

Deploy Server