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acg_power_lines

Read-onlyIdempotent

Calculate astrocartography power lines (MC, IC, AC, DC) for a birth chart, returning GeoJSON LineStrings for global map rendering and geographic analysis.

Instructions

Calculate Astrocartography power lines (MC, IC, AC/ASC, DC/DSC) for a natal chart. Returns GeoJSON LineStrings tracing each planetary angle line around the globe. These are the latitudinal lines where a planet was rising (AC), setting (DC), culminating (MC), or anti-culminating (IC) at birth.

❌ NOT FOR: 'Is [city] good for me?' or 'What planets affect me in Tokyo?' → For a specific city/location analysis, use acg_hits instead (faster and more relevant). ✅ USE FOR: Getting the full global GeoJSON line geometry for map rendering or bulk geographic analysis.

CREDIT COST: 10 credits per call.

EXAMPLE: Saturn and Jupiter power lines for a chart born 1990-04-15 at 2:30 PM in Chicago: birth_datetime='1990-04-15T14:30:00', timezone='America/Chicago', birth_latitude=41.8781, birth_longitude=-87.6298, bodies=['Saturn', 'Jupiter']

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
bodiesNoList of celestial bodies for line calculation. E.g. ['Sun', 'Moon', 'Venus', 'Mars', 'Jupiter', 'Saturn']. Aliases: 'NorthNode'/'Node'/'Rahu' → MeanNode, 'SouthNode'/'Ketu' → SouthNode. Omit to use all classical planets.
timezoneNoIANA timezone (e.g. `America/Chicago`); required when the datetime is naive, ignored otherwise.
radius_degNoSearch radius in degrees for hits filtering. Default 2°.
birth_datetimeYesISO 8601 datetime; zone required — a `Z`/±HH:MM suffix or the `timezone` argument. Date-only resolves to 12:00 UTC. Full rule: server `instructions`. An unstated zone moves every ACG line by ~15° of longitude per hour.
birth_latitudeYesBirth latitude in decimal degrees. Resolve from a place name with location_search; never recall coordinates from memory.
query_latitudeNoFilter lines near this latitude (optional, for hits mode).
birth_longitudeYesBirth longitude in decimal degrees.
query_longitudeNoFilter lines near this longitude (optional, for hits mode).
Behavior4/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds valuable context: credit cost (10 credits per call), the latitudinal nature of the lines, and the semantic meaning of AC/DC/MC/IC. It doesn't contradict annotations, and the additional details help set expectations for cost and output geometry.

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 well-structured with clear sections: purpose, NOT FOR/USE FOR, credit cost, and example. Every section serves a purpose, and the example is useful. It is front-loaded with the core function and avoids unnecessary 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?

For a tool with 8 parameters and no output schema, the description provides sufficient context: purpose, usage boundaries, credit cost, and a complete example. It also clarifies the nature of the returned GeoJSON lines. No output schema is needed because the return type is stated.

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 description coverage is 100%, so baseline is 3. The description adds a concrete example with sample values for birth_datetime, timezone, coordinates, and bodies, which demonstrates how parameters are combined. This goes slightly beyond the schema's per-field documentation.

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 calculates Astrocartography power lines (MC, IC, AC/ASC, DC/DSC) and returns GeoJSON LineStrings. It uses a specific verb ('Calculate') and resource ('power lines') and distinguishes from the sibling acg_hits by emphasizing global geometry vs. location-specific analysis.

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

Usage Guidelines5/5

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

Explicitly provides both positive ('USE FOR: Getting the full global GeoJSON line geometry...') and negative ('NOT FOR: specific city/location analysis') usage guidance, directly naming the alternative tool acg_hits. This fully clarifies when to use this tool versus alternatives.

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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