ephemeris_house_cusps

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful context beyond annotations: 'CREDIT COST: 1 credit per call' and the full list of house system codes with their meanings, which inform invocation behavior. No contradiction with annotations.

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

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

The description is concise and front-loaded: the first sentence states the core function, followed by a neat code list, credit cost, and a compact example. No extraneous content; every sentence contributes useful operational detail. Minor deduction for being slightly longer than strictly necessary, but structure is clean.

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

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

Given there is no output schema, the description helps by naming the return concepts (ASC, MC, DSC, IC) and offering an example invocation. It also notes the required timezone handling via the schema. It does not describe the output format or edge-case constraints, but the provided details are sufficient for a qualified agent to call the tool correctly.

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

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

Input schema covers all 5 parameters with detailed descriptions, so the schema does most of the heavy lifting. The description adds value by mapping house system codes to names (P=Placidus, K=Koch, etc.) and providing a concrete example that shows how datetime, latitude, longitude, and house_systems combine. This exceeds the baseline for a fully documented schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Description opens with 'Calculate house cusps and angles (ASC, MC, DSC, IC) for a given date, time, and location using one or more house systems.' This is a specific verb+resource, and the explicit list of angles makes the scope unmistakable. It clearly distinguishes from sibling ephemeris tools that target transits, natal charts, or other astrological calculations.

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

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

The description conveys when the tool is relevant (calculating house cusps) and provides an example, but it does not explicitly state when to use this over alternatives or offer any 'when not to use' guidance. Sibling tool names like ephemeris_natal_chart and ephemeris_transits imply alternatives, yet no direct comparison is made.

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