Cyclic Index

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

Annotations already establish readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered. The description adds genuinely non-structured operational context: the endpoint, the required inputs, and notably a cost of 100 credits (Tier 4), which an agent needs for budget decisions. Response shape is left to the output schema.

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?

One dense sentence front-loads the definition and purpose, followed by a compact metadata block (group, endpoint, required params, cost) with no filler. Nothing is padded, though the metadata block is somewhat boilerplate relative to the single sentence of prose.

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?

An output schema exists, so return values need no explanation, and the tool is conceptually simple (year range in, index out). Still missing: the temporal granularity of the output (annual vs. finer), the scale/units of the index, and any meaning for the 'pairs' input — gaps that matter for correct invocation.

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?

Schema description coverage is 0%, so the description must carry the load. It explains startYear/endYear implicitly via 'date range' and explicitly names them as required, but the third parameter 'pairs' (an untyped anyOf with an empty schema) is completely opaque in both schema and description — an agent cannot know what to pass or whether to omit it.

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?

States a specific verb and resource ('Calculate the André Barbault Cyclic Index') and adds a precise definition ('sum of all outer planet separations') plus the interpretive purpose ('indicate global crisis periods'). It does not name a sibling alternative (e.g. astroway_calendar_planetary_cycles), so it falls short of the top mark, but the tool is easy to tell apart from the surrounding Calendar & Cycles tools.

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 phrase 'for a date range to indicate global crisis periods' implies the use case, and the metadata block flags startYear/endYear as required. However, it never says when to choose this over neighbouring cycle tools or what conditions make it inappropriate (e.g. long ranges, granularity limits).

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