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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful non-schema context in the cost (10 credits, Tier 1) and the explicit endpoint and required-parameter list, but says nothing about computation scope, what the 'attributions' contain, or any limits. With annotations carrying safety, the added cost line justifies a 3.

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?

It is short and the bracketed block is scannable, so there is no wasted prose. However, the brevity is under-specification rather than economy: the front sentence carries almost no information and the rest is administrative metadata.

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 not be explained, but for a 15-parameter chart tool with only 33% schema coverage the description leaves too much unstated — notably which optional settings matter for a decan chart and how timezone, zodiac type and ayanamsa interact. The definition is not complete enough to invoke confidently without reading the schema in depth.

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 only 33% across 15 parameters, so the description must compensate and does not. It merely repeats the four required parameters (date, time, latitude, longitude) that the schema's required array already enforces, and says nothing about the semantically important undocumented options such as zodiacType, houseSystem, timezone/timezoneOffset, fields, or ayanamsaId.

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?

The description names the resource ('zodiacal decans') and notes it includes 'attributions', but it is essentially a restatement of the title with a qualifier rather than a distinct verb+resource statement. It offers no differentiation from the very close sibling astroway_helg_zodiacal_decans (or the related decan/dodekatemoria siblings), so an agent cannot tell why this Greenbaum version exists alongside them.

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 only operational guidance is bracketed metadata: required inputs, endpoint, and cost tier. There is no statement of when to reach for decans, when to prefer a sibling traditon (e.g. helg_zodiacal_decans or dodekatemoria), or what a decan computation is appropriate for. The agent must infer usage entirely.

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