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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so safety is covered. The description adds two useful operational facts beyond the annotations: the cost tier (10 credits, Tier 1) and that one symbol is produced per longitude. It says nothing about output content or limits, hence a middle score.

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 compact sentence front-loads the purpose, followed by short group and cost tags. Nothing is padded, though the bracketed metadata is boilerplate rather than explanatory content.

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?

With an output schema present, return values need not be explained, and annotations cover the safety profile. For a simple per-longitude lookup the description plus structured fields give an agent enough to call it correctly; only usage context is thin.

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 coverage is 67%; the required `longitudes` array has no schema description. The description compensates by specifying these are ecliptic longitudes and that a symbol is returned per element, which is the essential semantic for the undocumented parameter. It still omits units/range detail.

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: returns the Sabian symbol (Dane Rudhyar) for each supplied ecliptic longitude. The resource is unique enough among the astroway_aspects_* siblings that an agent can identify it, but no sibling is named or contrasted, so it falls short of a 5.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives (e.g. other symbol/point lookups). The phrase 'for each given ecliptic longitude' only hints at the input shape, which is already visible in the schema.

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