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

Annotations already declare readOnlyHint, idempotentHint, and closed-world behavior, so safety is covered. The description adds useful context: the result includes planetary sign, degree, retrograde status, and aspects, and supplying a place adds houses and angles, with a broad valid date range.

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?

Three short sentences, front-loaded with the main purpose and output, followed by optional place and date-range constraints. There is no redundant restatement or wasted text.

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?

For a tool with three optional parameters and no output schema, the description explains what is returned, how place affects the result, and the valid date range. Minor gaps remain around coordinate input format and the exact latitude/longitude pairing semantics.

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?

Only datetime_utc has a schema description, leaving latitude and longitude undocumented at 33% coverage. The description maps 'place' to adding houses/angles and confirms the now-default and date range, but it does not explain coordinate units or whether latitude and longitude should be supplied together.

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 states a specific resource and scope: every planet's position at a moment, including sign, degree, retrograde, and aspects. It distinguishes itself from a single-planet tool by emphasizing 'every planet,' though it does not explicitly name siblings.

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?

It indicates that the moment defaults to now, how to add houses and angles by giving a place, and the supported date range. However, it does not explicitly say when to choose sky_now over natal_chart, transits, or planet_position.

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