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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds that the output includes enter/exact/leave dates, which is meaningful behavioral context beyond the annotations. It does not disclose cost or performance limits, but the annotations carry the main safety burden.

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 core sentence is front-loaded and efficient, with no wasted words. The bracketed metadata lines (Group, Endpoint, Required, Cost) are structured but slightly break the flow, though they add useful routing information.

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 9-parameter tool with only 22% schema description coverage, the description is too thin. It never clarifies default behavior for maxOrb, stepDays, or aspectAngles, nor how the enter/exact/leave dates are formatted. It also omits any mention of pagination or output shape despite having an output schema, which helps but doesn't fully bridge the gap.

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 22%, and the description does not compensate by explaining the semantics of maxOrb, stepDays, aspectAngles, planet1Ids, or planet2Ids. It mentions 'two specific planets,' hinting at the duality of planet arrays, but leaves the orb, step, and aspect-angle parameters completely undocumented in both schema and description.

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 verb and resource: 'Calculate a timeline of when two specific planets form an exact aspect within a date range.' This clearly distinguishes it from siblings like astroway_calendar_aspects (a broader calendar) and astroway_aspects_aspect_bar. It could more explicitly differentiate from those siblings, but the core purpose is unambiguous.

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 implies usage via 'within a date range' and 'two specific planets,' but never states when to choose this tool over siblings like astroway_calendar_aspects or astroway_aspects_aspect_bar. No explicit when-not or alternatives are provided, so the agent must infer.

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