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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds genuinely new context: the 50-credit Tier 3 cost and the Calendar & Cycles grouping, both useful for selection. It says nothing about output shape or the meaning of 'stations' beyond the three states, but the output schema covers returns.

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?

Front-loaded single sentence followed by compact metadata lines for group and cost; nothing is bloated. It is efficient, though slightly terse given the parameter set it must cover.

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?

Output schema and annotations cover return values and safety, so the burden is reduced. What is missing is how to specify planetIds (opaque integer IDs with no description or enum) and no guidance for the date range, leaving an agent unsure how to construct a valid call for anything but default planets.

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 only 40%; planetIds and the two date params carry no schema descriptions. The description partially compensates by naming the planet concept and the date-range bound, mapping loosely to planetIds/startDate/endDate. It adds nothing about precision or fields, and gives no hint on planet ID enumeration.

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: finding retrograde stations (direct/retrograde/stationary) for a planet over a date range. The scope is clear enough to distinguish from most siblings, but it never differentiates itself from near-neighbors like astroway_calendar_planetary_cycles or astroway_calendar_ingresses, which also return timed station/transition events.

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?

No when-to-use guidance, no mention of alternatives, no prerequisites. The description implies you supply a planet and a date range but never says when this tool is preferable to the other calendar tools that surface retrograde-adjacent events.

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