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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds genuinely new behavioral context beyond that: retrograde re-entries are included in the result set, and the call costs 100 credits (Tier 4), which is operationally relevant for an agent budgeting calls.

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 tight sentence front-loads the core behavior, followed by short structured group/cost tags. Nothing is wasted, though the bracketed metadata is boilerplate rather than informative prose.

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 no explanation. For a 5-parameter tool the description covers the essential inputs, the retrograde nuance, and cost, but omits any routing guidance among the many calendar siblings and says nothing about the compact-mode options, leaving a modest 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 coverage is only 40%: planetId, startDate, and endDate have no schema descriptions, and the description compensates by naming the planet and date range as the operative inputs. It says nothing about the two optional compact-mode parameters (fields, precision), though those are already documented in the schema, so the net compensation is adequate but not deep.

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 gives a specific verb and resource ('Find all sign ingresses for a planet within a date range') and adds a scope qualifier ('including retrograde re-entries') that clarifies the semantics of 'ingress'. It does not, however, distinguish itself from close siblings such as astroway_calendar_retrograde_periods or astroway_calendar_planetary_cycles, so an agent must infer the boundary.

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 or when-not-to-use guidance and no named alternative. The agent is left to infer from the date-range/planet framing that this is a time-window scan, with nothing steering it away from overlapping tools like retrograde_periods or planetary_cycles.

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