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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real behavioral content — output includes closest and farthest samples, and step count trades off precision — but says nothing about output shape, timestamp granularity, or how many samples are returned.

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?

Two tight sentences with the core purpose front-loaded and the precision caveat second. Nothing is wasted, though the parenthetical '(for a table or a chart)' is slightly weaker than the rest.

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 five-parameter tool with no output schema and partial schema coverage, the description covers what the series contains but not the sample count (steps vs steps+1), the format of from/to, or whether the closest/farthest samples are separate fields or derived. Adequate but with clear gaps.

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 60%: start/end and steps are documented in the schema, from/to are not. The description usefully implies from/to are the two objects and explains the precision effect of steps, but leaves the format of the object identifiers (name, NORAD ID, etc.) entirely unstated.

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 computation: distances between two objects sampled evenly over a period, with closest and farthest samples, and notes the table/chart use case. This implicitly distinguishes it from a single-shot perigee_distance or perigee_close_approach, but never names the sibling it replaces.

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 phrase 'for a table or a chart' implies when the series form is appropriate, and the second sentence gives guidance on choosing steps. However, there is no explicit when-to-use vs perigee_distance / perigee_close_approach routing, which is the sibling decision an agent actually faces.

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