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

The annotations already declare readOnlyHint and openWorldHint, so safety is covered; the description adds real value by disclosing the full return payload (sources and verification date, image credit/licence, Perigee view links) in the absence of an output schema. It also explains that include_image changes the response to embed the image, which hints at a larger payload, but it omits what happens for an unknown id and any rate-limit or error behaviour.

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 with the purpose, then a dense but useful enumeration of returned fields, plus one short sentence on include_image. The long field list is justified because no output schema exists, though it could be trimmed slightly.

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 read-only lookup with no output schema, documenting the return fields is the right move and largely done. However, with three parameters at 33% schema coverage and a crowded sibling set, the description leaves gaps on id format, failure modes, and how it relates to perigee_find or perigee_describe_view.

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 33%: only 'lang' is documented, while the required 'id' has merely min/max length and 'include_image' is bare. The description rescues include_image ('also returns the image itself') but never explains what form an id takes (NORAD number, COSPAR ID, or Perigee slug), which is the single most consequential ambiguity for a required parameter.

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 makes clear this is a catalogue-metadata lookup for a single object, and the enumerated field list (agency, country, launch date, NORAD/COSPAR/Horizons identifiers, sources, image) sharpens that. It does not state a verb explicitly ('Facts about an object') and never distinguishes itself from siblings like perigee_find, perigee_orbit or perigee_describe_view, 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, when-not-to-use, or prerequisite guidance at all. With 19 siblings including perigee_find and perigee_orbit, the description gives no routing signal for when an agent should fetch static facts versus query find/orbit/state.

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