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

With readOnlyHint=true and openWorldHint=true already covering the safety profile, the description adds the returned category set and the filtering semantics of owner/operator/group (code or name). It does not disclose response shape details, how 'recent launches' is bounded in time, or what happens with non-matching filter values.

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 sentences, front-loaded with the core purpose, and the long comma-delimited enumeration is dense but informational rather than padding. Slightly list-heavy, but nothing is redundant.

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?

There is no output schema, so the description must convey what comes back, and it largely does by listing every count category plus the per-category listing behavior implied by 'limit'. Minor gaps remain around result ordering and the time window for 'recent launches'.

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%, with group, owner and operator undocumented in the schema, so the description carries real weight here. It supplies concrete example values for each (US/PRC/CIS/ESA for owner, SpaceX/OneWeb/Amazon Kuiper for operator, constellations/navigation/weather for group) and clarifies that codes or names are accepted.

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 ('Counts of the active satellites') and enumerates the exact breakdown dimensions returned (owner, operator, CelesTrak group, orbit regime, object type, launch year, altitude bands). This makes it unmistakably the aggregation/statistics tool versus siblings like perigee_find or perigee_object, though no sibling is named explicitly.

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?

Usage is only implied: an agent can infer this is the tool for aggregate counts rather than object lookup, and the note that owner/operator/group 'narrow a list' hints at filtering behavior. There is no explicit 'use this instead of X when Y' guidance or stated prerequisites.

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