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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds the radius and category filter behavior but does not disclose potential quirks like API rate limits or response size. It does not contradict annotations, so a mid-range score is fair.

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?

The description is two concise sentences plus a short example call. It front-loads the core action, includes the intended use, and provides a concrete invocation. Every part earns its place with no filler.

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 list tool with 6 well-documented parameters and no output schema, the description gives enough context to invoke correctly: purpose, scope, optional filtering, and an example. It doesn't explain the return format in detail, but 'List what satellites' implies a list of satellite objects, which is reasonable without an output schema. Minor gap but overall sufficient.

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 description coverage is 100%, so all parameters are documented structurally. The description adds examples (e.g., category 52 = Starlink) and an example call, which is helpful but not essential given the schema. It does not introduce meaning beyond the schema, so baseline 3 applies.

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 opens with a specific verb ('List') and a clear resource ('satellites currently above a location on Earth'), and further scopes it by 'within a given radius of the observer's zenith.' This clearly distinguishes it from siblings like get_positions or get_visual_passes. The example call reinforces the purpose.

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?

It explicitly states the intended use case ('Use this to answer "what satellites are overhead right now?"') and shows a concrete example. It does not explicitly list when not to use it or name alternatives, but for a simple query tool, the context is clear enough. A 4 is appropriate for clear context without exclusions.

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