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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering safety and idempotency. The description adds that it uses the SGP4 algorithm and explains the night_only filter's effect. This adds some behavioral context beyond annotations but does not cover rate limits, authentication, or what 'bright' means. Value is modest.

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 concise sentences (17 words) frontload the core purpose. No redundant or filler content. Every clause adds value. Ideal length for quick scanning.

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?

With 7 parameters, output schema present, and annotations available, the description adequately covers the basic purpose and a key parameter. However, it lacks usage context (e.g., typical scenario, how results relate to output schema) and does not help an agent choose between this and sibling tools like starlink_trains. It is minimally complete for a simple tool but has notable 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 description coverage is only 43% (3 of 7 parameters described in schema: lat, lng, lon). The description explains the night_only parameter's effect, adding meaning for one more parameter. However, lang, limit, and include_tle remain undocumented in both schema and description. The compensation is partial.

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 clearly states it provides 'upcoming bright satellite/ISS passes' and mentions the SGP4 algorithm. The verb 'upcoming' plus resource 'satellite/ISS passes' is specific. However, it does not explicitly differentiate from sibling tools like 'starlink_trains' or 'object_lookup', though the topic is distinct enough.

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 description gives no guidance on when to use this tool versus alternatives. It does not mention prerequisites (e.g., requiring a date/time), nor does it state when night_only should be set to true in a broader recommendation. Sibling tools exist but no comparisons are made.

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