jpl_close_approaches

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

The readOnlyHint annotation already establishes safety, and the description adds valuable context beyond that: the unit conversion (1 AU ≈ 150M km) and an example invocation. It does not contradict annotations and helps the agent understand the meaning of distance values. It could mention response format or pagination, but the description is still informative.

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 compact: three sentences that front-load the core purpose, then provide necessary unit context and an example. Every sentence serves a purpose. It is neither verbose nor under-specified.

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?

Given the tool's simplicity and the presence of a detailed schema, the description covers the essential details: what it does, how to filter, units, and an example. It does not state the return type, but 'close approaches' implies a list. For a read-only query tool, this is sufficient, though a note on the output format could make it fully complete.

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?

The input schema has 100% description coverage, so parameters are already well-documented. The description adds a concrete example showing the combined use of date_min, date_max, and dist_max, which helps clarify parameter interaction. The unit conversion is also reinforced, though partially redundant with the schema. This adds practical value beyond the schema.

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+resource: 'Get asteroid/comet close approaches to Earth.' This clearly differentiates from sibling tools like jpl_small_body or jpl_fireball. It states the exact subject and action, leaving no ambiguity about what the tool does.

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 provides clear context: filtering by date range, distance, and result limit. It does not explicitly mention alternatives or when not to use the tool, but the context is unambiguous. The example usage further clarifies how to combine parameters, giving an implicit 'how to use' guide.

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