nasa_apod

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

With no annotations provided, the description partially carries the transparency burden. It discloses the output shape (image/video URLs, title, credit, bounded explanation) and notes the sample is 'small,' implying a capped count. However, it omits details like error handling, rate limits, or what happens on invalid input, leaving some behavioral aspects opaque.

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 entire description is one well-structured, front-loaded sentence. It communicates the core purpose, parameters, and return type without extraneous words, making it easy for an agent to quickly parse.

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 (three optional parameters, no output schema), the description covers the main behavior and return contents adequately. It doesn't mention include_hd's purpose or explicitly restate the date/count exclusivity, but the schema already documents the latter. Overall, it is nearly complete for a straightforward read-only API.

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 67% (date and count have descriptions, include_hd does not). The description's phrase 'for a date, or a small random sample' reinforces the date/count parameters but adds no specifics about include_hd or date format. It slightly compensates for the missing include_hd description but does not fully clarify its effect.

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 the tool's function with an explicit verb ('Get') and specific resource ('NASA's Astronomy Picture of the Day'). It also defines the two operating modes (by date or random sample) and the expected return contents, which distinguishes it from sibling NASA tools like search or media asset.

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 for when to use the tool: for a specific date or a random sample. It does not explicitly mention alternatives or exclusions relative to siblings, but the intended use case is evident. The schema also reinforces the mutual exclusivity of date and count, adding to usage clarity.

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