iss

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

No annotations are provided, so the description carries the full burden. It discloses one behavioral trait, that the data reflects the present moment ('Current'), which tells the agent results are time-sensitive, but it says nothing about update frequency, rate limits, or response format.

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?

A single front-loaded sentence with no filler. Every word earns its place and the key noun (International Space Station) and payload (position and altitude) come first.

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 no output schema, the description must signal what comes back, and it does so by naming position and altitude. It stops short of describing the coordinate format or units, which is a minor gap for a zero-parameter read tool.

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 tool takes zero parameters, so per the baseline rule this scores 4. The description correctly adds no parameter detail, which is appropriate for a parameterless call.

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 names the resource (International Space Station) and the exact data returned (current position and altitude), which is far more informative than the opaque name 'iss'. It does not differentiate from siblings, but the sibling set (base_fee, earthquakes, weather, postcard) is so disjoint that no differentiation is needed.

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?

There is no explicit when-to-use or when-not-to-use guidance, but the tool's purpose is unambiguous and there are no competing siblings that could be confused with it, so usage is implied. The word 'Current' hints at time-sensitivity but no guidance is given about refresh or staleness.

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