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 mentions 'Titles discarded' but does not disclose whether the tool performs network access, whether it is read-only, what happens on failure, or what the exact return format is. The description is too sparse to convey the tool's behavior beyond the basic count.

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 extremely concise, with only two short sentences. It front-loads the core purpose and adds a clarifying note about titles. There is no wasted wording, making it efficient and easy to scan.

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 that there are 9 optional parameters and no output schema, the description is far from complete. It does not explain what the parameters are for, how to set them, or what the return value looks like. The tool appears to have a simple purpose, but the presence of unrelated parameters creates confusion that the description fails to resolve.

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 description does not mention any of the 9 input parameters, even though they are all optional. The schema descriptions are generic (e.g., 'Git ref name; discarded after the shape check') and seem unrelated to counting HN stories. The description adds no meaning to the parameters, leaving an agent unclear about how to use them or whether they should be omitted entirely.

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 states a specific verb ('Count') and a clear resource ('current Hacker News front-page stories'). It is unambiguous and distinct from sibling tools, which mostly deal with URLs, files, or validation. The added clause 'Titles discarded' further clarifies what is not included.

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 guidance on when to use this tool versus alternatives. It does not mention any exclusion conditions or suggest a preferred tool for related tasks. An agent gets no help in deciding between this and other web-fetching or validation tools.

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