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

With no annotations provided, the description must carry the transparency burden. It discloses one behavioral trait—titles are discarded—but leaves unstated whether the tool makes a network request, what the return format is, and why the input schema contains nine unrelated optional parameters.

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 short sentences with no filler, and the core purpose is front-loaded before the output constraint. The description is appropriately sized for a simple count operation.

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?

The tool has no annotations and no output schema, and the description does not specify the return type beyond implying a number. It also fails to clarify whether callers should pass any of the nine optional parameters or ignore them entirely, leaving real ambiguity for invocation.

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 100%, so the baseline is 3. The description adds no parameter-level meaning, but each parameter in the schema already states its own behavior, including 'discarded after...' for several. The lack of connection between these parameters and the HN-counting purpose is not explained, though no parameters are required.

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 a specific action ('Count'), a precise target ('current Hacker News front-page stories'), and an output constraint ('Titles discarded'). This clearly differentiates it from fetch/citation siblings that would return content rather than a count.

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 implies when to use it (when HN front-page story count is needed) and hints not to use it for titles, but it does not name alternatives or state explicit when-not conditions. There is no guidance on how it relates to siblings like web-fetch.

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