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

With no annotations, the description carries the behavioral disclosure burden. It does disclose a key behavior: titles are discarded and only a count is relevant. However, it does not explain that the tool ignores its nine input parameters, nor does it mention return format, network dependencies, or failure modes.

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. The core action is front-loaded, and 'Titles discarded' adds a valuable clarification without redundancy. Every word earns its place.

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?

For a simple read-only counter, the description is mostly adequate, but the lack of an output schema means the return shape is unstated. Additionally, the description does not explain why it accepts nine unrelated optional parameters, though the schema's 'discarded' notes partially compensate. An agent can likely call it correctly with no arguments, but these gaps prevent a higher score.

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. Each parameter already has a description, and many explicitly say they are 'discarded after' checks. The tool description adds no parameter-level meaning beyond the phrase 'Titles discarded,' which is about output rather than inputs.

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'), a specific resource ('current Hacker News front-page stories'), and a clear behavioral boundary ('Titles discarded'). This makes the tool's purpose unambiguous and distinguishes it from general fetching or URL-checking sibling tools.

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 gives a clear use case: use this tool when you need the number of current HN front-page stories. 'Titles discarded' implicitly signals that this is not the tool for retrieving story titles, but it does not explicitly name alternatives or provide when-not-to-use conditions beyond that.

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