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

With no annotations provided, the description must carry behavioral disclosure. It does state that titles are discarded and that the count is current, which gives some useful behavioral context. However, it does not mention whether the tool performs a live network fetch, what the exact return format is, or how failures are handled.

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 two short sentences with no filler. The core action is front-loaded, and the additional behavioral note earns its place by clarifying output scope.

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, no output schema, and a puzzling 9-parameter optional schema. The description does not explain which parameters, if any, are relevant, whether zero arguments should be passed, or what the returned count looks like. An agent would struggle to invoke it correctly beyond a blind empty call.

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 even without parameter details in the description. The description itself adds no parameter-level meaning, and the 9-parameter schema contains many fields that seem unrelated to counting HN stories, leaving the invocation contract confusing.

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 and resource: 'Count current Hacker News front-page stories.' The additional note 'Titles discarded' clarifies what the tool ignores. It does not explicitly differentiate from siblings, but the action and target are unambiguous.

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?

No guidance is given about when to use this tool versus alternatives like web-fetch or fetch-status, nor are any exclusions or preferred contexts stated. The only implied usage is when a count of HN front-page stories is needed, but that is not made explicit.

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