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

There are no annotations, so the description must carry the behavioral burden. It does disclose that the count is for the current front page and that titles are discarded, which hints at a read-only, count-only mode. It does not disclose error behavior, external-network assumptions, or whether optional inputs are ignored.

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, each earning its place: the first says what the tool does, the second states an important negative behavior. There is no filler or repetition of the schema.

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 count tool, the description is serviceable: an agent can safely call it with no parameters and expect a count. However, the lack of an output schema and annotations leaves the return format and the effect of the optional generic parameters barely inferred rather than explicitly clear.

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 though the tool description adds little parameter-specific guidance. The nine optional parameters are all documented in the schema, but the description does not clarify how they relate to counting Hacker News stories; 'titles discarded' is the only link to behavior.

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 clearly names a specific action and resource: count current Hacker News front-page stories. It also adds a differentiating behavior by saying titles are discarded. It does not explicitly name sibling tools or contrast with them, so it just misses the bar for a 5.

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 phrase 'titles discarded' implicitly tells the agent this is for count-only results, not for retrieving story content. However, it does not explicitly say when to prefer this over, for example, web-fetch, or provide any when-not/alternative guidance.

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