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

No annotations are provided, so the description carries the transparency burden. It discloses that titles are discarded and that the count is 'current,' but it does not mention network behavior, caching, error cases, or whether any side effects occur. This is adequate but minimal for a simple read-only count tool.

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 main action is front-loaded, and the 'Titles discarded' note is a useful, concise qualifier.

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 counting tool, the description conveys the main purpose and output scope. However, with no output schema and no annotations, it does not explicitly describe the return value format, failure behavior, or the role of the many optional parameters, so an agent still has minor gaps to bridge.

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 input schema has 100% description coverage for all nine parameters, so the description need not restate them. However, the description does not clarify whether any of these optional parameters actually affect the HN count or are irrelevant, leaving some ambiguity about invocation.

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 clarifies output scope with 'Titles discarded.' This is immediately distinguishable from the sibling fetch, status, and shape-check 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 implies when to use the tool: when a count of current HN front-page stories is needed. It does not explicitly name alternatives or state when not to use it, but the context is reasonably clear from the wording.

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