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 limitation ('Titles discarded') and implies a read-only counting operation. However, it does not explain whether external fetches occur, what the output format is, or why all nine parameters are accepted, leaving several behavioral aspects opaque.

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 primary action is front-loaded, and the second sentence adds a meaningful constraint. 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?

The description identifies the tool's core purpose but does not clarify how the nine optional, seemingly unrelated parameters relate to the operation. There is no output schema, no annotation coverage, and no statement that the parameters are discarded, so an agent cannot confidently determine which arguments, if any, should be supplied. This is a meaningful gap for a tool with this much schema surface area.

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, so the baseline is 3 even though the tool description itself explains no parameters. The only relevant parameter clarification, 'Titles discarded,' is also present in the feed parameter description. The description therefore adds little beyond what the schema already provides.

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 clear, specific action: 'Count current Hacker News front-page stories.' It also adds an important scoping detail with 'Titles discarded,' so an agent immediately knows the output is a count rather than story content. This is sufficiently distinct from the listed 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 implies when to use this tool: whenever the current number of Hacker News front-page stories is needed. 'Titles discarded' hints that it should not be used when titles are required, but the description does not name alternatives or provide explicit when-not-to-use guidance.

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