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

The description carries the full burden because no annotations are provided. It does disclose that titles are discarded, which is a small behavioral hint, but it omits critical details: how the count is returned, whether a network request is made, whether parameters are ignored, and what happens on failure or rate limiting. This is insufficient for a tool with no annotation support.

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 very short and front-loaded with the core action. The second sentence, 'Titles discarded,' is terse but adds a behavioral note. It is not bloated, though the wording could be clearer; no words are wasted.

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 tool with no annotations, no output schema, and 9 optional parameters, the description is too incomplete. It does not specify the return format, whether any parameters are used, how to invoke it correctly, or what side effects or dependencies exist. An agent would be uncertain whether to pass the 'feed' parameter, the 'url' parameter, or nothing at all.

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. The tool description adds little beyond the schema, and it does not clarify which of the 9 optional parameters, if any, are relevant to counting Hacker News stories. The schema descriptions are present but the tool description does not help an agent map parameters to this tool's 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 states a specific action and resource: 'Count current Hacker News front-page stories.' This is clear, precise, and distinct from the sibling tools, which focus on URL checks, time zones, weather hints, and other unrelated operations. The verb 'count' and the bounded resource make the tool's purpose immediately obvious.

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?

There is no guidance about when to use this tool versus alternatives such as web-fetch, fetch-status, or other counting tools. The description gives no context, exclusions, or conditions that would help an agent choose this tool over a sibling. Usage is only implied by the purpose statement.

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