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

Annotations are absent, so the description carries the full burden. It discloses 'Titles discarded' as one behavioral trait, but omits that the tool likely performs a live network fetch, what the output format is, and whether any of the nine input parameters affect the result. This is a thin disclosure for a tool with no annotation safety profile.

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 core purpose is front-loaded and 'Titles discarded' earns its place by narrowing the expected output. This is appropriately compact for a simple counting tool.

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 nine optional parameters and no output schema, the description is too thin. It does not specify the return type, the live-fetch dependency, or whether the parameters are ignored, leaving an agent uncertain about how to invoke it correctly despite the schema's per-parameter descriptions.

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 description adds no parameter-level meaning beyond the schema, and it does not clarify whether any parameter is used or all are decoys. It neither helps nor hurts 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?

States a specific action ('Count') and resource ('current Hacker News front-page stories'), and clarifies output scope with 'Titles discarded.' This is clear and narrowly scoped, but it does not explicitly differentiate from sibling tools or clarify the role of the many input parameters.

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?

Provides no guidance on when to use this tool versus alternatives like web-fetch, fetch-status, or normalize-url. It also does not say whether the feed parameter is relevant or whether all parameters can be ignored, so an agent has no basis for choosing this over a sibling.

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