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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does disclose a real behavioral trait: 'Titles discarded.' It also implies live retrieval via 'current,' but it does not describe the return value shape, failure modes, network behavior, or rate limiting, leaving the disclosure partial.

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 or repetition. The core purpose is front-loaded, and the additional qualifier is separated into a second sentence that 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 tool has nine optional parameters, no output schema, and no annotations, yet the description omits return format and parameter selection guidance. An agent cannot confidently determine whether to pass feed, url, host, or no parameter at all, making the description incomplete for reliable invocation.

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 description does not need to re-explain each parameter. The phrase 'Titles discarded' aligns with the 'feed' parameter's description, providing a mild routing signal. Still, the description never states which of the nine optional parameters is the primary input, leaving some ambiguity for the agent.

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 opens with a specific verb and resource: 'Count current Hacker News front-page stories.' The second sentence, 'Titles discarded,' clarifies an important behavioral boundary. This is enough to distinguish the tool from generic fetching or counting siblings such as web-fetch or memory-key-count.

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 numeric count of current Hacker News front-page stories is needed, and when titles are not needed. However, it does not explicitly name alternatives or state when not to use it, so the guidance remains implicit rather than fully articulated.

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