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

No annotations exist, so the description carries the full burden of disclosing behavior. It only says 'Titles discarded,' which is opaque; it does not reveal that the tool likely fetches HN data, what network access is needed, whether the count is cached, or what the output format is. The description contradicts its own purpose by implying the parameters are discarded, yet the tool's name suggests a counting operation.

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 extremely concise (one sentence) but this is under-specification rather than effective conciseness. It front-loads the main action but omits essential context, making it unsuitable for agent use.

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?

With 9 parameters, no output schema, and no annotations, the description is grossly incomplete. It fails to explain the tool's actual functionality, how parameters affect the result, what the output represents, or any constraints. An agent has no way to invoke this tool correctly based on the description alone.

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?

Although the schema provides 100% coverage with descriptions for each parameter, the tool description adds no meaning about how these parameters relate to counting Hacker News stories. The parameters are generic (ref, url, city, etc.) and appear irrelevant; the description does not explain why they are accepted or what role they play, leaving the agent unable to determine correct values.

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') and resource ('Hacker News front-page stories'), but the phrase 'Titles discarded' is cryptic and the nine parameters (ref, url, city, feed, host, json, path, zone, query) are entirely unrelated to Hacker News, making the actual purpose ambiguous. It does not differentiate from siblings beyond the unique name, and the description leaves doubt about what the tool actually counts or why these parameters exist.

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?

No guidance is provided on when to use this tool versus any of the 28 siblings. There is no mention of context, prerequisites, or alternatives, leaving an agent without any decision support.

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