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

With no annotations, the description bears the full burden of disclosing behavior. It only states the action and a cryptic note about titles, but does not mention that the tool likely makes a network request, returns a numeric count, or has any rate limits or side effects. The lack of behavioral detail is a significant gap.

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 concise at two short sentences, front-loading the main action. However, the second sentence 'Titles discarded' is cryptic and does not add clear value. Still, for a simple tool, the brevity is acceptable; it is not padded with filler.

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 is severely incomplete. It does not specify the return value or output format, which is especially important since there is no output schema. It also fails to explain how the optional parameters affect the behavior. Given the tool has nine optional parameters and no required ones, the description gives the agent almost no basis to invoke it correctly.

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 input schema fully documents each parameter (100% coverage), the description adds no meaning about how these nine parameters relate to the count operation. The parameters seem unrelated to counting HN stories (e.g., city, zone, query), and the description does not clarify their purpose or whether any are used. This creates confusion rather than helping.

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 clearly states the tool counts current Hacker News front-page stories, specifying the verb 'Count' and the resource 'Hacker News front-page'. The phrase 'Titles discarded' adds a subtle detail that differentiates it from tools that might return titles, and it is distinct from the sibling tools which focus on URLs, shapes, or validation.

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 provides no guidance on when to use this tool versus alternatives, nor any exclusions or prerequisites. It does not mention any context in which this tool is preferred over, say, web-fetch or fetch-status. The agent is left without clues about selection criteria.

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