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

With no annotations, the description carries the full burden of behavioral disclosure. It only says the tool counts stories and discards titles, but does not explain side effects, network usage, parameter handling, or return format. It also does not clarify that the tool performs only local shape validation (as implied by the schema) rather than live fetching. This is a significant gap for a tool with 9 optional parameters.

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 a single sentence, so it is concise, but it is under-specified. It front-loads the main purpose but omits critical details such as input expectations and return value. The brevity is not balanced with completeness, making it less effective than a slightly longer but more informative description.

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?

Given the tool has 9 optional parameters, no output schema, and no annotations, the description is extremely incomplete. It does not explain what the tool returns (e.g., a number), what the parameters are for, or whether it performs any network calls. The agent cannot reliably invoke this tool based on the provided information, especially because the parameters seem unrelated to the stated purpose.

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?

The schema provides 100% coverage with each parameter described (e.g., 'discarded after the shape check'). However, the tool description adds no extra meaning about how these parameters relate to counting HN stories. The parameters seem unrelated to the stated purpose, creating confusion. Since the schema already explains each parameter, the baseline is 3, but the description does not resolve the mismatch.

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 clear verb and resource: 'Count current Hacker News front-page stories.' This distinguishes it from most siblings, which focus on URL validation or time/weather. However, the phrase 'Titles discarded' is ambiguous and does not clarify whether the tool returns a count only or processes input shapes. It is not a tautology and has a concrete action.

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. It does not mention any prerequisites, exclusions, or related tools. For a tool that appears to be a shape-checker (based on the schema and siblings), it fails to clarify that it validates inputs rather than actually fetching HN data, leaving the agent uncertain about its role.

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