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

No annotations are provided, so the description carries full responsibility. It only mentions 'Titles discarded,' implying output is a count, but does not disclose that the nine input parameters are largely irrelevant to the core function (many are explicitly 'discarded'). It also omits any side effects, rate limits, or error behavior. The parameter disposal is a behavioral trait that is left unexplained.

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 two short sentences with no fluff. The core action is front-loaded, and the additional note about titles is concise. It is appropriately sized for a simple tool, though it could benefit from a bit more context without losing conciseness.

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 parameters (all optional) and no output schema. The description does not explain why these parameters exist, what the count represents, how to interpret the result, or any limitations. It also does not clarify that the parameters are shape-check placeholders, which is a significant gap for a tool with such a large schema. The description is too minimal to be fully usable.

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%, and each parameter's description already explains its own role (e.g., 'Git ref name; discarded after the shape check'). The tool description adds no extra meaning about parameters beyond the schema. Given the high coverage, a baseline of 3 is appropriate.

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 action: 'Count current Hacker News front-page stories.' This is a specific verb+resource. It does not explicitly differentiate from sibling tools, but the purpose is unique enough to stand alone. The 'Titles discarded' hint adds minor clarity about output scope.

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 alternatives. There is no mention of prerequisites, edge cases, or when to prefer a sibling tool. The description gives no context for selecting this over, say, web-fetch or fetch-status.

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