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

With no annotations, the description carries the full burden, but it only discloses that titles are discarded. It does not state whether this is a network fetch, any rate limits, authentication needs, or what happens with the supplied parameters (which appear to be ignored). This is insufficient for an agent to predict the tool's behavior.

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 short (two sentences) but not effectively concise—it omits critical usage and parameter context. It reads as truncated rather than strategically trimmed, so it fails the 'every sentence earns its place' test because the 'Titles discarded' sentence adds little without parameter explanation.

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 9 optional parameters, no output schema, and no explanation of which parameters to supply or what the return format is. An agent cannot correctly invoke this tool with confidence; the description is fundamentally incomplete for its complexity.

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 coverage is 100%, but each parameter description is generic and unrelated to counting HN stories (e.g., 'ref' is 'Git ref name; discarded after the shape check'). The tool description adds no information about how these parameters influence the outcome, so the semantic gap is large despite the schema text.

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 a specific verb and object: 'Count current Hacker News front-page stories.' This is unambiguous and distinguishes it from sibling shape-checking tools like 'domain-shape' and 'url-shape.' The 'Titles discarded' clause adds a small scoping hint.

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 given on when to use this tool versus alternatives, no prerequisites, and no mention of how the 9 optional parameters relate to the counting operation. The agent is left to guess whether any parameters are needed or how this differs from other retrieval tools.

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