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

With no annotations, the description carries full behavioral disclosure burden. It only mentions 'Titles discarded,' which is a minor hint but does not explain how parameters are used, whether network access occurs, or what the return value is. The schema's per-parameter notes (e.g., 'discarded after the shape check') are not echoed in the description, so behavior remains opaque.

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 that is front-loaded with the primary action. It is concise with no filler. However, the structure is minimal and does not provide additional context that could aid the agent, such as a note on parameter relevance.

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?

For a tool with 9 parameters, no output schema, and no annotations, the description is grossly insufficient. It does not explain why the parameters exist, how to invoke the tool correctly, or what the expected result format is. An agent cannot confidently call this tool without further assumptions.

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%, so each parameter has an individual description. However, the tool description adds no meaning beyond the schema; it does not explain how parameters relate to the stated purpose of counting HN stories. The baseline of 3 is appropriate since the schema already documents parameters, but the description fails to bridge the gap between them and the tool's function.

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 action: 'Count current Hacker News front-page stories.' However, the presence of 9 unrelated parameters (ref, url, city, etc.) with no explanation of their role creates confusion about what the tool actually does. The purpose is partially clear but not fully distinguished from the parameter set.

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 the many sibling tools (e.g., domain-shape, file-path-ok). There is no mention of alternatives, prerequisites, or exclusions, leaving the agent to infer usage from the name alone.

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