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

With no annotations, the description carries the behavioral burden; it does disclose that titles are discarded and implies a read-only count operation. However, it doesn't explain whether any of the nine accepted parameters are used or ignored, how 'current' data is obtained, or what the result shape is beyond a count.

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?

Two short sentences, each with a purpose. The core action is front-loaded and 'Titles discarded' is a useful clarification with no wasted words.

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 makes the no-required-parameter invocation reasonably clear and notes a key output detail, but with no output schema and nine optional parameters, it fails to state the output type or how the parameters (especially feed) relate to the tool. An agent can call it, but may be uncertain about custom inputs.

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 the schema documents all parameters without help from the description. The description adds no parameter-specific meaning and doesn't clarify which optional parameter, if any, is actually relevant to the HN count.

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 operation: count current Hacker News front-page stories. It doesn't explicitly align or contrast with sibling tools, but the specific resource (HN front page) makes the purpose unambiguous.

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?

There is no guidance on when to select this tool over siblings like web-fetch, fetch-status, or memory-key-count, and no mention of prerequisites or alternatives. The description simply states the function, leaving usage decisions to inference.

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