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 a non-obvious behavior: titles are discarded, so the tool returns a count rather than story metadata. However, it does not describe return format, network dependency, or failure behavior, leaving notable gaps.

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 with the purpose front-loaded and no filler. Every word contributes: the action, the resource, and the critical output limitation are all present.

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 simple count tool, the core purpose is clear and invocation with no arguments is plausible. But the presence of nine unrelated optional parameters, the absence of an output schema, and no annotations leave ambiguity about invocation relevance and exact return shape.

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 baseline is 3. The description does not add parameter-level meaning, and it leaves ambiguous whether any of the nine optional parameters are actually used or all ignored for this tool. 'Titles discarded' is output behavior, not parameter semantics.

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 action and resource: 'Count current Hacker News front-page stories.' The added 'Titles discarded' clarifies the output scope. However, it does not explicitly differentiate from sibling tools like web-fetch or normalize-url, so it stops short of a 5.

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 about when to use this tool versus alternatives, nor any exclusions or conditions. The agent receives no help choosing between hn-front-count and siblings that might also fetch or inspect Hacker News or other URLs.

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