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

With no annotations provided, the description carries the behavioral burden. It discloses that titles are discarded, which is useful, and 'current' implies a live read rather than a cached or historical count. However, it does not explicitly state whether the operation is read-only, whether network access is involved, or what the exact return value looks like.

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 filler. The primary purpose is front-loaded, and the secondary behavioral note about titles discarded is concise and relevant.

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 is simple and the schema is complete for parameters, but with no output schema and no annotations, the description should more explicitly state that the tool returns only a count and can be invoked with no arguments. The current description is adequate but leaves the return format and parameter irrelevance to inference.

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 itself adds little parameter-specific meaning; 'Titles discarded' vaguely relates to ignoring title-like input, but none of the nine schema properties are directly tied to Hacker News, and the description does not clarify which (if any) parameters matter. The schema already handles this by marking all parameters optional and describing their discarded behavior.

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 specific verb and resource: 'Count current Hacker News front-page stories.' This clearly identifies what the tool does and distinguishes it from sibling count tools like memory-key-count and search-query-len by naming the Hacker News resource explicitly.

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?

The description provides clear context for when to use the tool: whenever a current Hacker News front-page story count is needed. 'Titles discarded' also signals a limitation, implying that this tool is not appropriate if titles or story details are required, though it does not name an alternative.

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