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

With no annotations provided, the description must carry the burden of behavioral disclosure. It only states 'Titles discarded,' which is a minor output note, and does not indicate whether the tool is read-only, what network access it requires, or how it handles the parameters. The schema descriptions hint at discarding after checks, but the description itself adds little beyond that.

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 extremely concise at two short sentences, front-loading the core action and the note about titles. It earns a high score for brevity and structure, though it sacrifices necessary context.

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?

Given the tool has 9 parameters, no output schema, and no annotations, this description is severely lacking. It doesn't explain how to invoke the tool, which parameters matter, what the return value looks like, or any edge cases. An agent would have difficulty using it correctly without more information.

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 already documents all 9 parameters. The description adds no parameter-specific information and fails to explain why these parameters exist for counting HN stories, creating confusion. Baseline 3 applies because the schema covers semantics, but the description doesn't compensate for the disconnect.

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: 'Count current Hacker News front-page stories,' with a note that titles are discarded. This distinguishes it from generic fetch tools, but the input schema lists 9 unrelated parameters that muddle the purpose and don't clarify how they relate to the counting function.

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 no guidance on when to use this tool versus sibling tools like web-fetch or fetch-status. It doesn't mention alternatives, exclusions, or conditions for use. The only implied usage is for counting HN stories, but there is no explicit when/when-not guidance.

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