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

With no annotations, the description carries the full burden. It discloses that titles are discarded and implies a count is returned, but it does not mention network access, rate limits, or how the 9 unrelated parameters affect behavior. This is minimal transparency.

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 sentences is concise, but it is under-specified, not appropriately concise. The description omits essential information about how to invoke the tool with the given parameters, making it inadequate rather than efficiently brief.

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 optional parameters, no output schema, and no annotations, this description is severely incomplete. The agent has no idea which parameters are relevant, how they map to the tool's purpose, or what the expected return value is beyond a vague 'count'.

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 baseline is 3, but the description adds no parameter information. More critically, the parameters (ref, url, city, feed, etc.) seem unrelated to counting HN stories, and their schema descriptions (e.g., 'discarded after the shape check') contradict the tool's stated purpose, making the parameters misleading.

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 verb ('Count') and resource ('current Hacker News front-page stories'), which is specific. However, it does not differentiate from any sibling (no other HN tool) and the mention of 'Titles discarded' adds minor confusion without clarifying the tool's scope.

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 on when to use this tool vs alternatives. There is no mention of context, prerequisites, or exclusions. The description simply states what it does, leaving the agent to infer usage.

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