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

With no annotations, the description must carry behavioral disclosure. It reveals only that titles are discarded; it doesn't state the return type, that it performs a live network fetch, or how failures or irrelevant parameters are handled.

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, main action front-loaded, no filler. 'Titles discarded' is terse to the point of ambiguity but still earns its place as a behavioral hint.

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?

A tool with nine optional parameters and no output schema needs more than a purpose statement. The description omits the relevant parameter, return shape, network behavior, and whether no-argument invocation is supported, so an agent cannot reliably call it.

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 coverage is 100%, so the baseline is 3. The description's 'Titles discarded' aligns with the feed parameter's description but never tells the agent which of the nine optional parameters applies to this tool.

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?

Clearly states a specific action ('Count') and unique resource ('current Hacker News front-page stories'), which separates it from sibling fetch/count tools. The second sentence is cryptic, but the core purpose is 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?

No information about when to choose this tool over web-fetch, fetch-status, or other siblings. It does not mention prerequisites, when-not-to-use, or input requirements.

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