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

With no annotations, the description carries the full behavioral burden. It does disclose that titles are discarded and that the count reflects the current front page, but it does not specify the return format, network dependency, failure behavior, or input handling, so transparency is only partial.

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 action is front-loaded and the second sentence adds a useful behavioral qualifier. Every word contributes.

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?

Despite the tool's simple core purpose, the context is incomplete: there is no output schema, no annotation safety information, no indication of which (if any) of the 9 schema parameters should be supplied, and no return type stated. An agent would have to guess whether to call it with zero arguments or with a feed/URL parameter.

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 tool description adds no direct parameter mapping and does not clarify why 9 unrelated optional parameters exist; the only shared hint is the phrase 'titles discarded,' which also appears in the feed parameter, but the connection is not explicit.

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 names a specific verb ('Count'), a concrete resource ('current Hacker News front-page stories'), and an output qualifier ('Titles discarded'), making the tool's function unambiguous. This also separates it from the sibling utilities, none of which target HN front-page counting.

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?

Usage is implied but not stated: an agent can infer 'use when you need the current number of HN front-page stories,' yet there is no explicit when-to-use/when-not-to-use guidance or comparison to alternatives like web-fetch. The lack of exclusions or prerequisites leaves the guidance at the implicit level.

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