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

With no annotations, the description carries the full burden, but it only states 'input discarded'. This is a useful non-retention hint, yet it does not disclose whether the tool performs network access, what it returns, whether it is read-only, or what side effects exist. The schema's per-parameter 'discarded' notes repeat this idea, so the description adds minimal behavioral context beyond structured fields.

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 short, but this is under-specification rather than effective conciseness given the tool's nine-parameter schema and no output schema. It is a fragmented two-word phrase plus a fragment, lacking a sentence structure that front-loads actionable guidance.

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 definition is severely incomplete for a tool with 9 optional parameters, no output schema, and no annotations. It fails to explain what the count refers to, which parameter(s) to supply, what the return value is, or how the input is used before being discarded. An agent cannot reliably select or invoke this tool from the description alone.

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 adds no parameter meaning beyond 'input discarded', which is already reflected in each parameter's schema description. It does not clarify which of the nine parameters the 'HTML numeric-entity count' actually operates on, but per the rubric the schema already documents parameter-level semantics.

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 phrase 'HTML numeric-entity count' suggests a counting operation, but it is a noun phrase rather than a clear verb+resource statement, and it does not explain what input is counted. The schema lists nine generic parameters (url, city, feed, host, etc.), none obviously containing HTML, so an agent cannot tell what to pass. 'Input discarded' adds confusion rather than clarifying the tool's 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 gives no guidance on when to use this tool versus alternatives. Sibling tools like hn-front-count, memory-key-count, and search-query-len suggest overlapping counting/checking behaviors, but no distinction or condition is provided. There is no when-to-use, when-not-to-use, or alternative naming.

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