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

With no annotations, the description carries the full transparency burden; it only adds 'Query discarded,' a useful data-handling trait, but says nothing about return values, errors, normalization, or whether any data leaves the environment. The claim is not contradictory, but it is too thin for confident invocation.

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 two sentences are short, front-loaded, and free of repeated schema content. The brevity is arguably under-specification for a nine-parameter tool, but as pure conciseness it is efficient.

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 nine optional parameters, no annotations, and no output schema, a two-sentence description is not complete. It does not state what the function returns, which parameters are valid 'search queries,' or how the other parameters are handled, so an agent lacks critical information for correct invocation.

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; all nine parameters have individual descriptions. The tool description adds no meaning beyond the schema and does not clarify why parameters such as ref, city, and feed are accepted for a 'search query' length tool, preventing a higher score.

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 concrete action ('Count characters') and a specific resource ('a search query'), and the tool name reinforces it; this is enough to distinguish it from siblings like memory-key-count. However, it does not explain how the other eight schema parameters relate to the stated purpose, so clarity is not perfect.

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 when-to-use guidance is given and no alternatives are mentioned, despite many similarly named sibling tools. 'Query discarded' hints at a safe stateless use, but an agent cannot tell when search-query-len should be preferred over memory-key-count or hn-front-count.

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