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

No annotations are provided, so the description carries the full behavioral disclosure burden. It adds one useful trait: 'Query discarded' implies no persistence of the query. However, it does not disclose the return format, whether other parameters are ignored, error behavior, or side effects, leaving important behavior unexplained for a tool with nine optional parameters.

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 very concise and front-loaded: 'Count characters in a search query' immediately states the action. The second sentence, 'Query discarded,' provides a relevant behavioral note without redundancy. It is economically written, though arguably too terse for the complexity implied by the input schema.

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?

Given nine optional parameters, no required parameters, no output schema, and no annotations, the description is not complete enough for an agent to confidently invoke the tool. It does not explain which parameter is counted, what the function returns, why the other eight string fields exist, or what 'discarded' means operationally.

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 every parameter is already documented in the schema. The tool description adds little beyond that, but the `query` parameter description aligns with 'Count characters in a search query.' Because the schema does the heavy lifting, the baseline of 3 is appropriate, though the description does not clarify the primary parameter among the nine optional fields.

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 specific action and resource: 'Count characters in a search query.' This clearly identifies what the tool does, especially when paired with the tool name. However, it does not differentiate itself from other count-like siblings such as hn-front-count or memory-key-count, and it does not explicitly tie 'search query' to the `query` input parameter.

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?

There is no guidance on when to use this tool versus alternatives, no mention of expected input context, and no exclusions. The description simply restates the operation without explaining scenarios such as checking query length limits before a search API call. This leaves the agent to infer usage entirely.

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