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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does state that the query is discarded, which is a useful note about side effects. However, it does not mention that the other parameters are ignored, nor does it disclose the return format (e.g., whether it returns an integer). Given the tool's simplicity, this is minimally acceptable but not thorough.

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, front-loaded with the core purpose. Every word earns its place, and there is no padding or redundancy. This is exemplary conciseness.

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 simple counting tool, the description is mostly complete. However, the presence of nine parameters, of which only one is relevant, could confuse an agent. The description does not explicitly state that only 'query' is used, though the schema descriptions hint at this. Additionally, the lack of an output schema means the return value is implied but not stated. Given the low complexity, this is adequate but leaves minor gaps.

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 all nine parameters are already described in the schema. The description adds no additional meaning beyond reinforcing that 'query' is the relevant parameter. It does not clarify that the other eight parameters are unused, though their schema descriptions already note they are discarded. Thus, the description adds little value beyond the schema.

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 (count characters) on a specific resource (search query). It is clear and not a tautology. However, it does not differentiate this tool from sibling counting tools like memory-key-count or hn-front-count, so it misses the top score.

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 guidance is given about when to use this tool versus the many sibling counting tools. The description does not mention exclusions, alternatives, or conditions under which this tool is preferred. The agent is left to infer based on the name alone.

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