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 transparency note. However, it does not disclose what happens to the other parameters (some are described in the schema as discarded, but the description itself does not mention them), nor does it describe the return value or any side effects. The single disclosure is 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 extremely short (two sentences), but this is under-specification rather than effective conciseness. It front-loads the main action, but leaves out essential context about the other parameters and the return value. Every sentence earns its place, but there is simply not enough content to be well-structured.

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 9 parameters and no output schema, the description is severely incomplete. It does not explain why the tool accepts many unrelated parameters, what happens if multiple are provided, or what the output format is. An agent cannot reliably know how to invoke the tool correctly, especially given the lack of usage guidance and return type information.

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?

The schema provides descriptions for all 9 parameters (100% coverage), so the baseline is 3. The tool description does not add any meaning beyond the schema; it only mentions 'query' without elaborating on its format or behavior. Since the schema already covers each parameter, the description adds no extra semantic value.

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 clearly states the core action: count characters in a search query. It specifies a verb and resource, which is unambiguous. However, it does not differentiate from sibling count tools like memory-key-count or hn-front-count, and it does not explain why the schema contains 8 other parameters, so the purpose is only partially clarified.

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, nor any mention of conditions or exclusions. The description says nothing about the intended use case or why the other parameters exist. An agent would have no idea whether to call this tool over others for query length checks.

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