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 only mentions that the query is discarded, but it does not explain what happens with the other parameters (e.g., ref, url, json) or whether they are validated or ignored. The parameter descriptions in the schema say 'discarded after the shape check' for several fields, suggesting the tool might perform shape checks, but the tool description is silent on this. This ambiguity is a significant transparency gap.

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 brief (two short sentences) and front-loads the core purpose. It is concise and to the point, with no unnecessary filler. However, it is so brief that it sacrifices essential context, which is a structural trade-off. The conciseness itself is good, but the completeness suffers.

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 tool has nine optional parameters, no required fields, and no output schema, yet the description only explains the use of 'query'. It does not clarify the purpose of the other parameters or whether they are used, ignored, or validated. Given the complexity of the schema and the presence of many sibling tools, an agent needs more context to decide when to invoke this tool. The description is inadequate for safe and correct usage.

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 already provides 100% description coverage for all nine parameters, so the baseline is 3. The tool description adds no new parameter semantics beyond mentioning 'query' – it does not clarify that other parameters are ignored or how they interact. The description does not compensate for any schema gaps, but since the schema is complete, this is acceptable.

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 a specific action ('Count characters in a search query') and resource ('search query'). The phrase 'Query discarded' indicates the query is not retained, which adds a behavioral nuance. However, it does not clarify what the other eight schema parameters are for, which could confuse an agent about the tool's actual scope.

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 alternatives. The sibling list includes many shape-check and URL-validation tools, but the description does not mention any exclusion criteria, alternatives, or specific use cases. An agent has no way to know if this tool is appropriate for a given task beyond its name.

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