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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions 'Query discarded', which implies no persistence, but does not disclose that all other parameters are ignored, that the tool is read-only, or that it returns a simple character count. The schema descriptions for each parameter mention 'discarded', but that is in the schema, not the tool description. The behavioral detail is minimal and incomplete.

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 concise: two sentences with no filler. The primary action is front-loaded in the first sentence. While it lacks necessary detail for completeness, that is a completeness issue, not a conciseness issue. As far as conciseness goes, 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 9 parameters, no output schema, and no annotations, the description is insufficient. It does not clarify that only the 'query' parameter is relevant, nor does it specify the return value (presumably an integer length). An agent might mistakenly pass any of the other parameters, and the lack of an output schema means the return format is unknown. The description does not provide enough context for reliable 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% – every parameter has a clear description in the input schema. The tool description adds nothing about parameters, but since the schema already fully documents them, a baseline score of 3 is appropriate. The description does not help select which parameter to use, but the schema handles that.

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 in a search query' – which matches the tool name and implies a length check. However, it does not specify that only the 'query' parameter is used, given the schema contains 9 unrelated parameters (ref, url, city, feed, etc.). It also doesn't differentiate from sibling shape-check tools like domain-shape or figma-url-shape, which similarly validate inputs.

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. The description provides no context about selecting this tool over other length-checking or shape-checking tools, no mention of exclusions, and no indication of what kind of inputs it is appropriate for.

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