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

With no annotations, the description carries the full disclosure burden, but it only says the query is discarded. It does not state the return type, behavior on empty input, counting semantics, or why parameters like json, url, and ref mention unrelated shape/validation checks.

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 short, scannable, and front-loaded with the action. It earns its conciseness, though it omits important operational details that a slightly longer description should provide.

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 nine optional parameters, no output schema, and no annotations, two sentences are insufficient. An agent cannot determine what to pass, what the return value looks like, or why the schema includes so many unrelated-looking fields.

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?

Although the schema covers all parameters, the descriptions are inconsistent with the tool-level description. Only query is explicitly tied to length checking, while ref, url, json, and others reference unrelated behaviors like shape checks and normalization. The description never explains which parameter should be used as the search query or what the other eight are for.

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 ('a search query'), and the discarded note signals a stateless check. However, the input schema accepts nine unrelated string parameters and the description does not explain their relationship to the query, muddying 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 on when to use this tool versus its many siblings. With tools like memory-key-count, validate-json, and multiple shape-check tools present, an agent needs at least a hint about what kind of input warrants calling this tool.

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