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

The readOnlyHint annotation already indicates a safe read operation. The description adds behavioral context by enumerating the specific metrics calculated, which goes beyond the annotation. It does not detail edge cases like whitespace handling or reading speed assumptions, but given the annotation coverage, this is adequate.

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 a single, front-loaded sentence with no redundancy. Every word contributes to explaining the tool's functionality.

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 is simple, but without an output schema, the description should clarify what the tool returns. It lists the metrics counted but does not explain the response format or units for reading/speaking time. This is a minor gap for an otherwise clear tool.

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 has one required 'text' string parameter with no description (0% coverage). The description refers to 'in text,' which confirms the parameter is the input to analyze, but adds no additional syntax, constraints, or format details. Since the parameter name is self-explanatory, the description provides marginal added 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 uses the verb 'Count' with a clear resource list: words, characters, sentences, paragraphs, and reading/speaking time. This distinguishes it from the similar 'character-counter' sibling by covering more metrics.

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?

The description clearly implies its use case: analyzing text to get quantitative metrics. However, it does not explicitly mention when to use it versus 'character-counter' or other text analysis tools, lacking exclusions or alternatives.

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