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

Annotations already declare readOnlyHint=true, so the safety profile is known. The description adds that it 'Returns what passed, what failed and why', disclosing the output format and diagnostic nature, which goes beyond the annotation and helps the agent set expectations.

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, information-dense sentence that front-loads the core purpose and then lists the eight criteria. It is efficient with no fluff, though the long enumeration could be broken into a structured list for readability. Overall it earns its place.

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 single-parameter read-only tool, the description is complete: it explains the eight evaluation criteria and the nature of the output. It doesn't address edge cases or error handling, but those are unlikely to be critical given the simplicity. No output schema exists, so the description reasonably covers what is returned.

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 covers the single parameter 'text' with a clear description ('The text message as it would be sent'), so baseline is 3. The tool description doesn't add further parameter-specific detail, but it does explain what the tool does with the input, which is sufficient given the high schema coverage.

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 verb ('Checks') and a precise resource ('sales follow-up text message') and enumerates eight distinct practices it evaluates. This clearly distinguishes it from sibling tools like write_follow_up_texts or rewrite_follow_up_text, which generate text, making its purpose unambiguous.

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 implies a clear use case: to evaluate an existing text against best practices. While it doesn't explicitly name alternatives or state when not to use it, the contrast with generation siblings is evident from the wording, so an agent can infer the appropriate context.

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