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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description adds a genuinely useful non-annotation trait: usage-based billing with a default per-request cost estimate, plus a documentation pointer.

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?

Front-loaded purpose in the first clause, with the docs link and pricing block kept separate. Slightly marred by the awkward 'you will find obtain' phrasing, but no wasted content.

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?

With an output schema present, the description need not enumerate return values, and it already states the return is a list of available dates. Combined with annotations and a parameterless schema, an agent has what it needs to call this correctly.

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 input schema has zero parameters, which is the baseline-4 case. The description correctly frames the tool as parameterless, and there is nothing extra to document.

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?

States a specific outcome — returning the list of dates that can be used in the first_date/second_date fields of the Domain Metrics by Categories endpoint. That distinguishes it from the many sibling post_dataforseo_labs_* tools, though it references a parent endpoint that is not itself in the sibling list.

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 usage by tying the output to first_date/second_date of another endpoint, so an agent can infer 'call this before setting those dates.' It does not state a when-not condition or name an alternative for discovering valid ranges.

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