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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so safety is covered. The description adds one genuinely useful trait not in annotations: the call is 'Free' and does not consume data credits. It says nothing about freshness of the balance, whether it errors when no account is connected, or the agency-wide scope of the figures.

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?

One sentence, front-loaded with the primary resource and with the cost note in the right place at the end. Slight awkwardness in the long relative clause 'how much of the agency's monthly SEO data limit Royally has used this month', but nothing is wasted.

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 no output schema, the description correctly enumerates the three things returned (connected services, credit remaining, monthly usage). For a zero-parameter read-only status tool this is nearly complete; only the failure/empty-account behavior is left implicit.

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 tool takes zero parameters, so the baseline is 4. The description usefully clarifies the implicit scoping that no schema field can express – figures are for the agency's own DataForSEO account and cover 'this month'.

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 names the specific resources returned: connected SEO data services, DataForSEO credit balance, and monthly SEO data limit consumption. It is clear what the tool reports, but it does not distinguish itself from sibling seo__ tools that also touch the SEO data account (e.g. seo__domain_overview, seo__rankings), so an agent must infer that this is the non-consuming status check.

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 explicit when-to-use or when-not-to-use guidance is given. The trailing 'Free.' implies this should be called before spending credits on the other seo__ data tools, but that relationship is never stated and no alternative is named.

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