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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds genuinely useful context beyond that: the free SnoopScan key requirement (auth), the flat per-depth pricing, and the 6/12 archived snapshot counts that affect runtime.

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-loads the deliverable, then the depth semantics, then pricing and the key requirement. Efficient overall, though the trailing one-line 'Needs a free SnoopScan key.' sits slightly apart from the flow.

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?

An output schema exists so return values need not be described, and annotations cover the safety profile. Depth, pricing, and the auth prerequisite are covered, leaving only sibling disambiguation unaddressed.

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?

Schema coverage is 0%, so the description carries the burden and does so well for `depth`, spelling out what quick, buyer, and deep each add and their archive-sample sizes. The `url` parameter is left implicit, which is a minor gap given its obviousness.

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 and resource: a buyer's report on a domain covering key findings, concerns, and unanswerable questions. It is clear and distinct in tone, but never explicitly differentiates itself from close siblings such as domain, domainScreen, or domainSnapshots.

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 depth tiers (quick/buyer/deep) give strong implied guidance about scope, and 'before buying it' implies the acquisition use case. However, there is no explicit when-to-use versus the many related domain* siblings, nor any exclusion guidance.

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