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

Annotations already declare this as a safe, read-only, idempotent search with no destructive behavior. The description adds that results include first-term and renewal prices, which is useful output context, but it does not discuss result limits, ranking, or thoroughness of the 'lookalike' behavior.

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 filler. Every element (action, resource, use case, return info) 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 simple one-parameter, read-only search with full schema coverage and annotations that cover safety, the description is nearly complete. Minor gaps remain around result set behavior and how 'lookalike' domains are generated, but none are critical for correct invocation.

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 100% and the single parameter 'q' is already documented as 'Brand or domain, e.g. acme.' The description adds no additional meaning about formatting, scope, or interpretation beyond the schema.

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 verb ('Find') and resource ('available lookalike domains') with the added context of cold email and pricing. It is easy to distinguish from siblings like buy_domains and list_bought_domains, but does not explicitly call out those alternatives.

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?

Usage is implied by 'for cold email,' suggesting when to use this search. However, it does not name alternatives (e.g., use buy_domains to purchase) or state when not to use it, leaving routing to the agent's inference.

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