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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral context beyond those annotations: results are 'still held by the current registrant' and have 'time-sensitive acquisition windows,' which helps an agent understand the nature and urgency of the data. It doesn't cover pagination or rate limits, but with strong annotations that is acceptable.

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 compact and front-loaded: it opens with the core action and scope, then adds contextual detail, filter capabilities, and related tools in three sentences. It wastes little space. It loses a point because the 'drop date' filter reference is an inaccuracy that should ideally be corrected, but as a structure it is efficient.

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 tool with 15 optional parameters, an output schema, and 30+ sibling tools, the description gives a useful orientation and mentions related tools but lacks explicit differentiation from key siblings like 'deleted' and 'monitor.' It also claims a 'drop date' filter that does not exist in the schema. Given the complexity, the description is adequate but leaves gaps in alternative routing and parameter accuracy.

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 description coverage is 100% and the schema itself provides rich parameter semantics (especially for keyword, position, status, and sort). The tool description, however, lists filters including 'drop date,' but there is no drop_date parameter in the schema. This is misleading and could cause an agent to attempt an unsupported parameter. Because the description adds no value beyond the schema and even introduces an inaccurate filter, the score is below baseline.

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 clearly states a specific action ('Search') and the resource: 'domains in the deletion cycle: expired, in redemption, or pending delete.' It adds scope by noting these are 'still held by the current registrant,' which helps differentiate from related tools like 'deleted.' However, it doesn't explicitly name what it is not or contrast with siblings, so it falls short of a 5.

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 when searching for domains in the deletion cycle and lists 'Related: monitor, deleted, whois' as potential alternatives. However, there is no explicit when-to-use or when-not-to-use guidance, no conditions, and no explanation of how this tool differs from 'deleted' or 'monitor.' The context is clear but the exclusions and alternative-selection logic are left to inference.

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