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

Annotations already declare read-only, non-destructive, open-world behavior, so the bar is lower. The description adds useful context beyond that: the exact six resolvers queried and the fact that results include agreement, a consensus answer, and response times, which tells the agent what a multi-resolver fan-out returns.

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 first clause establishes the scope and the last sentence carries the real payload, so it is front-loaded. But 'Check propagation.' duplicates the first sentence and the opening of the third, a wasted sentence that should have been cut.

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 does part of the return-value work by naming agreement, consensus answer, and response times. Combined with annotations covering safety and 100% schema coverage, it is nearly complete, though resolver list, no auth/rate-limit notes, and return shape details keep it short of 5.

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% with only two parameters (domain, type), so the schema already carries the parameter meaning. The description adds no format or constraint detail beyond it — baseline 3 is appropriate.

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 — checking whether a DNS change has propagated by querying six named resolvers at once. That scope implicitly separates it from the sibling dns_lookup, but no sibling is named, so the differentiation is inferred rather than explicit.

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?

It gives one implied scenario ('Check if a DNS change has propagated'), which is a usable context. However it never states when to prefer this over dns_lookup or any other alternative, nor any exclusions or prerequisites, so guidance remains implied.

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