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

With no annotations, the description carries the burden of behavioral disclosure. It communicates the key scoping behavior (one record type per call) but does not describe return format, error behavior, or whether an external network query is performed. This is adequate but leaves the safety and output profile largely implicit.

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 sentence states the core action, and the second sentence packs all alternative routing into compact, scannable clauses. Every part earns its place with zero filler.

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 two-parameter lookup, the selection context is nearly complete, but invocation details are not. There is no accepted-value list for record_type, no return description, and no output schema or annotations to fill the gaps, so an agent has enough to choose the tool but not quite enough to call it with full confidence.

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?

Input schema descriptions cover 0% of parameters, so the description must compensate, but it only implies the domain and record_type roles. It clarifies that record_type is a single type, yet it never lists accepted record types or domain formatting, leaving an agent to guess beyond the default A.

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 opens with a specific verb and resource: 'Resolve ONE DNS record type for a domain,' immediately distinguishing this from broader domain tools. It names sibling alternatives for different use cases, so an agent can disambiguate without inspecting schemas.

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 explicit routing guidance: use /domain/intelligence for all record types at once, /web/audit or /security/posture for a bundled audit, and /domain/due-diligence for mail-security plus scored verdict. These are concrete when-to-use conditions and clear exclusions for the current tool.

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