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

Annotations already indicate read-only, non-destructive behavior, so the description adds value by specifying the audit scope, the PASS/WEAK/FAIL output format, and the prioritized fix list. It also discloses pricing. It does not detail rate limits or exact response structure, but the additions are meaningful beyond the annotations.

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 with the key value proposition: one-call posture audit with PASS/WEAK/FAIL. Every clause earns its place, including the specific checks, the use cases, and the pricing. There is no redundant 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?

Given one simple parameter and no output schema, the description explains the verdict categories, the checks performed, and the deliverable (fix list). It gives an agent enough context to select and invoke the tool correctly without needing additional documentation.

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 there is only one parameter (domain), so the schema already fully documents it. The description confirms 'for a domain' but does not add meaningful new parameter semantics beyond what the schema provides, placing it at the 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 states a clear purpose: a DNS/email security posture audit producing PASS/WEAK/FAIL verdicts. It names concrete checks (SPF, DMARC, MX, CAA, DNSSEC, nameserver redundancy) and a prioritized fix list. This clearly distinguishes it from single-purpose siblings like dns_lookup or email_domain_check.

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 explicitly says it is for 'security, deliverability and compliance automation', giving clear context for when to use it. It does not explicitly name sibling alternatives or exclusions, but the 'bundle' framing and the checks listed make the intended use case evident.

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