check_email_security

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

With no annotations, the description carries the full disclosure burden. It partially meets it by stating what is queried and that a 0-100 score is returned, implying a read-only live DNS inspection. It does not disclose that lookups happen against live DNS, whether the call is latency-prone, any rate limits, or how partial failures are handled.

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?

A single front-loaded sentence that names the verb and resource before listing the checks. The enumeration is long but every item is a real inspected signal, so nothing is padding; slightly list-heavy but 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?

With no output schema, the description should hint at return values, and it does via the overall 0-100 score plus the component checks (the schema also notes one result row per domain). For a read-only audit tool this is close to sufficient, missing only the per-component result shape and failure behavior.

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%, so the schema already explains domain, domains (with its override behavior), and checkDkim's cost tradeoff. The description only weakly reinforces the domain scope and DKIM selector probing, adding no syntax or format detail beyond the schema. Baseline 3 applies.

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 gives a specific verb ('Check') and resource ('a domain's DNS and e-mail security posture') and enumerates the concrete signals it inspects (SPF, DMARC, DKIM selectors, providers, registrar, domain age). It is clearly distinguishable from the sibling validate_emails in spirit (domain-level posture vs. individual address validation), but that differentiation is never stated.

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?

There is no explicit when-to-use, when-not-to-use, or alternative routing. An agent gets no help deciding between this and validate_emails, or knowing that a full score requires the DKIM probe. Usage is only inferable from the enumerated checks.

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