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

With no annotations, the description must disclose behavioral traits. 'Posture' suggests a summary or assessment, but it does not explain what the tool actually does with the input, what it returns, whether it performs live DNS lookups, or any limitations. The description is too sparse to provide meaningful behavioral transparency.

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 a single, concise phrase that fronts the key topic and scope. It is not wasteful, and the colon structure is efficient. However, it is almost too terse, as it sacrifices necessary detail for brevity.

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?

Although the tool has only one parameter and no required fields, the description fails to explain what that parameter represents or what 'posture' means in terms of output. The agent cannot reliably construct a correct query without additional context. An output schema exists, but the input semantics are a critical missing piece.

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 0%, and the description does not mention the parameter 'q' at all. The agent cannot determine whether 'q' expects a domain, an email address, or something else. There is no compensatory explanation in the description, leaving the parameter completely opaque.

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 identifies the resource (email security) and the specific scope (SPF, DMARC, DKIM posture). It differentiates from sibling email-related tools like 'email' or 'emailrep' by focusing on DNS-based authentication records. However, it lacks a verb like 'check' or 'assess', making the action implicit 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?

No guidance is provided on when to use this tool versus alternatives. There is no mention of expected input (e.g., a domain name), no prerequisites, and no exclusions. The agent is left to infer that it should be used when email security posture is needed, but this is not explicitly stated.

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