email_security_posture

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

Beyond annotations (readOnlyHint, idempotentHint), the description adds critical behavioral context: passive DNS-only nature, no SMTP probe, and DKIM probing logic (common selectors + recent dates, custom selectors required). No contradictions with 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 concise (4 sentences) and front-loaded with the core purpose. Every sentence adds value: purpose, dual-use, scoring details, probing specifics, passive nature, and rate limits. No extraneous information.

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 the output schema exists, the description does not need to explain return values. It covers purpose, parameters, behavioral constraints, and rate limits sufficiently, making it complete for an API tool.

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 coverage is 100% with descriptions for both parameters. The description adds meaning beyond the schema by explaining DKIM probing behavior (common selectors, recent dates, custom selectors), which enhances parameter understanding.

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 states the tool analyzes domain email authentication posture (SPF, DMARC, DKIM) with a numeric score and findings. It specifies dual-use for red-team and blue-team, and distinguishes itself by being passive DNS-only with no SMTP probe, unique among siblings.

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 indicates when to use it (analyze email authentication posture) and what it does (passive DNS-only, no SMTP). It provides rate limits but lacks explicit comparison to alternatives or when not to use it, though siblings don't overlap significantly.

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