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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It reveals nothing about whether the tool performs network lookups, requires message content or DNS records, is read-only, or what its output shape might be. This is inadequate for an operational tool.

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 extremely short, but this is under-specification rather than effective conciseness. It contains no useful content, no examples, and no structure that would help an agent act on it.

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?

This is a 3-parameter tool with no annotations and no output schema, yet the description explains nothing about how the parameters relate, what is required, or what result to expect. It is entirely inadequate for correct invocation and interpretation.

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?

The input schema has 100% description coverage, but all three parameter descriptions are generic and unhelpful ('Input to process', 'Domain to process', 'Selector to process'). The tool description adds no meaning beyond the schema. Under the high-coverage baseline, a 3 is appropriate, though the schema descriptions contribute little real semantic value.

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 'Dkim Check: Dkim Check' is a pure tautology that merely restates the tool name. It provides no verb, resource, or scope, and gives no indication of what the check actually returns or verifies. The name hints at DKIM checking, but the description itself adds zero clarity.

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 guidance about when to use this tool, what inputs are appropriate, or how it differs from related siblings like x402-dmarc-check, x402-spf-validate, or x402-email-security. An agent cannot determine when DKIM checking should be invoked versus alternatives.

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