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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description adds genuinely non-obvious behavior — a per-call price (0.02 USDC on Base), an x402 payment handshake requiring two invocations, and live DNS resolution at call time. It stops short of describing failure modes (e.g., unresolvable domain, insufficient payment) or whether results are cached.

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?

Information-dense but crammed into a semicolon-joined run-on; the vendor/price prefix, the HTTP GET URL, and the payment handshake compete with the actual capability statement. The raw endpoint URL and duplicated input example are largely redundant for an agent that invokes through MCP, and the payload is not front-loaded on what the tool returns.

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?

For a read-only DNS analysis with no output schema, the description does a solid job telling the agent what comes back: current MX/SPF/DMARC state, DKIM selector classifications, and exact per-stage DNS records plus Zoho/Google/Microsoft console steps. The remaining ambiguity is the shape of the response (single object vs. staged list) and how multi-domain or subdomain cases are handled.

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 both `q` and `x_payment` are already documented in the schema, including the base64 x402 payload and the 0.02 USDC terms returned on the first call. The description restates the same JSON input example and payment purpose without adding format rules, validation constraints, or defaults, so it sits 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 names a specific deliverable — a staged DMARC remediation plan that ends at p=reject — and enumerates the inputs it inspects (MX, SPF, DMARC, per-selector DKIM status, null-MX parked domains). That is far more specific than the title alone. The one gap is that a sibling `kyreos_dmarc_audit_tool` exists and the description never says how this plan differs from that audit, so the agent must infer the boundary.

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 real procedural guidance for the two-step paid call: first call without x_payment to obtain the x402 terms, second call with the signed payment to get the result. However, there is no guidance on when to choose this over the sibling audit tool, no prerequisites (e.g., that the domain must already exist / be resolvable), and no statement of what happens if payment terms expire.

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