dnspeek: inspect a domain's DNS, email auth and TLS

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

Annotations cover the safety profile (readOnly, idempotent, non-destructive, open world), and the description adds substantial context beyond them: latency (1-3 s), price (USD 0.01 / 0.004 per section), a free tier of 5 per IP per UTC day, the heuristic caveat, and an explicit untrusted-input warning for returned page text and on-chain strings. That is rich operational disclosure.

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?

Front-loads purpose, then alternatives, then returns, then cost/limits/caveats, then docs. Every clause carries information an agent needs; nothing is padding.

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?

An output schema exists, yet the description still summarizes the return payload (records, SPF/DMARC/DKIM/MTA-STS, deliverability score_out_of_8, cert expiry/SANs/key/trust), and it covers cost, rate limits, latency, and safety caveats. Nothing material is missing for correct invocation.

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% and both parameters are documented in-schema, so the baseline is 3. The description hints at section selection via 'single section' pricing and enumerates the three sections, but adds no syntax or constraints beyond what the schema already provides.

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?

States a specific verb and resource ('inspect a domain's DNS, email authentication and TLS cert in one call') and explicitly differentiates from siblings rdap_lookup (registration data) and check_domain_availability (availability). An agent can route correctly without opening any schema.

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?

Explicitly names the two adjacent tools and the conditions that select them, plus what the tool does not do ('Heuristic, not an audit'). When-to-use and when-to-use-something-else are both covered.

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