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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so safety is well covered. The description adds one piece of real behavioral value — that the output includes warnings about the 10-lookup limit — but says nothing about the returned record format, what happens with conflicting inputs, or how strict/-all is chosen by default.

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?

A single front-loaded sentence that establishes the artifact first and the warning behavior second, with no padding. Slightly long and comma-heavy, but every clause carries 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?

For a 7-parameter, all-optional generator with no output schema, the description should at minimum explain what is returned and how the optional mechanism flags combine. It covers the purpose and one output trait (lookup-limit warnings) but leaves the caller guessing about the record format, defaults for the boolean flags, and the meaning of the undocumented parameters.

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 only 43%: strict, includes, and providers are documented in the schema, while a, mx, ip4, and ip6 have no description anywhere. The description's 'email services it sends with' loosely gestures at providers/includes but explains none of the mechanism flags, so it does not compensate for the coverage gap.

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 — 'Build a valid SPF TXT record for a domain' — and names the input basis ('the email services it sends with'), which separates it from the sibling check_spf, which inspects an existing record. It stops short of naming that sibling explicitly, so the distinction must be inferred from the verb.

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?

Usage is implied by 'generate' versus the check_* siblings, but the description never says when to use this tool rather than generate_dkim_record, generate_dmarc_record, or check_spf, nor that it is for creating new records rather than auditing existing ones. No preconditions or exclusions are stated.

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