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

Beyond the readOnlyHint/destructiveHint/openWorldHint annotations, the description discloses that it returns the record plus where to place it, that no credit is consumed, and that it requires the Pro plan. The read-only framing ("record to copy into DNS") usefully clarifies the "Create" verb rather than contradicting the annotations; it stops short of describing pagination or per-type output details.

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?

Three tight sentences, front-loaded with the capability and record types; the return behavior, cost, and plan constraint each earn their place. No redundancy or filler.

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 14-parameter tool with no output schema, the description compensates by stating what is returned ("the record to copy into DNS, with where to put it"). Combined with 100% schema coverage, an agent has what it needs; only per-type invocation nuance is left implicit.

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% across all 14 parameters, so the schema already carries full parameter meaning (including per-type scoping like "SPF:", "DMARC:", "BIMI:"). The description adds no syntax or format guidance beyond naming the record types already exposed in the enum, so the baseline 3 applies.

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+resource ("Create the exact DNS setting") and enumerates the four supported record types (SPF, DMARC, BIMI, MTA-STS), which map directly to the `type` enum. An agent can immediately tell this generates DNS records for email authentication, cleanly distinct from the verification/lookup 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?

Usage is only implied by the framing ("so its email is trusted and harder to spoof") and the plan note. It never states when to pick this over sibling verification tools or when one record type is appropriate versus another, so the agent must infer intent from context.

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