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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is fully covered by structured fields. The description adds only that results are aggregated over a range; it says nothing about whether missing dates default to a window, whether the call is expensive, or the shape of returned counters.

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 eighteen-word sentence with the resource and the returned metrics front-loaded; nothing is padded or repeated. It is arguably too terse rather than too verbose, which costs less than 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?

With no output schema, the description carries the burden of describing the return value, and it does so only at a high level (pass/fail totals, alignment rates) without indicating structure or units. The optional from/to parameters and any default window are left unexplained, which is a real gap for a stats tool.

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%: id, from, and to are each documented in the schema, so the baseline of 3 applies. The description adds no extra semantics such as whether from/to are inclusive, what happens if only id is supplied, or maximum range limits.

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 (implied retrieval) and resource: DMARC pass/fail totals and alignment rates for a domain over a date range. That is clear enough to act on, but it never distinguishes itself from close siblings like get-dmarc-report, get-dmarc-forensic-report, or list-dmarc-reports, which an agent must choose between.

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?

The phrase 'over a date range' hints at aggregated analysis rather than raw report retrieval, but there is no explicit when-to-use, no mention of prerequisites (e.g., DMARC reporting must be enabled, a report uploaded), and no routing to get-dmarc-report for individual reports. Usage must be fully inferred from the name.

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