Reporter coverage

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: the row granularity, the sort order (volume descending), and the hard cap of 50 rows, which tells the agent results are truncated rather than complete.

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 short sentences, zero filler, and the most important fact (what a row represents) is front-loaded. The sort order and row cap follow as useful qualifiers rather 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 does the necessary work of explaining the returned row shape, its fields, ordering, and cardinality cap. It omits only the default date-window behavior, which the schema already supplies.

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 domain, day_after, and day_before are fully documented in the schema, including defaults. The description adds no additional parameter meaning, which is the expected baseline when the schema carries the burden.

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 states the resource precisely: one row per receiving mailbox provider (DMARC reporter_org) with message-weighted pass/fail counts. An agent knows exactly what data comes back, though it never names a contrasting sibling such as get_alignment_summary to differentiate scope.

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 no when-to-use or when-not-to-use guidance. With siblings like get_alignment_summary and list_sending_sources that also summarize DMARC data, the description leaves the agent to infer which tool answers which question.

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