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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds genuinely useful context beyond them: the exact response envelope, the reportId field added per row, and the authorization prerequisite. It omits pagination/limits and result-size behavior for a potentially large record list.

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 purpose then contract then prerequisites; each sentence carries information. Slightly dense with API-mirroring detail, but nothing is redundant.

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?

Complete enough for a 3-required-param read tool: it documents the return shape (no output schema exists), the filtering semantics, and the access requirement. Only edge behaviors like empty ranges or large result handling are unaddressed.

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 coverage is 67%, and the description compensates by explaining that startDate/endDate filter on reported end date inclusively and that endDate must not precede startDate — semantics absent from the schema. organizationId's 24-hex pattern is only conveyed via the schema, not the description.

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 ('Retrieves DMARC data') scoped to a Suped organization, and clarifies the return payload shape. It does not explicitly distinguish itself from the sibling download_dmarc_report, leaving the read-vs-download distinction to inference.

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?

Gives concrete usage context: dates select reports by reported end date inclusively, endDate must be >= startDate, and regular organization access is required (billing-only insufficient). It stops short of naming when to prefer download_dmarc_report over this tool.

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