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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds that results are aggregated per campaign across six metrics, which is useful context, but says nothing about pagination behavior, result freshness, or typical result size.

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?

Two short sentences, front-loaded with the resource and its returned fields. The trailing 'GET /Emails/Report' is API trivia that adds little for an agent, but the overall text is tight and waste-free.

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?

There is no output schema, so the description carries the burden of indicating what comes back — and it does list the six metric families per campaign. Pagination and sort parameters are handled by the schema, leaving no critical gap for a read-only listing 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% — page, page_size, search, and sort_order are all documented in the schema, including the next_page chaining hint. The description adds no parameter meaning beyond that, 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?

Clear verb (report/list summaries) plus resource (sent email reports) and an explicit enumeration of the metrics returned per campaign (sends, opens, clicks, bounces, unsubscribes, complaints). It is distinguishable from the single-metric siblings (get_email_opens, get_email_clicks) by being an aggregate summary, but it never explicitly distinguishes itself from benchmark_get_email_report or benchmark_list_emails.

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?

No when-to-use, prerequisites, or alternatives are given. With siblings like benchmark_get_email_report and the per-metric tools (get_email_opens, get_email_clicks, get_email_bounces), the agent is left to infer which to call to get campaign vs. per-recipient data.

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