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

Annotations already cover safety (readOnlyHint, destructiveHint false), yet the description still adds real behavior: cursor-pagination loop semantics and the 202-with-job_id async response path. It doesn't mention authorization or event payload shape, but the operationally risky case (large campaigns) is disclosed.

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 with zero filler; the core purpose comes first, then paging, then the async fallback in order of likely need.

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 covers the key return-shape facts an agent needs (next_cursor, job_id). What an individual event object contains and whether the 202 case blocks the cursor flow are left unstated, a minor gap for a 4-param read 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 coverage is 50%: limit and cursor already have descriptions, kind is an enum. The description restates cursor semantics rather than adding format detail, and campaign_uid is undocumented in both places. Baseline 3 is appropriate.

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 ('List the individual events of a campaign') and enumerates the four kinds, which cleanly separates it from aggregate siblings like get_campaign_inbox_breakdown and get_campaign_summaries. An agent can identify it without opening the schema.

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 explicit operational guidance for cursor paging ('pass the reply's next_cursor back until it is null') and routes the large-campaign case to mailblaze_get_report_job by name. It doesn't explicitly contrast with the aggregate siblings, but the 'individual events' framing implies the distinction.

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