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

Annotations already declare this a read-only, idempotent, non-destructive operation, so safety is covered. The description adds useful scope ('most recent sent broadcasts' as opposed to drafts or scheduled) and the returned metric set, but says nothing about ordering, pagination, or behavior when fewer broadcasts exist than requested.

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: purpose first, then the payload contents, then the usage triggers. Every sentence earns its place and the most decision-relevant information is front-loaded.

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 only one optional integer parameter, no nested objects, and no output schema, the description does enough by enumerating the returned metrics in place of an output schema. It omits ordering/pagination details, which is a minor gap for a tool this simple.

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%, and the single last_n parameter is fully documented in the schema with default and max. The description's phrase 'most recent sent broadcasts' reinforces the recency semantics but adds no syntax or bounds beyond what the schema already states, 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?

The definition gives a specific verb and resource (return performance metrics for the most recent sent broadcasts) and names the exact metrics returned (open rate, click rate, send counts). It clearly distinguishes itself from the plain broadcast getters at the metric level, though it never names a sibling to contrast against.

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?

It gives three concrete triggers ('asks how their emails are performing', 'asks for email stats', 'wants to review recent campaign results'), which map directly to plausible user intents. There are no exclusions or alternative tools named, so an agent must infer the boundary against meisa_get_broadcast or meisa_get_contact_analytics.

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