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

Annotations already establish readOnly, idempotent, non-destructive behavior, so the safety profile is covered. The description goes further by disclosing exactly what the response contains — a specific metric inventory including per-link clicks and survey responses — which is meaningful behavioral context an agent can act on.

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?

One tightly packed sentence with the resource stated first and the metric list following. No filler, no redundancy, no restatement of the title.

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 carries return-value disclosure and does so well by enumerating the metric categories. It stops short of covering time-window behavior, data freshness, or result granularity, which are the remaining gaps for a reporting 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%, so the single campaignId parameter is already documented ('Newsletter id from list_newsletters'), giving a baseline of 3. The description adds a small nuance by implying the id can also reference a journey email, which the schema text does not state, but no format or lookup guidance is added.

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 clearly identifies the resource — results/metrics for a sent newsletter or journey email — and enumerates the exact metric set (delivery, opens, clicks, bounces, complaints, unsubscribes, link clicks, A/B subject results, CSAT/NPS). It distinguishes itself from get_newsletter (config) and get_journey_performance by being the per-send results reader, though it never names a sibling explicitly.

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 guidance, no mention of prerequisites (e.g. the newsletter must have been sent), and no routing to alternatives like get_newsletter, check_newsletter, or get_journey_performance. The scope hint ('sent newsletter or journey email') is descriptive of the data, not a usage instruction.

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