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

Annotations supply readOnlyHint=true, and the description adds real context beyond them: pagination behavior, supported filter axes (type/status/audience), sorting, and the underlying REST path GET /campaigns. It stops short of disclosing defaults or rate limits, but the added operational detail is meaningful.

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 compact sentences with zero filler; the core purpose and filter scope are front-loaded and the REST path is appended as a useful, non-redundant aside.

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?

For a read-only list tool with full schema coverage and safety annotations, no output schema to explain, and no destructive behavior to warn about, the description covers what an agent needs. Slightly more on default page size or response shape would make it fully self-sufficient.

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 all seven parameters are already documented in the schema with defaults and enum meanings. The description's 'type/status/audience filters and sort' summary maps to the parameters but adds no syntax or format detail beyond the schema, 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?

States a specific verb+resource ('List the account's campaigns (email sends)') and disambiguates campaigns from other entities like reports or automations. It does not explicitly contrast with sibling mailchimp_get_campaign (single-fetch vs list), but the resource and scope are unambiguous.

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?

The description notes pagination and optional filters, which implies the use case (browsing/querying campaigns), but it gives no explicit when-to-use guidance versus mailchimp_get_campaign or mailchimp_get_campaign_report, nor any prerequisites.

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