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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds that results are paginated and enumerates the returned field categories, which is genuinely useful context beyond the annotations but still omits sort order, default page size, and total-count behavior.

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 purpose and followed by return contents; nothing is redundant. It could be tightened only slightly, since the return-field list is the main payload-bearing clause.

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, listing the returned field categories is necessary and present, which is good. But for a paginated list tool in a crowded family of campaign tools, missing paging defaults and sibling routing leaves the definition only minimally complete.

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 both parameters (page, limit) are documented in the schema, including the 10–100 range. The description only echoes 'pagination' without adding meaning such as default values or paging semantics, so 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 clear verb and resource ('List MailerCloud campaigns') plus the scoping mechanism (pagination). However, it never distinguishes itself from related siblings such as get_campaign, analyze_campaign, or compare_campaigns, so an agent must infer which one to pick.

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 guidance on when to use this versus get_campaign (single fetch) or analyze_campaign (aggregate analysis), and no conditions or exclusions are stated. The only usage signal is the word 'pagination,' which is implied rather than explained.

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