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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so safety is covered. The description adds value by enumerating what the response contains (status, template, parameters, counts) and the underlying endpoint, but says nothing about not-found handling or permission requirements.

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, front-loaded sentences with no filler; the selector and the returned fields come first. The second sentence is a bare endpoint path, which is the only mildly wasteful element.

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?

There is no output schema, so listing the returned fields is necessary and present. However, the description does not clarify how API campaigns differ from the regular campaigns exposed by sibling tools, nor what happens when the id is unknown, leaving a small but real gap for a lookup 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% and the single campaign_id parameter is documented as an AiSensy record id with a format pattern. The description's "by id" phrasing repeats that without adding format or sourcing detail, 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 specific resource (one API campaign) and the selector (by id), which distinguishes it from aisensy_list_api_campaigns at a glance. It is slightly less crisp than a full verb+scope statement, but the read intent is 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?

"One API campaign by id" implies the single-record fetch versus the list sibling, but the description never names aisensy_list_api_campaigns or says when to prefer one over the other. Usage is inferable rather than stated.

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