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

Newest-first ordering and the product-scope limitation add behavioral context beyond the supplied annotations. However, "Read-only" largely repeats readOnlyHint, and the description does not explain cursor-based pagination or page 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 compact sentences front-load the resource, result metadata, and ordering, then state the write-operation boundary without padding. The terse phrases "Segment messaging campaigns" and "at launch" slightly reduce immediate clarity.

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?

The output schema and safety annotations reduce the description's burden, and the ordering and capability boundary are useful for this simple list operation. Nevertheless, the lack of any parameter documentation leaves status filtering and limit/cursor pagination underexplained.

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?

With 0% schema description coverage, the description needed to explain the three parameters but does not identify status as a results filter or describe how limit and cursor control pagination. Its references to status and ordering provide only slight contextual help.

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 identifies messaging campaigns as the resource and adds useful result characteristics: status and progress counts, ordered newest first. It is distinguishable from sibling list tools by resource, although the opening phrase "Segment messaging campaigns" is awkward and does not explicitly say "list."

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 explicitly rules out campaign creation and control and directs those actions to the inbox UI, providing useful when-not guidance and an alternative. Positive selection guidance, such as when to use this for campaign inspection or status filtering rather than reporting tools, remains implicit.

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