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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds real behavioral value by saying the pause is immediate and stops queueing new sends (implying in-flight sends may still go out), but it omits reversibility and 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?

One front-loaded sentence with the action verb first and the consequence second; no filler, no restatement of the title, nothing that could be cut.

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 single-parameter mutation tool with full annotation coverage and no output schema, the description supplies the essential purpose and effect. What is missing (in-flight send behavior, reversibility, the campaign_id requirement) is minor but non-zero.

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 0% and the single required parameter campaign_id is never mentioned in the description. The name is fairly self-descriptive, but with zero schema documentation the description does nothing to compensate for the gap.

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 and resource ('Pause a running campaign') and adds the operational effect ('stops queueing new sends'). It is clearly distinguishable from siblings like resume_campaign or get_campaign by the verb alone, though it never names an alternative 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?

The clause 'so it stops queueing new sends' implies the situation in which to call it, but there is no explicit when/when-not guidance and no routing to the obvious counterpart (resume_campaign) or any prerequisite. 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.