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

Annotations already indicate this is a mutating operation (readOnlyHint=false). The description adds valuable behavioral context beyond that: 'stop' is permanent and cannot be resumed, and user confirmation is required. This addresses the most important side effect an agent needs to know. No contradiction with annotations is present.

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?

The description is two sentences with no wasted words. The core function is stated first, followed by the critical warning about permanence and confirmation. It is well-structured and easy to parse.

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 simple three-parameter mutation tool, the description covers the essential behavior, the permanent nature of 'stop', and the confirmation requirement. The schema fully documents all parameters, and the description adds the key caveat. A return-value description would be nice but is not essential for correct invocation.

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 coverage is 100%, so the baseline is 3. The description adds meaningful semantics beyond the schema by explaining that 'stop' is permanent and that confirmation is necessary before stopping. This directly enriches the meaning of the 'action' and 'confirm' parameters.

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 uses a specific verb ('Change the run state') with a clear resource ('campaign') and enumerates the three possible actions: pause, resume, and stop. This clearly distinguishes it from sibling tools like create_campaign or get_campaign_stats, which handle different lifecycle stages.

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 clearly indicates this tool is for changing a campaign's run state, and provides explicit guidance to confirm with the user before using 'stop' because it is permanent. It does not explicitly name alternative tools or state when not to use it, but the context is clear enough for an agent to select it appropriately.

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