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

Annotations only declare the safety flags (not read-only, not destructive, not idempotent); the description adds the actual state semantics an agent needs — writing halts, but existing posts retain their calendar slots. That 'what is preserved' detail is exactly the kind of context annotations cannot convey. It omits whether the pause is reversible via start_campaign and what the response reports, keeping it at 4.

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, no filler, and the core effect is front-loaded ahead of the caveat about existing posts. Every clause carries information.

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 one-parameter mutation with annotations covering the safety profile and no output schema, the description covers the essential behavioral question: what happens to scheduled posts. It leaves open whether the campaign can be resumed and what the call returns, which are minor for a simple pause action.

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?

Only one parameter and schema coverage is 100%, with the schema already stating 'by id or by name.' The description adds nothing about the identifier, so the baseline of 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 verb and resource with the precise effect: 'Stops a campaign writing any more posts.' That phrasing separates it from delete_campaign and cancel_campaign_posts without naming them. It stops short of an explicit sibling contrast, so a 4 rather than a 5.

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 second sentence tells the agent the condition under which this tool is the wrong choice for the leftover posts: 'cancel them individually if they should not go out,' which implies the cancel_campaign_posts path. Clear usage context, but the alternative tool is never named and there is no guidance on when to pause versus stop or delete a campaign.

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