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 largely covered. The description earns credit by disclosing a non-obvious side effect the annotations do not convey: all currently scheduled emails are cancelled, not merely deferred. It does not say whether those cancelled sends can be recovered, which leaves a mild tension with destructiveHint=false, but the core behavior is surfaced.

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?

A single sentence with the action front-loaded and the consequential side effect immediately after it. Nothing is wasted and nothing important is buried.

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 no output schema and annotations covering idempotency and safety, the description covers the essential action and its main side effect. It could have stated the error condition when the campaign is not running and whether pausing is reversible, but the gaps are minor.

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 one parameter and 100% schema description coverage, the schema already explains the id fully, including its source ('from list_campaigns'). The description adds no further meaning 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?

The description uses a specific verb and resource ('Pauses a running campaign') and adds the key side effect ('cancels all currently scheduled emails'), which distinguishes it in spirit from delete_campaign. It stops short of naming any sibling explicitly, so the differentiation is inferred rather than stated.

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?

There is no when-to-use guidance, no statement of the precondition that the campaign must currently be running, and no pointer to how a paused campaign is resumed (e.g., launch_campaign) or why one would pause rather than delete. Usage is only implied by the word 'running'.

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