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

Annotations already declare destructiveHint=true and idempotentHint=true; the description adds valuable context beyond them by clarifying the operation is a reversible pause ('Contacts keep their place in the sequence') and that a resume path exists. It does not say whether an already-paused campaign errors or no-ops despite the idempotent hint, leaving one behavioral gap.

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, with the core action and effect front-loaded and the recovery path trailing. 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 no output schema, the description covers the action, the side effect on contacts, and the reversal route, which is enough for correct invocation. Only the edge case of deactivating an already-paused campaign is left unaddressed.

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?

There is a single parameter with 100% schema description coverage ('Campaign UUID - get from list_campaigns'), so the schema already carries the semantics. The description adds no parameter detail, which is the baseline 3 expectation when the schema does the heavy lifting.

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?

Specific verb+resource ('Deactivate (pause) a campaign') with the effect stated ('stops sending'), and it explicitly distinguishes itself from the sibling activate_campaign. An agent can immediately tell this apart from complete_campaign or update_* siblings.

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 gives a clear condition for use (to stop sending) and names the counterpart tool for the reverse action ('resume with activate_campaign'), which effectively routes the agent. It does not state when NOT to use it (e.g., vs complete_campaign, which is terminal), so it falls short of a full 5.

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