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

Annotations already declare destructiveHint=true, openWorldHint=true and readOnlyHint=false, so the 'DESTRUCTIVE' framing mostly reinforces structured data. What the description genuinely adds beyond annotations is the confirmed=true consent gate, the DRAFT→SCHEDULED transition, the 409 SENDER_INELIGIBLE failure mode, and the AUTO_PAUSED downstream effect — real operational context, but the core safety signal duplicates the hints.

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?

Front-loaded with purpose, then the destructive warning, then prerequisites and failure modes — a sensible ordering with no filler. The closing sentence about a scheduled campaign being auto-paused later is useful but slightly off the main decision path, keeping it just short of maximal tightness.

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 3-parameter mutation tool with no output schema, the description covers success state (DRAFT→SCHEDULED), the consent gate, the main refusal path and its remedy, and the downstream paused state. Nothing an agent needs to call it safely and interpret the failure is missing.

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 earns above baseline by adding meaning the schema does not convey — that scheduled_time must be in the future and that confirmed=true represents explicit user consent rather than a mere boolean. It does not add new syntax beyond the ISO example already present in the schema.

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 opening sentence pairs a specific verb ('Schedule') with a specific resource ('existing DRAFT campaign') and a scoping condition ('ISO-8601 datetime'). Combined with the neighbor guidance to call nevent_get_campaign first and the implied contrast to nevent_create_campaign, an agent can place this tool precisely among the campaign 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 states the precondition (campaign must already exist in DRAFT), the mandatory prerequisite call (nevent_get_campaign to verify content and segment), the consent requirement, and the recovery path for the SENDER_INELIGIBLE refusal via nevent_get_sending_profile. That is explicit when-to-use plus named alternatives, not inference.

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