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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint, so safety is covered. The description adds genuine business context that annotations cannot convey: the result carries status and template, and only LIVE campaigns are sendable. It does not describe pagination, result size, or what statuses other than LIVE look like.

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?

Three short sentences, front-loaded with the purpose before the precondition and the endpoint. The trailing 'GET /project/{project_id}/campaign/api' is marginally useful for API-oriented agents but is the weakest sentence of the three.

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 0-parameter, non-destructive list tool with no output schema, the description supplies enough: what is listed, what fields come back (status, template), and the business rule that gates sending. Missing only return volume/pagination detail, which is minor here.

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?

The tool takes zero parameters, so there is no parameter semantics to explain; the schema is empty and fully described. Baseline for a 0-param tool is 4, and nothing in the description contradicts 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?

States a specific verb and resource ('List the project's API campaigns') and parenthetically defines what an API campaign is — one that messages can actually be sent through — which separates it from the general aisensy_list_campaigns. It never names that sibling outright, so the differentiation must be inferred from the parenthetical rather than being explicit.

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?

'A campaign must be LIVE to send' implies the usage context (call this to find a sendable campaign before send_campaign_message), but the connection is left implicit — no tool names an alternative or states when not to use this. The guidance is present but requires the agent to join the dots.

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