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

Adds substantial context beyond the annotations: the enumerated launch_blockers that cause refusal, the async 202 response with a one-time operator approval gate, and the required scope. Annotations only say idempotent/non-destructive; the description explains failure modes, auth, and async behavior the annotations do not cover.

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 tight sentences: action first, then blockers/precondition, then approval behavior and scope. No filler, and the primary verb is front-loaded.

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?

No output schema exists, and the description compensates by describing the return behavior (202 with pending approval) and refusal signals. Combined with annotations and full schema coverage, an agent has everything needed to call it correctly.

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 both campaign_id and idempotency_key are already documented in the schema, including the retry semantics. The description adds nothing about parameter format or constraints, so the baseline 3 is appropriate.

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 ('Start a draft campaign') and implicitly scopes it to drafts, which separates it from create_campaign, simulate_campaign, pause_campaign, and resume_campaign in the sibling list. An agent reading only the first sentence knows exactly what this does.

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?

Gives clear operating context: it works on a draft, requires the manage_campaigns scope, and needs specific blockers resolved first. It does not explicitly name an alternative or exclusion (e.g., when to prefer simulate_campaign first), so it stops short of a 5.

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