schedule_campaign

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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=true, so the mutation profile is structured. The description adds genuine value by clarifying the deferred, non-immediate effect, but it never addresses what makes this 'destructive' — e.g. whether an existing scheduled send is overwritten — nor any preconditions such as the campaign having to exist or be unsent. With annotations carrying the safety profile, a 3 is appropriate.

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 action and scope, then the disambiguation. No filler and no restatement of the name.

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 2-parameter tool with full schema coverage, annotations, and no output schema, this covers the essentials: what happens, when to use it, and what not to confuse it with. The remaining gaps are preconditions and state effects (draft-only, overwriting an existing schedule, behavior for past timestamps), which an agent would still have to discover.

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%: send_at is documented with ISO 8601 + timezone and a concrete example, and campaign_id with its type. The description only adds the constraint that the time must be in the future, which is marginal but real value. Baseline 3 is correct 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?

States a specific verb and resource ('Schedule a campaign') plus the outcome semantics ('start sending automatically at a future date and time'), which an agent can map to a distinct operation. It explicitly contrasts with the sibling send_campaign, so the tool is separable from alternatives without opening any schema.

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 the selecting condition ('future date and time') and names the explicit alternative with its own condition ('Use send_campaign to send immediately instead'). The clarification 'Nothing is sent now' eliminates the main ambiguity an agent would have between the two tools.

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