cancel_send

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

The description discloses that the action is irreversible, cannot recall delivered emails, and only succeeds if the campaign is currently sending. Annotations are all false, but the description adds essential behavioral context beyond them without contradiction.

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?

Concise and well-structured: a brief statement followed by bullet points for conditions, arguments, and return value. No unnecessary words.

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?

Despite output schema not displayed, the description mentions the return JSON structure. It covers constraints, prerequisites, and error conditions adequately for a cancellation tool.

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 description explains 'campaign_id' format and requirement, but does not cover the optional 'account' parameter. With 0% schema description coverage, the description partially compensates but leaves a gap.

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 description explicitly states the tool cancels a campaign mid-send, using a specific verb ('Cancel') and resource ('campaign'). It distinguishes from sibling 'unschedule_campaign' by noting it's for scheduled campaigns, not sending ones.

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?

Clear guidelines: only works on campaigns with status 'sending', and advises using 'unschedule_campaign' for scheduled campaigns. Explicitly states when to use and when not.

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