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

The description adds substantial context beyond the destructiveHint annotation: unsent mail is stopped, no properties can be added, the campaign can never be resumed, already printed/carrier mail still delivers, drafts are excluded, and the user must be warned. This is exactly the kind of consequence disclosure a destructive tool needs.

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?

The description is front-loaded with the core action and is dense with useful caveats. Some points (permanent, cannot resume, cannot be undone) are slightly repetitive, but no sentence is wasted.

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?

Given the destructive nature and the annotation set, most behavioral consequences and state exclusions are covered. The two notable gaps are disambiguation from the cancel sibling and guidance on obtaining the campaign_id.

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 only 50%, and campaign_id has no schema description. The description does not explain where to obtain campaign_id or its expected format, and it only indirectly reinforces the confirmed flag via a user warning. Little parameter-level meaning is added beyond 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 description states a specific verb ('Ends') and resource ('mail campaign') with clear scope ('permanently') and applicable states ('Ready, Active or Paused'). It distinguishes itself from non-terminal operations like pause/resume without needing to open a 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?

It clearly states when to use (Ready/Active/Paused campaigns) and when not to use (drafts cannot be ended), and it directs reuse via a new campaign. However, it never mentions the sibling 'dealmachine_mail_campaign_cancel', leaving the agent to infer the distinction between ending and cancelling.

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