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

Annotations already flag destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the safety bar is lower, but the description still adds substantial behavior: cancellations of unsent mail, reservation release, reminder stoppage, hiding from default lists, and the nuance that already-submitted mail may still ship. The only missing piece is whether the archive can be reversed (unarchive), which would complete the risk picture for a destructive operation.

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?

Six short sentences, front-loaded with purpose and precondition, then consequences, then the confirmation instruction. Every sentence carries distinct information — no filler and no repetition of the annotations.

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 two-parameter destructive mutation with no output schema, the description supplies the prerequisite state, the error contract, the side effects, data-retention behavior, and the user-confirmation requirement. Nothing an agent needs to call this safely is missing.

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 50% — the 'confirmed' parameter is fully documented in the schema, and campaign_id has no description in either place. The description reinforces the confirmation semantics ('Confirm with the user first') but adds nothing about campaign_id formatting or where to obtain it. Baseline 3 is right given the partial coverage.

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 opens with a specific verb and resource ('Archives an ended campaign') and immediately narrows scope to ended campaigns, which distinguishes it from siblings like dealmachine_mail_campaign_end or dealmachine_mail_campaign_cancel. An agent knows exactly what state transition this performs without opening the 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 states the precondition explicitly ('End active, paused, ready or draft campaigns first'), names the exact failure mode if violated (409 CAMPAIGN_NOT_ENDED with no change), and adds a procedural gate ('Confirm with the user first'). That covers when to use it, when not to, and what to do instead.

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