Add or remove a mailbox alias

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

Annotations already declare destructiveHint=true and readOnly=false, so the mutating nature is covered. The description adds useful behavioral context beyond annotations: the operation returns the updated subscription and explains that the alias delivers into the mailbox. It doesn't discuss irreversibility, but that is reasonably implied by the remove action.

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 sentences with no filler. The core operation is front-loaded, the sibling alternative is clearly identified, and the id source is given last without redundancy.

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 output schema exists, the description covers all necessary decision points: what action this tool performs, when to choose this over the catch-all sibling, what it returns, and where to obtain the subscription id. No meaningful gap remains.

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 input schema already provides full descriptions for all three parameters, including the enum for action and a concrete example for alias. The description adds only mild value by reinforcing where the subscription id comes from and clarifying the alias purpose, so the baseline 3 applies.

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: add or remove a mailbox alias, and explicitly distinguishes this from eurodns_email_set_catchall. The action parameter is directly reflected in the description, leaving no ambiguity.

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?

Provides explicit guidance on when to use this tool ('named extra address') and names the alternative for catch-all usage. It also tells the agent where to get the subscription id, eliminating a prerequisite lookup.

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