Enable or disable the catch-all of a mailbox

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

Annotations already flag readOnlyHint=false, idempotentHint=true, and destructiveHint=true; the description adds meaningful behavioral context by explaining that enabling routes addresses without a mailbox/alias to this subscription and may attract unsolicited mail, while disabling refuses such mail. It does not contradict the annotations.

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?

Four sentences, front-loaded with the primary action and return value, followed by behavioral effect, alternative, and id source. Slightly wordy and awkward in the middle sentence, but no wasted sentences.

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?

Together with the complete input schema and output schema, the description gives enough context to select and call the tool correctly: action, routing behavior, alternative tool, and source of the id. It does not need to explain return shape because output schema exists.

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% and the schema already documents id as the numeric email subscription id from eurodns_subscription_get and enabled as true/false behavior. The description mostly restates these semantics rather than adding new parameter-level meaning.

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 action (turns catch-all on/off) on a specific resource (email subscription id), describes the returned updated subscription, and distinguishes itself from the sibling eurodns_email_set_alias by naming the alternative for named addresses.

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 when-to-use context for enabling/disabling the catch-all and an explicit exclusion: use eurodns_email_set_alias for a single named address. It also tells the caller where the subscription id comes from via eurodns_subscription_get.

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