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

With annotations already declaring destructiveHint=true and idempotentHint=true, the description still adds substantial context: auth requirement, that only one account-wide row is removed, the success payload ('deleted true'), the failure taxonomy (400 invalid_address, 404 suppression_not_found, 403 permission_denied for inbox-scoped keys), and an unusual inbox-scoped-key limitation. Nothing here contradicts 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?

Front-loaded with the usage trigger, then inputs, then return, then errors — a sensible ordering with little waste. The closing sentence about sending to a still-suppressed address describes a sibling tool's behavior and is mildly tangential, keeping it from a 5.

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?

There is no output schema, so the description carries the return contract itself ('returns the suppression with deleted true') and the complete error surface, which is exactly what an agent needs to call and interpret this destructive tool correctly. 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?

Schema description coverage is 100% and the single parameter is fully documented in the schema as an email address to remove. The description's 'Inputs: address (required; email)' merely restates that, adding no format, normalization, or casing detail — baseline 3 is appropriate.

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 ('Deletes that one account-wide row' of the suppression list) plus the scenario that motivates it (an address should receive mail again). An agent can distinguish this from cooper_list_suppressions and from the send/reply tools without opening a schema, and the account-wide scope is called out explicitly.

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?

Explicitly gives the trigger condition — use it when a previously suppressed address should receive mail again — and even enumerates the suppression causes (bounce, complaint, manual add). It lacks a when-not / alternative clause (e.g. pointing at cooper_list_suppressions to inspect before deleting), so it stops short of a 5.

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