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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the bar for additional disclosure is lower. The description still adds meaningful detail by stating that the inbox's entire history is destroyed, not just the inbox record itself. It does not cover error behavior when the id does not exist, even though the annotations imply that repeated calls are idempotent.

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?

One short sentence with no filler, and the permanence warning is front-loaded ahead of the resource. Every word earns its place, with no redundancy or structural confusion.

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 destructive, irreversible tool with no output schema, the definition is adequate but thin: it does not describe success/failure responses or what happens to dependent webhook deliveries. The schema fully documents both parameters, which offsets part of the gap. An agent can call it correctly, but must rely on annotations for the safety profile.

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%, with both the resource UUID and the optional management/inspection token fully documented in the schema. The description adds no semantics beyond that, such as what happens if a token is supplied for a workspace-owned resource. When the schema already does the heavy lifting, a 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?

The description pairs a specific verb ("Permanently delete") with a specific resource ("an inbox and its history"), so the operation is unambiguous. It also makes clear the target is a webhook inbox rather than an email inbox through the tool name. It stops short of naming sibling tools, but the verb/resource pair already separates it from create_webhook_inbox and inspect_webhook_inbox.

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?

The word "Permanently" signals that this is an irreversible action, which is a weak usage cue. The description never says when to choose this tool over inspect_webhook_inbox first, which prerequisites apply, or whether a token-authenticated anonymous inbox behaves differently. An agent gets no explicit routing or precondition guidance.

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