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

Annotations already declare destructiveHint=true and openWorldHint=true, but the description adds genuinely non-redundant behavior: the inbox contents are destroyed along with it, and live webhook deliveries to it begin failing. It also discloses the cost profile ('API calls: 1'). Return payload details are omitted, but an output schema exists to cover that.

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 short sentences, front-loaded with the action, then the consequence, then the cost signal. No redundant restatement of the tool name or schema fields.

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 one-parameter tool with annotations and an output schema, the description covers the essentials: what is destroyed, the downstream webhook breakage, and the call cost. Only the explicit alternative-routing guidance to clear_webhook_inbox 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 description coverage is 100% and the single 'id' parameter is documented in the schema, including where to obtain it (create_webhook_inbox or list_webhook_inboxes). The description adds nothing about the parameter, 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 ('Delete a test inbox') plus the scope of what is removed ('and what it holds'), which distinguishes it from clear_webhook_inbox (empties) and delete_webhook (removes the subscription, not the inbox). An agent can tell what this tool does 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?

Gives clear context for use and a concrete follow-up rule: if a webhook still points at the inbox, it will start failing and must be updated or deleted. It does not explicitly state when to prefer clear_webhook_inbox over deletion, so routing between the two emptying/removal siblings remains inferred.

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