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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds value beyond them: the required OAuth scope (webhooks:write), the fact that a queued delivery can be canceled but an in-flight HTTPS request cannot be recalled, and that buyer/order state changes. This is meaningful context, though it does not explain response behavior for idempotent re-calls.

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, front-loaded sentences with no filler; the primary effect comes first, followed by caveats and auth requirements. Every sentence carries actionable information.

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 one-parameter destructive tool, the description covers authorization scope, irreversible/in-flight limitations, and state side effects, and an output schema exists so return values need not be explained. Nothing an agent needs to invoke it correctly 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%, so the single subscription_id parameter is already fully documented, including its format, source, and explicit non-equivalences (not a delivery ID or signing secret). The description adds nothing parameter-specific, 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 ('Revoke an owned order event subscription') plus the secondary effect (canceling queued deliveries). This clearly distinguishes it from sibling tools like create_webhook, list_webhooks, and list_webhook_deliveries.

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?

Usage is implied rather than stated: the word 'owned' plus the note that this affects 'buyer or order state' suggests the appropriate context. However, there is no explicit when-to-use/when-not guidance or direct routing to alternatives (e.g. use list_webhooks to find the ID, use this only to permanently revoke).

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