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

Annotations already mark destructiveHint=true, so deletion is known. The description adds value by specifying what gets stopped ('future realtime delivery') and requiring explicit user intent, which is a meaningful behavioral caution. It does not mention irreversibility or permission needs, but the annotation plus consequence statement carry most of the burden.

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?

Two tightly written sentences: the first states the action and scope; the second states the direct consequence and a safety requirement. There is no filler or repetition of schema content.

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 single-parameter deletion tool with full schema coverage and annotations, the description is complete. It names the resource, the effect, and the user-intent requirement; nothing an agent needs to decide whether to invoke it 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 destination_id property is already well documented: it is the Nilyo webhook destination ID returned by create/list tools and must never be the Unipile endpoint ID directly. The description adds no new parameter-level detail, so the 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 states the exact action ('Delete') on a specific resource ('Nilyo-owned Unipile webhook endpoint') and names the ownership boundary, which distinguishes this from deleting some other webhook resource. It clearly differentiates from sibling tools like webhook_create_destination, webhook_update_destination, and webhook_list_destinations.

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 description tells the agent the consequence ('stops future realtime delivery to that destination') and adds an important gate: 'require explicit user intent.' It does not explicitly contrast with alternatives (e.g., updating/disabling instead of deleting), but the direct deletion call and consequence make the usage context clear.

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