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

Annotations declare destructiveHint=true and openWorldHint=true, and the description adds real value beyond them: the 'never spends credits' cost note and an explanation of the consequences of changing URL (delivery target) and events (what gets sent). It stops short of clarifying irreversibility or that a new secret invalidates existing signature verification, which matters for a destructive mutation.

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-loads the action, then the cost note, then effects. Mostly tight, though the trailing clause ('and the results they carry') and the URL/event effect sentence lean toward restating the obvious.

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?

With an output schema present and full schema coverage, the description needs only the behavioral layer, and it largely provides it (cost, effect of changes). It could note irreversibility or secret rotation impact, but is otherwise sufficient to call correctly.

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 coverage is 100%, so the schema already documents all five parameters, including the private-address refusal for url and the minItems:1 constraint for events. The description only restates the effects of url/events changes, adding marginal meaning beyond the schema.

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?

Clear verb (Change) + resource (webhook settings) with the three updatable fields spelled out. 'Registered webhook' implies an existing resource, loosely distinguishing it from create_webhook, but no sibling is named 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?

Usage is implied by 'registered webhook' (you need an existing one, id from list_webhooks) and the cost note helps prioritization, but there is no explicit when/when-not guidance or routing against create_webhook/delete_webhook.

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