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

Annotations already declare a non-read-only, open-world, non-idempotent write; the description adds real value beyond them by flagging outbound side effects, the mandatory confirmation gate, and that the signing secret is returned only once. That is exactly the behavioral context an agent needs before invoking an externally visible write.

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 tight sentences with zero filler; the confirmation requirement is front-loaded right after the purpose statement.

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?

No output schema exists, and the description usefully discloses the one notable return value (the signing secret, delivered once). Combined with the confirmation protocol this is largely complete, though it omits error/failure behavior for an outbound-integration write.

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 only 17%, but the description compensates by naming the four fields the agent must surface for confirmation (URL, workspace, events, active state). It says nothing about the 'description' field, enum event values, or defaults, so meaning is only partly filled in.

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 ('Create a webhook subscription') and scopes it to post/account/analytics events, which is enough to separate it from list_webhooks. It does not explicitly say how it differs from the sibling manage_webhook, so the agent must infer that manage_webhook handles updates/deletes.

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 a concrete pre-call procedure: show target URL, workspace, events and active state, then obtain explicit confirmation. That is clear usage context, though it never names an alternative tool or states when not to create a webhook (e.g. when one already exists).

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