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

Annotations already cover the safety profile (idempotentHint=true, destructiveHint=false, openWorldHint=true), but the description adds materially more: the idempotency is explained concretely (same `url` returns the same id, retries never create duplicates), the `secret` lifecycle is disclosed (generated and returned exactly once, never retrievable again), and the `X-Reqbeat-Signature` header is named. The free-vs-billed note is extra operational context the annotations cannot express.

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?

The purpose and the 'call this first' ordering are front-loaded, which is exactly right. The second sentence, however, chains three distinct concerns (idempotency, secret lifecycle, billing) into one long dash- and parenthesis-heavy clause, which slightly hurts scannability even though every clause is informative.

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?

There is no output schema, so the description must and does describe returns (`webhook_endpoint_id`, the one-time `secret`). Combined with the ordering rule, idempotency guarantee, and signature header, an agent has everything needed to call this correctly on the first attempt.

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?

With only 33% schema description coverage, the description carries most of the load: `url` is framed as a delivery target and `secret` is explained as optional, its verification role stated, and its one-time return behavior described. The only gap is `plane_api_key`, which the description ignores entirely, though the schema itself flags it as deprecated in favor of the header.

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 a specific verb and resource ('Register the delivery target a watch fires to') and immediately names the artifact produced (`webhook_endpoint_id`). It clearly distinguishes itself from the sibling `watch_company`, which is the consumer of that id rather than a competitor for the same action.

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?

It gives an explicit precondition and ordering rule: 'call this first if you do not already hold one.' It also explains the relationship to the follow-up tool and even the billing consequence of the subsequent `watch_company` call, so an agent knows both when and why to reach for it.

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