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

Beyond the annotations, it discloses substantial behavior: the token is shown only once with no recovery, it is rate-limited per network and per hour, the webhook secret can be re-read and rotated with a 24h dual-signature grace period, and it even specifies the webhook signature scheme and timestamp window. This is rich operational context well past what readOnlyHint/idempotentHint convey.

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?

Purpose is front-loaded, but the text is bloated: the HMAC-SHA256 construction of 'id.timestamp.corpo', the 5-minute timestamp rejection rule, and the Standard Webhooks library reference are receiver-side verification instructions, not guidance for invoking this tool. Much of the length does not earn its place for tool selection.

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 no output schema, the description must explain the return artifacts, and it does: the 'edm_…' bearer token and the 'whsec_…' secret, including where the token goes (Authorization: Bearer) and how the secret is later retrieved. Nothing needed to call 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate. The baseline for a no-parameter tool is 4, and the description correctly explains the artifact returned rather than inventing parameter details.

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 opening states a concrete verb and resource: it creates the guest owner credential — the 'edm_…' token that unlocks alerts and watches plus the 'whsec_…' webhook signing secret. This clearly maps to the criar_/dono family, though it never explicitly names which sibling to pick instead (e.g. dono, rotacionar_segredo_webhook).

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 signals the context ('Sem cadastro') and advises storing the one-time token and later claiming lists via the account page so you don't depend on it. However, it never states explicitly when to choose this over siblings like dono (read) or rotacionar_segredo_webhook (rotate); usage is implied rather than routed.

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