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

Annotations already declare readOnly, idempotent and non-destructive behavior, so the safety profile is covered. Beyond that, the description adds genuinely useful behavioral context: the auth requirement (edm_ token or session) and critically the 24-hour grace period where the previous secret continues to sign after rotation, including the observable two-part 'v1,' header. That is non-obvious operational behavior the agent could not get from structured fields.

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 owner-state information is front-loaded, which is good, but the description then spills into detailed HMAC/base64/Standard-Webhooks implementation notes and a 5-minute timestamp-rejection rule that are tangential to retrieving owner state. These earn little or nothing for an agent deciding to call get_owner and bloat an otherwise short tool definition.

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 and no parameters, the description carries the burden of explaining what is returned, and it does list the returned fields (account/guest type, notice e-mail, allowance, signing secret) plus the auth requirement and rotation grace behavior. An agent has enough to call it correctly; only the exact response shape remains loosely specified.

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 the baseline of 4 applies. There is no parameter surface for the description to compensate for.

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 clause identifies the resource (owner state) and lists the fields it carries (account/guest, notice e-mail, allowance, secret). However, the bulk of the description is about webhook signature verification rather than the tool's own purpose, and it never distinguishes itself from siblings like create_owner or rotate_webhook_secret. The core verb is implied rather than stated ('The owner state...' rather than 'Returns the owner state').

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?

There is a stated prerequisite (requires the edm_ token or account session), but no when-to-use guidance, no exclusions, and no routing to alternatives such as rotate_webhook_secret when the secret needs changing. Usage must be inferred from the tool name.

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