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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds a genuinely new behavioral fact not in any structured field: the Pro plan requirement, which can cause the call to fail or return nothing.

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 sentences, front-loaded with the verb and resource, then the field list, then the plan constraint. The field enumeration is dense but every item earns its place by substituting for the missing output schema.

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 carries the burden of describing return content and does so field by field, and it also discloses the plan prerequisite. Nothing an agent needs to select and invoke this 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?

Schema coverage is 100% and the single website_id parameter already documents its source (list_websites) and the omit-for-primary-website default. The description only reinforces that one site's settings are returned, which is marginal added meaning over 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?

"Show one website's AI email reply settings" gives a specific read verb plus a precisely scoped resource, and the enumeration (on/off, drafts vs automatic, delay, rules, alert and forwarding addresses) tells the agent exactly what data comes back. The read verb contrasts implicitly and cleanly with the sibling update_email_settings.

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?

The description supplies real usage context: it applies to a single website and requires the Pro plan or higher, which lets an agent rule it out for free-tier accounts. It does not explicitly route to update_email_settings for changes, so a small inference is left to the agent.

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