Email across the account's applications

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

The readOnlyHint already indicates a safe read operation, and the description adds useful context about credential-dependent scope and what data is surfaced, including applications with no email. It does not describe pagination or exact response formatting, but it substantially enriches the behavioral picture.

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 description is compact and front-loads the account-wide email overview. The parenthetical field list is dense but informative, and the second sentence carries necessary credential-scope information.

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 input parameters and no output schema, the description does a good job explaining the returned information and the key credential-dependent scope difference. Some details such as pagination or exact response shape are omitted, but the core context is present.

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?

There are no input parameters, so the baseline is 4. The description adds only implicit context about account token versus project key authentication, but there are no parameter semantics to clarify.

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 clearly states that this is an account-wide email overview across every application, including state, pausing actor, recent sends versus allowance, deliverability, and applications with no email. It distinguishes the account-wide scope from single-application views implicitly, though it does not explicitly name any sibling tool.

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 explains the credential-dependent scope: with an account token it covers every application, and with only a project key it shows this application alone. However, it does not explicitly say when to use this versus alternatives such as email_status, email_activity, or email_deliverability.

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