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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does not state that the operation is read-only, whether it returns actual credentials or just indicates their presence, or any potential side effects or limitations. Exposing SMTP credentials is a sensitive behavior that is not addressed.

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 a single, concise sentence that is front-loaded with the action and resource. It contains no unnecessary words or repetition, making it highly efficient.

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?

While the tool is simple with one optional parameter and no output schema, the description lacks essential context about return values and what 'managed' means relative to the sibling list_email_accounts. It does not specify whether it returns full credentials or just account metadata, leaving a completeness gap.

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 schema already provides 100% coverage for the sole parameter 'domain' with a clear description ('Filter by domain'). The tool description merely restates this ('optionally filtered by domain') without adding extra meaning, so the baseline of 3 applies.

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 the tool lists all email accounts with SMTP credentials, which is a specific verb+resource+scope. It inherently distinguishes itself from the sibling list_email_accounts by adding the qualifier 'with SMTP credentials', giving it a clear purpose.

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 implies when to use the tool (when you need email accounts with SMTP credentials or filtered by domain) but does not explicitly mention alternatives or exclusions. The sibling list_email_accounts exists but no guidance is given on which to choose, so usage is only implied.

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