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

The annotations already establish that this is a read-only, idempotent, non-destructive operation. The description adds useful behavioral context beyond them: certain transactional emails are deliberately omitted because they cannot be switched off. With an output schema present, return-value details need not be repeated.

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 definition is two tight sentences, front-loaded with what the tool lists and followed by a useful exclusion. Every sentence carries information relevant to selecting or interpreting the tool.

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?

For a zero-parameter read tool with full annotations and an output schema, the description is largely complete. The only minor gap is that it does not explicitly point to set_notification for making changes, though the read-only framing makes that reasonably inferable.

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?

This tool takes zero parameters, so there is no parameter semantics to explain and the baseline is 4. The description does not need to compensate for any schema coverage gap.

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 uses a specific verb ('List') and resource ('kinds of email Postmoderno sends about your work and whether each is switched on'), making the read operation clear. It also scopes out transactional emails, but it does not explicitly name the sibling write tool (set_notification) for changing 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 phrase 'For questions about what the user is emailed about' gives a clear usage context, and the exclusion of confirmation codes, reset links, and invite links clarifies one case where the tool should not be expected to help. However, it does not explicitly direct the agent to set_notification when the user wants to change a setting.

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