list-smart-mailboxes

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

With no annotations provided, the description carries the full burden. It discloses a non-obvious behavioral trait (German-localized macOS compilation issue) and states the output format (name and criteria summary). While it does not explicitly say 'read-only' or mention error conditions, the listing operation is inherently safe and the additional context is valuable.

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 well-structured, with distinct 'Use when', 'Returns', and 'Do not use when' sections. Every sentence earns its place and there is no wasted text.

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 tool with an output schema, the description fully covers purpose, usage boundaries, a subtle locale-specific pitfall, and return content. Nothing critical is missing; the sibling differentiation completes the context.

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 zero parameters and the schema is already complete (100% coverage, no properties). The baseline for 0 params is 4, and the description adds no misleading or redundant parameter info, so this score is appropriate.

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+resource ('listing Apple Mail smart mailboxes') and clearly distinguishes this tool from listing real folders by naming the sibling tool 'list-mailboxes' in the negative case. It also adds a useful differentiating detail about German-localized macOS support.

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?

Explicit 'Use when:' and 'Do not use when:' sections provide direct guidance on when to select this tool versus the alternative, even naming the specific sibling tool. This is the clearest possible usage guidance.

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