list_signatures

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

With no annotations, the description carries the behavioral disclosure burden. 'List' implies a read-only operation and the 'Scope: signature:read' line adds useful permission context. However, it does not describe return format, ordering, empty-list behavior, or error cases, leaving some behavior implicit.

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 short sentences contain only necessary information. 'List mail signatures' is front-loaded and 'Scope: signature:read' adds a relevant permission detail without wasting words.

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 list operation, this is nearly complete: it states the action, resource, and required scope. It omits the return shape, but the verb 'List' strongly implies a collection, and the absence of an output schema lowers the burden.

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 input schema is empty, so schema coverage is 100%. The description correctly does not need to explain parameter semantics; the baseline for a no-parameter tool 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 uses a specific verb ('List') and identifies the exact resource ('mail signatures'), making the operation unambiguous. It also distinguishes itself from sibling list_* tools such as list_mailboxes, list_labels, and list_mails by the resource name.

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 intended use case is clear from the resource name and verb, and there are no exclusions. It does not explicitly name alternatives like list_mailboxes or list_labels, but since each sibling operates on a different resource, the differentiation is obvious without further guidance.

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