create_contact_group

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

No annotations are provided, so the description carries the full behavioral burden, and it discloses only the target account. It says nothing about whether macOS automation permission is required, what happens if a group with the same name already exists, whether the new group is empty, or what the call returns.

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?

A single front-loaded sentence with no filler; the parenthetical bundle name adds disambiguation rather than redundancy. Nothing could be removed without losing meaning.

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, zero-annotation, no-output-schema creation tool, the description covers the what and the where but omits duplicate-name behavior, permission requirements, and return value. It is minimally adequate rather than complete.

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 declares zero parameters, so there is no parameter semantics to explain; baseline 4 applies. The description correctly implies the operation is parameterless by not referencing any inputs.

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?

States a specific verb and resource (creates a group) plus the target system (Mac Contacts.app, default account), which separates it from the WhatsApp and M365 group-creation siblings. It stops short of naming any sibling explicitly, so differentiation is inferred from the app name rather than stated.

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 app and account scoping ('Mac's Contacts app ... in its default account') implicitly tells the agent this is the local-Contacts option versus the WhatsApp/M365 alternatives, but there is no explicit when-to-use or when-not-to-use statement and no prerequisites are mentioned.

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