apple_contacts_add_to_group

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

Annotations already declare this is a non-readonly, idempotent, non-destructive, open-world mutation, so the safety profile is covered. The description adds 'and save Contacts changes', clarifying that the change is persisted immediately with no separate save step. It does not cover failure modes such as a missing contact or group.

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 efficient sentence that front-loads the action and adds the persistence detail without any wasted 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 simple two-parameter mutation with annotations covering safety and no output schema, the description is adequate but leaves gaps: no mention of what happens on an invalid contactId or groupId, no idempotency restatement beyond annotations, and no parameter format detail.

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?

Schema coverage is 0%, so the two required parameters (contactId, groupId) have no structured documentation. The description only obliquely implies the parameters refer to a contact and a group, without specifying identifier format, whether names are accepted, or whether the group must pre-exist.

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 states a specific verb+resource pair ('add an existing contact to a group'), which is unambiguous and clearly distinct from the sibling apple_contacts_remove_from_group. It does not explicitly name siblings, but the action is self-evident from the name and text.

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?

There is no guidance on when to use this tool versus alternatives such as apple_contacts_update or apple_contacts_remove_from_group, and no stated prerequisites (e.g., that both the contact and group must already exist). The only implicit signal is 'existing contact'.

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