Contacts Resolve Message Recipient

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the agent knows this is a safe, non-mutating lookup. The description adds no behavioral detail beyond what the annotations provide, and there is no contradiction. Baseline of 3 is appropriate because the description contributes nothing extra but annotations cover the safety profile.

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 short but not informative; it is essentially one sentence that restates the tool name. While brevity is present, it earns no credit because the structure lacks substance—there is no meaningful content to be concise about.

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?

Despite having an output schema, the input semantics are entirely opaque. The tool's purpose, query format, channel options, and relationship to sibling contact tools are all unexplained. An agent would likely misuse the 'query' parameter or confuse this with contact search tools.

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 description coverage is 0% and the description gives no meaning for 'query' or 'channel'. It does not explain what format 'query' should take (contact name? phone number? email?), nor what values 'channel' accepts (phone/email?) or its default behavior. With a default of 'phone' and no enums, the agent receives no assistance beyond the raw schema field names.

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 is a tautology: it repeats the tool name and states it is an exposed Apple domain tool, but does not explain what 'resolve message recipient' actually does. It fails to convey the operational purpose (e.g., mapping a query to a contact/recipient address for messaging).

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?

No guidance on when to use this tool vs alternatives like contacts_search_contacts or apple_suggest_contacts. The description does not clarify the context in which recipient resolution is needed, nor does it exclude cases where other contact-lookup tools would be more appropriate.

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