apple_contacts_update

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

Annotations already declare destructiveHint=true, idempotentHint=true, openWorldHint=true and readOnlyHint=false. The description adds genuinely new context on top: which field collections are preserved (phone/email) and that the call refuses while unsaved Contacts edits are pending. That state-dependent refusal is the kind of behavior annotations cannot express.

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?

Three short sentences, no filler, with the scope of the write front-loaded and the constraints (unchanged collections, refusal condition) following immediately. Every sentence carries distinct information.

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?

No output schema exists, so the description is not obliged to describe returns, and the mutation/precondition facts are present. Still missing for a 6-param update tool: where contactId comes from, and confirmation that unmentioned fields beyond phone/email are left untouched. Adequate but with visible gaps.

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%, so the description carries the burden, and it names four of the five payload fields (name covering firstName/lastName, organization, jobTitle, note). The required contactId is never explained — no hint on format or how to obtain it — and there is no statement of what happens to omitted optional fields. Partial compensation only.

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 gives a specific verb+resource ('Update and save selected name, organization, job title, or note fields') and enumerates exactly which fields are in scope, so an agent knows this is a contact-field mutation rather than a general contact write. It never names a sibling tool (e.g. apple_contacts_create or apple_contacts_get) to route against, which keeps it short of a 5.

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?

'Refuses pending unsaved Contacts edits' is a useful precondition, and 'Leaves phone and email collections unchanged' delimits scope. However, there is no explicit when-to-use guidance versus alternatives (apple_contacts_create, apple_contacts_get) and no statement of what to do when the refusal fires. Usage is implied rather than stated.

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