Resolve Contact

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

With no annotations, the description carries the behavioral burden. It does disclose partial-name matching and that phone numbers are returned, which is core behavior. But it leaves important traits unstated: whether it reads local device contacts, whether permissions are required, how duplicates or unmatched names are handled, and how limit/device affect results.

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 one concise sentence with no filler. The main action is front-loaded, and every phrase adds relevant information: 'contacts', 'partial name', and 'return their phone numbers'.

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 lookup tool with an output schema, the description is minimally adequate: it states what to pass and what comes back. However, with no annotations and no parameter descriptions, the missing semantics of 'limit' and 'device', plus no mention of no-match behavior, make it incomplete for robust autonomous use.

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 must compensate for the bare input schema. It adds meaning only to the 'name' parameter via 'partial'. It does not explain 'limit' or 'device', leaving their semantics to be guessed from their names and defaults.

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 names a specific action ('Find contacts'), a specific resource ('contacts'), a matching rule ('partial name'), and the return value ('phone numbers'). It also clearly distinguishes resolve_contact from sibling tools like resolve_deeplink because it names the exact subject matter.

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 use case is implied: use it when you need contact phone numbers from a partial or full name. However, the description gives no explicit when-to-use/when-not-to-use guidance, no mention of alternatives, and no prerequisites such as required permissions or device context.

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