list_contacts

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

No annotations provided; description only says 'lists contacts', which implies a read operation but doesn't disclose scope, pagination, or any permissions. Insufficient for a tool with no annotations.

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?

Single sentence, no fluff, immediately clear. Front-loaded information. Every word earns its place.

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; description does not specify return format or whether all contacts are returned. For a listing tool with no parameters, some indication of completeness or ordering would help. Barely adequate.

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?

Input schema has 0 parameters with 100% coverage; baseline is 4. Description adds no parameter info but none is needed. Adequate for the parameter-less case.

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?

Description specifies verb 'lists' and resource 'contacts from macOS Contacts app', clearly distinguishing from m365_list_contacts or search_contacts. Unambiguous purpose.

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 vs alternatives. For example, doesn't mention that search_contacts should be used for searching; nor does it say if it returns all contacts unconditionally.

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