list_contacts

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states it 'lists' contacts, implying a read-only operation, but does not explicitly mention any side effects, default ordering, pagination behavior beyond what the parameters suggest, or response format. The description adds minimal behavioral context beyond what is obvious from the name and parameters.

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 a single, focused sentence that front-loads the primary purpose ('List SMS Center address-book contacts') followed by a concise mention of optional parameters. There is zero waste, and it is appropriately structured for quick agent comprehension.

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 list tool with three well-documented parameters and no output schema, the description is largely complete. It explains what the tool does and mentions the optional filters/pagination. It does not explicitly describe the return format, but that is not required given the absence of an output schema and the straightforward nature of a list operation. It could benefit from a note about default behavior or sorting, but nothing critical is missing.

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 100% – each parameter (limit, offset, search) already has a description in the schema. The description merely repeats 'Optional search, limit, offset' without adding new meaning or clarifying syntax, defaults, or interactions. Since the schema does the heavy lifting, the description adds little value beyond the baseline.

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 clearly states the verb 'List' and the resource 'SMS Center address-book contacts', making the purpose unambiguous. It also mentions the optional parameters (search, limit, offset), and the resource 'contacts' distinguishes it from sibling tools like list_contact_lists or list_messages.

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 description implies when to use it (when you need to list contacts) but does not explicitly mention when not to use it or point to alternatives. There is no exclusion or comparison to siblings, but the resource is clear enough that an agent would understand the basic context. It lacks explicit guidance on choosing this over related list tools, but it is not misleading.

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