list_phone_numbers

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

No annotations are provided, so the description carries the burden of explaining behavior. It discloses that the tool returns a list of numbers with specific fields (ID, number, type, capabilities, status) and implies a read-only operation via the word 'List'. However, it does not mention potential pagination, rate limits, or any side effects, which leaves some behavioral ambiguity.

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 extremely concise, consisting of two sentences. The first sentence states the purpose, and the second explains the return fields and how to use the output. No unnecessary information is included, and it is front-loaded with the most important detail.

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?

Given the tool's simplicity (no parameters, output schema present), the description is complete. It clearly explains the purpose, what is returned, and how to use the result. The mention of 'provisioned' numbers effectively distinguishes it from similar listing tools, covering the necessary context.

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?

The tool has zero parameters, so the description does not need to explain input semantics. The baseline for zero parameters is 4, and the description adds meaningful output context by detailing the fields returned, which is useful beyond the empty schema.

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 tool's function: 'List all provisioned phone numbers in your Commune account.' It uses a specific verb ('List') and resource ('provisioned phone numbers'), and distinguishes itself from the sibling tool 'list_available_phone_numbers' by specifying 'provisioned' rather than 'available'.

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 provides clear context on when to use this tool by stating that the returned phone_number_id can be used with SMS tools or update_phone_number. It does not explicitly exclude alternatives, but the purpose is straightforward and distinct from siblings like provision or release tools.

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