phone_system_active_numbers

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

The annotations already declare readOnlyHint=true and idempotentHint=true, covering the safety profile. The description adds no behavioral context beyond the name—no mention of pagination defaults, filtering behavior, return format, or any side effects. It neither contradicts nor enriches the annotations, so it contributes little to behavioral transparency.

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, short sentence that directly states the purpose. It is extremely concise and front-loaded with the core operation, with zero wasted words. This is an excellent example of conciseness.

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 tool with 5 parameters and no output schema, the description is minimal. It doesn't explain what 'active numbers' means in the phone system context, nor does it describe how this relates to other phone system tools or what an agent should expect from the response. The description is inadequate for an agent to correctly invoke this tool across varied use cases.

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% with all 5 parameters (page, pageSize, locationId, searchFilter, skipNumberPool) documented in the input schema. The description itself does not add any parameter-level meaning, but since the schema carries the full burden, a baseline of 3 is appropriate.

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 'List active numbers' clearly identifies the verb (List) and the resource (active numbers). It is specific enough to convey the operation, but it does not differentiate from sibling tools like phone_system_available_numbers, which could be confused with active numbers since both may return phone numbers. The lack of scope or distinction prevents 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?

There is no guidance on when to use this tool versus alternatives such as phone_system_available_numbers or phone_system_purchase_phone_number. No mention of typical scenarios, exclusions, or prerequisites. The agent is left to infer usage from the name and schema, which is insufficient.

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