get_phone_number

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

With no annotations provided, the description must disclose behavioral traits. It only says 'Get details' which implies a read operation but does not mention authentication requirements, error behaviors (e.g., not found), rate limits, or any side effects. This is a significant gap for a tool with zero annotation coverage.

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, with a single purpose statement and an args section. Every word earns its place and the structure is front-loaded. It could be slightly more detailed, but it avoids unnecessary fluff.

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 get operation with one parameter and an output schema (not shown but indicated), the description is fairly complete. It clarifies the input source and the scope. However, it omits any mention of error handling or prerequisites, which would make it more robust.

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 schema has 0% coverage, but the description compensates by explaining the parameter: 'phone_number_id: The phone number ID (from list_phone_numbers).' This adds meaningful context beyond the schema's type/name, clarifying the source and role of the parameter.

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: 'Get details for a single provisioned phone number.' It uses a specific verb ('Get') and resource ('phone number'), and explicitly scopes to a single provisioned number, distinguishing it from sibling list_phone_numbers or provision_phone_number.

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 usage context by noting the phone_number_id comes from list_phone_numbers, suggesting a follow-up step. However, it does not explicitly state when to use this tool versus alternatives or mention exclusions, so usage guidance remains implicit.

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