duo_list_user_phones

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

With no annotations, the description carries the full behavioral disclosure burden. It communicates that the operation is a read-only listing, names the returned fields, and flags the data as PII—useful context beyond the schema. It does not mention auth requirements or pagination behavior, but these are less critical for a simple list operation.

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 with a useful parenthetical. The verb and resource are front-loaded, and every word adds value.

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 complete parameter schema coverage and no output schema, the description provides enough context: it states the scope, what is returned, and the PII sensitivity. It could be slightly more explicit about pagination or how it differs from the global phone-listing sibling, but it is sufficient for correct invocation.

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%, so the baseline is 3. The description does not add any parameter-specific meaning, but it does not need to because the schema already documents userId, limit, and offset clearly.

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 uses a specific verb ('List') and resource ('phones enrolled to a user'), which clearly distinguishes this tool from the global duo_list_phones and other user-scoped list tools. It also names the key returned dimensions (number, platform/OS, capabilities), making the tool's purpose immediately identifiable.

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 phrase 'enrolled to a user' implies this is the tool for retrieving a specific user's phones, but it never explicitly states when to use this over duo_list_phones or other alternatives. No exclusions or alternative names are mentioned, so usage guidance is present only by implication.

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