direct.list_vcards

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

With no annotations, the description carries the full behavioral burden, yet it only implies a read operation via 'List'. It does not disclose authentication requirements, whether account_id is necessary, pagination behavior, filtering defaults, or any other operational trait. This is well below what a 7-parameter tool needs.

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?

At two words, the description is under-specified rather than concise. It is front-loaded but does not contain enough information to be useful for an agent facing a complex, nested schema.

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 seven parameters including nested objects, an 'advanced' raw params override, and no output schema, the description is completely inadequate. It omits required-parameter context, return format, filtering, and account resolution details that an agent needs to invoke the tool correctly.

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 input schema already documents all seven parameters in detail. The description adds no parameter information at all, making the baseline of 3 appropriate when the schema does all the work.

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 states a specific verb and resource: 'List' + 'vCards'. It is clear what the tool does, but it offers no differentiation from sibling list tools such as direct.list_sitelinks or direct.list_adextensions. It is not vague, but it leaves sibling routing entirely to the agent's inference.

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, no prerequisites, and no exclusions. The agent must infer usage entirely from the name and schema.

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