create_virtual_card

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions that the tool 'Returns secure card details,' which adds some context about output behavior, but fails to address critical aspects like authentication requirements, rate limits, error conditions, or whether the creation is reversible. For a mutation tool with zero annotation coverage, this is insufficient.

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—just two sentences that directly state the tool's purpose and what it returns. There is no wasted language, and the information is front-loaded appropriately, making it efficient for an agent to parse.

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 complexity of creating a financial instrument (a virtual card), the lack of annotations, no output schema, and 0% schema description coverage, the description is incomplete. It doesn't cover parameter meanings, error handling, security implications, or detailed return values, which are crucial for such an operation.

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 description coverage is 0%, meaning the input schema provides no descriptions for the two parameters (merchant, amount_cents). The tool description does not add any semantic meaning for these parameters—it doesn't explain what 'merchant' represents, what format 'amount_cents' should be in, or any constraints. This leaves the parameters largely undocumented.

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 action ('Create a single-use virtual card') and the resource ('via Privacy.com'), providing a specific verb+resource combination. However, it doesn't explicitly differentiate this tool from its siblings (get_funding_sources, secure_auto_fill), which would be needed for a perfect score.

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 no guidance on when to use this tool versus its siblings or any alternatives. It mentions the tool's purpose but offers no context about prerequisites, appropriate scenarios, or exclusions, leaving the agent with minimal usage direction.

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