verify_card_validation_data

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

No annotations are present, so the description carries the burden. It discloses supported key types (C0 CVK, E4/E6 EMV) and that verification is against the issuer CVK, which is useful. However, it does not explicitly state side effects (or their absence), permissions, error behavior, or return format for an unannotated tool.

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 compact and front-loaded with the use case before the Args list. The opening sentence and the 'Verify card validation data' sentence are slightly redundant, but supported key types and structured parameter notes earn their place.

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 4-required-parameter tool with no output schema and no annotations, the description covers purpose, usage, key types, and parameter basics. It omits the return/response shape and does not fully expand the nested verification_attributes object, leaving an agent to infer success/failure semantics.

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 provides only types and requiredness (0% coverage), but the Args block supplies real semantics for every parameter: ARN/alias for key_identifier, 12-19 digit constraint for PAN, algorithm/card-data meaning for verification_attributes, and the value-to-verify for validation_data. Verification_attributes remains somewhat open-ended by pointing to generate_card_validation_data, so it is strong but not exhaustive.

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 opens with a specific action—validating a card at POS or CNP by verifying CVV/CVV2/iCVV against the issuer's CVK—and then states the core operation as 'Verify card validation data'. It clearly names the resource and supported algorithm families, and the operation is distinguishable from siblings like generate_card_validation_data or verify_mac.

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?

It gives explicit trigger contexts: validating a card at POS/CNP, or testing CVK-based validation before writing production logic. It does not explicitly name alternatives to avoid, but the 'validating ... verifying' framing and the reference to generate_card_validation_data make the intended use reasonably unambiguous.

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