Google AP2 Checkout/Payment Mandate (VDC) Builder & Validator

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

The descriptions adds context beyond annotations: it states the tool runs client-side, zero PII, zero network, and inputs are applied via AIN Bridge. The annotations already declare readOnlyHint, destructiveHint, and idempotentHint, so the description provides valuable operational details without contradiction.

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 three sentences, front-loaded with the main action, and every sentence adds value. No redundant or irrelevant information.

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 single parameter and presence of annotations, the description covers the tool's operation well. It explains the scope, the rendering behavior, and the parameter semantics. Minor missing context on 'Open/Closed' VDC types, but overall complete.

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?

With 100% schema coverage, the baseline is 3. The description adds meaning by explaining that the 'inputs' parameter is a map of tool input element IDs to values, applied via AIN Bridge prefill. This clarifies the usage beyond the schema's brief description.

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 builds or validates a Google AP2 Checkout/Payment Mandate VDC and distinguishes it from the AINumbers Policy Mandate. It specifies the target (external AP2 spec) and mentions rendering the interactive AINumbers tool, providing a specific verb+resource combination.

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 mentions targeting the external AP2 spec and not the AINumbers Policy Mandate, giving some guidance on when to use. However, it does not explicitly exclude alternatives or compare with sibling tools like 'validate_ap2_mcp_policy' or 'ap2_aml_mandate_builder', leaving usage context implied rather than explicit.

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