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

With no annotations, the description carries the full burden of behavioral disclosure. It does not mention side effects, permissions, error behavior for invalid or missing order IDs, or the nature of the returned URL. 'Build' hints at a pure function but this is not confirmed.

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 well-structured sentence that front-loads the action and resource. Every word earns its place with no redundancy.

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 single-parameter tool with no output schema and no annotations, the description provides a basic understanding of purpose and input but lacks details on return value format, error conditions, or security implications. It is sufficient for a simple build operation but not fully 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?

The schema has no description for orderId and the description adds the qualifier 'existing', which is useful. However, it does not explain the format of the order ID, how to obtain it, or any validation rules, leaving the parameter semantics minimally enriched.

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 'Build' with a clear resource 'public payable x402 URL' and scope 'for an existing order id'. It unambiguously distinguishes itself from sibling getter tools by being the only tool that constructs a URL.

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 clearly states the prerequisite that the order id must be existing, implying usage is for generating a payable URL after an order is created. However, it does not explicitly discuss when not to use it or mention any alternative tools, though the siblings are mostly unrelated getters.

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