create_payment_preference

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 states the tool creates a payment preference and returns a URL, but lacks details on permissions, rate limits, error handling, or whether the operation is idempotent. This is a significant gap for a mutation 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 a single, efficient sentence that front-loads the core action and result. It avoids redundancy but could be slightly more detailed given the lack of annotations and schema descriptions.

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 mutation tool with 6 parameters, 0% schema coverage, no annotations, and no output schema, the description is incomplete. It covers the basic purpose and return value but lacks parameter explanations, behavioral details, and usage context, which are critical for effective tool invocation.

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 0%, so the description must compensate for undocumented parameters. It does not explain any parameters, such as the meaning of 'back_urls' or 'notification_url', leaving all 6 parameters without semantic context beyond the schema's structure.

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 specific action ('Creates a Mercado Pago checkout payment preference') and resource ('payment link'), distinguishing it from siblings like create_refund or get_payment. It also specifies the return value ('init_point URL for redirecting buyers'), making the purpose unambiguous.

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 alternatives like create_refund or search_payments. It mentions the return value but does not specify prerequisites, such as authentication or account setup, leaving usage context unclear.

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