get_payment_link

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

With no annotations, the description must disclose behavior. It mentions that a 409 is returned if no open invoice exists, which is valuable. However, it does not describe the success response format, authentication requirements, or any side effects, leaving a gap in behavioral transparency.

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 an efficient single sentence plus an error code note, with no redundant wording. All information is relevant and front-loaded, making it easy 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?

For a tool with a single parameter and no output schema, the description covers the core resource and even the error case. While it does not explicitly state the success return (the link itself is implied by the description), it is sufficiently complete for the tool's simplicity.

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 coverage is 0%, so the description should explain the parameter. It only implicitly refers to subscription_id as 'de uma assinatura' (of a subscription), giving minimal context. It does not clarify the format, required value, or any constraints beyond it being a subscription ID, so the parameter semantics are under-addressed.

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 states it provides a public payment link for the open invoice of a subscription, clearly identifying the resource and purpose. However, it does not explicitly differentiate from sibling tools like get_order_payment_link, which may also deal with payment links. The 409 error mention adds a specific behavioral hint that aids understanding.

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?

No guidance is given on when to use this tool versus alternatives. The description only specifies the condition (open invoice) but does not mention when not to use it or direct to sibling tools for other cases, leaving the agent to infer selection from the name and sibling list.

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