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

With no annotations, the description carries the full behavioral burden. It discloses that Lava.top processes payment and that the minimum top-up is 8 EUR, but omits whether it returns a URL, authentication requirements, payment flow, or any side effects.

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 two short sentences, front-loaded with purpose and free of redundant text. The slightly vague opening keeps it from a top score, but it is appropriately sized for a simple one-parameter tool.

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 simple one-parameter tool with no output schema and no annotations, the description covers purpose, payment processor, and minimum amount. However, it leaves out return behavior and payment flow, which are material for a payment-link tool.

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. It adds the minimum top-up constraint of 8 EUR, which clarifies amount_eur, but does not explain the default, accepted increments, or whether values below 8 are rejected.

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 identifies the resource (API balance) and the general action (topping up), but the wording 'Where to top up' does not explicitly state that the tool generates or returns a payment link. It also does not differentiate itself from siblings like get_balance or parse_invoice.

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 implies the tool is used when topping up the API balance, but gives no explicit when-to-use guidance, exclusions, or comparison to alternatives. The minimum amount is a constraint, not usage guidance.

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