Rebillia MCP Server

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

With no annotations provided, the description carries full burden and does well by disclosing key behavioral traits: it's part of a payment flow, returns a setupIntent.id for downstream use, and prohibits raw card data. However, it doesn't mention authentication requirements, rate limits, or error conditions.

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?

Three tightly focused sentences with zero waste. Front-loaded with the core purpose, followed by usage context and important constraint. Every sentence earns its place by providing essential 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?

For a 2-parameter tool with no annotations and no output schema, the description provides excellent context about the tool's role in a payment flow and downstream usage. However, without output schema, it could benefit from more detail about the returned setupIntent structure beyond just the .id property.

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 100%, so the schema already documents both required parameters (companyGatewayId, customerId). The description doesn't add any parameter-specific information beyond what the schema provides, maintaining the baseline score.

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 action ('Create or retrieve') and resource ('a setup intent via the gateway endpoint'), distinguishing it from sibling tools like create_customer_payment_method. It specifies the exact purpose within a payment flow context.

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?

Explicitly states when to use ('only as part of a gateway-agnostic payment method flow') and provides a concrete alternative usage pattern ('the returned setupIntent.id can be used as paymentMethodNonce for create_customer_payment_method'). Also includes a clear exclusion ('No raw card data').

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