Rebillia MCP Server

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

With no annotations provided, the description carries the full burden. It discloses key behavioral traits: it's a read operation (implied by 'List'), returns paginated results, and supports optional detail inclusion. However, it doesn't mention authentication requirements, rate limits, error conditions, or what happens with invalid subscription IDs.

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 efficiently structured in three sentences: purpose statement, endpoint reference, and usage guidance. Every sentence adds value with zero wasted words, making it easy to parse and understand quickly.

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 read operation with 4 parameters and no output schema, the description is reasonably complete about what the tool does and basic usage. However, without annotations or output schema, it lacks details about response format, error handling, and authentication requirements that would be helpful for an AI agent.

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 all 4 parameters thoroughly. The description adds minimal value beyond the schema by mentioning the 'include' parameter's purpose and examples, but doesn't provide additional semantic context for other parameters like pagination behavior.

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 verb ('List') and resource ('invoices for a subscription'), making the purpose specific. It distinguishes from sibling tools like 'get_invoice' (single invoice) and 'list_invoices' (all invoices) by focusing on subscription-specific invoices.

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 clear context for usage ('List invoices for a subscription') and mentions an alternative approach for including details ('Use include for line-item detail and transactions'). However, it doesn't explicitly state when NOT to use this tool versus alternatives like 'get_customer_invoices' or 'list_invoices'.

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