Rebillia MCP Server

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

No annotations are provided, so the description carries full burden. It mentions 'GET /invoices' implying a read-only operation, but doesn't disclose behavioral traits like pagination behavior (implied by 'itemPerPage' and 'pageNo'), rate limits, authentication needs, or what happens when no filters are applied. For a list tool with 8 parameters and no annotations, this is a significant gap in 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 concise and front-loaded with the core purpose ('List invoices'), followed by a parameter list. However, the parameter listing is somewhat cluttered and could be structured better (e.g., grouping optional filters). It avoids unnecessary verbosity, earning a high score for efficiency.

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 list tool with 8 parameters, no annotations, and no output schema, the description is incomplete. It lacks details on return format (e.g., structure of invoice objects), pagination defaults, error handling, or how filters interact. Without annotations or output schema, the description should compensate more to guide the agent effectively.

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 8 parameters adequately. The description lists parameters but adds minimal value beyond the schema—it clarifies 'include' options with examples (detail, transactions, etc.), which is helpful but not extensive. Baseline 3 is appropriate when schema does the heavy lifting.

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 the basic action ('List invoices') and mentions the HTTP method ('GET /invoices'), which clarifies it's a read operation. However, it doesn't differentiate from sibling tools like 'get_invoice' (singular) or 'get_customer_invoices', leaving the scope ambiguous between listing all invoices vs. filtered subsets.

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 explicit guidance on when to use this tool versus alternatives like 'get_invoice' (for a specific invoice) or 'get_customer_invoices' (for customer-specific lists). The description only lists parameters without contextual advice, leaving the agent to infer usage from parameter names alone.

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