lemon-squeezy-mcp

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

No annotations are provided, so the description carries full burden for behavioral disclosure. It states 'generate' which implies a write/mutation operation, but doesn't clarify whether this creates a new invoice, triggers billing, requires specific permissions, has side effects (e.g., sending notifications), or what the output contains. For a mutation tool with zero annotation coverage, this leaves significant behavioral gaps.

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 a single, efficient sentence that directly states the tool's purpose without unnecessary words. It's appropriately sized for a simple tool with one parameter and is front-loaded with the core action. Every word earns its place, making it easy for an agent to parse 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?

Given this is a mutation tool (implied by 'generate') with no annotations and no output schema, the description is insufficiently complete. It doesn't explain what the tool returns, error conditions, permissions needed, or how it differs from similar invoice operations. For a tool that likely creates financial records, more context about behavior and outcomes is needed for safe invocation.

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 input schema already documents the single parameter 'subscriptionInvoiceId' with its type and description. The tool description adds no additional parameter context beyond what's in the schema (e.g., format examples, relationship to other entities, or why this ID is needed). With high schema coverage, the baseline score of 3 is appropriate as the description doesn't enhance parameter understanding.

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 'generate' and the resource 'invoice for a subscription', making the purpose immediately understandable. It distinguishes from sibling tools like 'generate_order_invoice' by specifying subscription context, though it doesn't explicitly contrast with other invoice-related tools. The description avoids tautology by not just restating the name.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an existing subscription), contrast with similar tools like 'generate_order_invoice' or 'issue_subscription_invoice_refund', or indicate when this operation is appropriate versus other invoice-related actions. The agent must infer usage from context alone.

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