lemon-squeezy-mcp

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

No annotations are provided, so the description carries the full burden. It describes the tool as a 'check' operation, implying read-only behavior, but doesn't disclose critical behavioral traits such as authentication requirements, rate limits, error conditions, or what happens if the subscriptionId is invalid. For a tool with no annotation coverage, this leaves significant gaps in understanding how it behaves.

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 sentences, front-loaded with the core purpose ('Check the status of a subscription') followed by specific use cases. Every word adds value without redundancy, making it efficient and easy to parse.

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 the tool's moderate complexity (single parameter, read operation) and no output schema, the description provides basic purpose and usage but lacks details on return values, error handling, or behavioral context. With no annotations and incomplete behavioral transparency, it's adequate for a simple lookup but could be more complete for reliable agent 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%, with the parameter 'subscriptionId' fully documented in the schema. The description doesn't add any additional meaning beyond the schema, such as format examples or constraints. With high schema coverage, the baseline score of 3 is appropriate, as the description doesn't compensate but also doesn't detract.

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 tool's purpose: 'Check the status of a subscription' with specific details on what information it provides (credits, status, renewal dates, billing). It distinguishes from siblings like 'list_subscriptions' (which lists multiple) or 'update_subscription' (which modifies). However, it doesn't explicitly contrast with 'get_subscription_invoice' or 'get_subscription_item', which are related but different resources.

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 usage context by stating 'Use this to verify...', suggesting it's for checking subscription details. However, it doesn't explicitly state when to use this vs. alternatives like 'list_subscriptions' (for multiple subscriptions) or 'get_subscription_invoice' (for invoice-specific data). No exclusions or prerequisites are mentioned.

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