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. It states the tool 'calculates' metrics but doesn't disclose whether this is a read-only operation, whether it requires specific permissions, what data sources it uses, or how it handles large date ranges. For a financial calculation tool with zero annotation coverage, this leaves significant behavioral questions unanswered.

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 two sentences: the first lists the comprehensive metrics calculated, the second mentions the date range filtering capability. Every element serves a purpose with zero wasted words, making it easy 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?

For a financial metrics calculation tool with no annotations and no output schema, the description is insufficient. It doesn't explain what specific metrics are returned, their format, whether calculations are real-time or cached, or any limitations. With 3 parameters and complex financial calculations implied, more context is needed for an agent to use this 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 three parameters (storeId, startDate, endDate) with their types and formats. The description mentions 'supports date range filtering' which aligns with startDate/endDate but doesn't add meaningful semantic context beyond what the schema provides. The baseline of 3 is appropriate when the 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 clearly states the tool calculates comprehensive financial metrics and lists specific metric categories (revenue, MRR/ARR, subscription metrics, order statistics, customer metrics). It distinguishes itself from siblings by focusing on financial metrics calculation rather than data retrieval or CRUD operations. However, it doesn't explicitly differentiate from potential similar financial analysis tools that might exist.

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 mentions date range filtering but provides no guidance on when to use this tool versus alternatives. With many sibling tools for retrieving specific data (get_customer, get_order, list_subscriptions, etc.), there's no indication whether this tool aggregates across those entities or when to prefer direct data retrieval versus this comprehensive calculation.

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