ChartMogul 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 and does well by disclosing key behavioral traits: it warns about a default limit of 20 and discourages excessive requests to avoid token usage, describes the return format (subscription event objects with details), and mentions pagination (cursor/has_more). However, it lacks details on error handling or authentication needs.

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 appropriately sized and front-loaded with the core purpose, followed by important warnings and details. Every sentence adds value, but the long enum list for 'event_type' could be slightly condensed, though it's necessary for clarity.

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 tool with 9 parameters, 0% schema coverage, and no output schema, the description is quite complete: it covers purpose, usage constraints, parameter semantics, and response format. However, it lacks information on error cases or example responses, which would enhance completeness given the complexity.

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?

Given 0% schema description coverage, the description compensates fully by listing all 9 parameters with semantic details: it explains filter purposes (e.g., 'data_source_uuid' for filtering by data source), provides enum values for 'event_type', specifies date formats (ISO 8601), and clarifies the 'limit' parameter's default and warning. This adds significant meaning beyond the bare schema.

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 specific action ('List subscription lifecycle events') and resource ('subscription events'), distinguishing it from sibling tools like 'list_customers' or 'list_invoices' by focusing on subscription-specific events. It also mentions tracking subscription changes, which further clarifies the purpose.

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 by specifying filters and a limit warning, but it does not explicitly state when to use this tool versus alternatives like 'list_customer_subscriptions' or 'update_subscription_event'. It implies usage for filtered event listing without naming specific alternatives.

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