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: the default limit (20), pagination behavior ('Response includes cursor/has_more'), and the detailed return structure. It also mentions filtering capabilities and the types of line items included. The only minor gap is lack of explicit rate limit or authentication requirements.

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 and critical warning. The detailed return structure is necessary given no output schema, but the paragraph could be slightly more structured (e.g., bullet points for return fields). Every sentence adds value, with no redundant information.

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 complexity (5 parameters, 0% schema coverage, no output schema, no annotations), the description is remarkably complete. It covers purpose, usage guidance, parameters, return structure, pagination behavior, and filtering options. The only minor omission is explicit error handling or authentication requirements, but overall it provides everything needed for effective tool use.

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?

With 0% schema description coverage, the description fully compensates by explaining all 5 parameters: it explicitly lists the four filter parameters (data_source_uuid, external_id, customer_uuid, validation_type) and provides context about the limit parameter with its default and warning. It also explains what values validation_type accepts ('valid', 'invalid', 'all').

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 action ('List invoices') and specifies the resource scope ('contain line items generating subscription revenue'), distinguishing it from sibling tools like 'retrieve_invoice' (singular) and 'import_invoices' (write operation). It provides specific context about the API source (ChartMogul API).

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 usage context with the 'LIMIT WARNING' advising against requesting more than 20 items to avoid excessive token usage, which implicitly suggests when to use this tool (for browsing/listing) versus alternatives like 'retrieve_invoice' for single-item lookups. However, it doesn't explicitly name alternatives or state when-not-to-use scenarios beyond the limit warning.

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