xendit-mcp

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the lookup action but doesn't cover critical aspects like authentication requirements, rate limits, error handling, or response format. This leaves significant gaps for an agent to understand how to invoke and interpret results safely and effectively.

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 front-loads the core action ('Look up a VA payment') and includes essential context about the parameter. There is no wasted verbiage, making it highly concise and well-structured for quick comprehension.

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 lack of annotations and output schema, the description is incomplete. It covers the basic purpose and parameter context but omits behavioral details (e.g., authentication, errors) and return value information. For a tool that likely involves sensitive payment data, this leaves the agent under-informed about critical operational aspects.

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 single parameter 'paymentId' documented as 'VA payment_id'. The description adds context by specifying it's 'the ID returned in the VA paid callback', which clarifies the source and purpose of the ID. This aligns with the baseline score of 3, as the schema already does the heavy lifting, and the description provides modest additional meaning.

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 ('Look up') and resource ('a VA payment'), specifying it's for Virtual Account payments. However, it doesn't explicitly differentiate from sibling tools like 'xendit_get_transaction' or 'xendit_get_payment_request', which might also retrieve payment information but for different payment methods or contexts.

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 by mentioning 'payment_id (the ID returned in the VA paid callback)', suggesting it's for retrieving specific VA payments after a callback event. However, it doesn't provide explicit guidance on when to use this tool versus alternatives like 'xendit_get_transaction' or 'xendit_list_transactions', leaving some ambiguity about context and exclusions.

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