xendit-mcp

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

With no annotations provided, the description carries full burden but only states it 'Returns available balance by account type.' It doesn't disclose behavioral traits like authentication requirements, rate limits, error conditions, whether this is a read-only operation, or what format the return value takes. This is inadequate for a financial API tool with zero annotation coverage.

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 perfectly concise with two sentences that each earn their place: the first states the core purpose, the second provides essential return value context. No wasted words, and the most important information is front-loaded.

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 balance-checking tool with 2 parameters and no output schema, the description is minimally complete about what it does but lacks crucial context about authentication, error handling, and return format. The absence of annotations and output schema means the description should compensate more than it does.

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?

The description mentions 'account type (CASH, HOLDING, TAX)' which aligns with the accountType parameter's enum values, but doesn't explain what these account types mean or add meaning beyond the 100% schema coverage. With complete schema documentation, the baseline is 3 even without additional parameter semantics in the description.

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 ('Get Xendit account balance') and resource ('account balance'), distinguishing it from sibling tools that focus on disbursements, invoices, payments, refunds, and transactions rather than account balances. It provides the exact verb+resource combination needed.

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 mentioning account types (CASH, HOLDING, TAX), suggesting this tool is for checking different balance categories. However, it doesn't explicitly state when to use this vs. alternatives like transaction listings or provide any exclusions. The guidance is implied rather than explicit.

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