Xero Expenses 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's a list operation. It doesn't disclose behavioral traits such as whether it's read-only, requires authentication, has rate limits, or returns paginated results. For a tool with zero annotation coverage, this is insufficient, scoring a 2.

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 directly states the tool's purpose without unnecessary words. It is front-loaded and appropriately sized, earning a perfect score for conciseness and structure.

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 tool's simplicity (0 parameters, no output schema) and lack of annotations, the description is minimally adequate. It states what the tool does but lacks details on behavior, output format, or error handling. For a list tool with no structured support, it meets the bare minimum, scoring a 3.

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 tool has 0 parameters with 100% schema description coverage, so no parameter documentation is needed. The description adds no parameter semantics, but the baseline for 0 parameters is 4, as the schema fully covers the absence of inputs without requiring compensation from 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 action ('List') and resource ('Xero bank accounts') with a specific purpose ('for expenses'). It distinguishes from siblings like 'xero_list_accounts' by specifying bank accounts rather than general accounts. However, it doesn't explicitly contrast with other list tools, keeping it at a 4 rather than a 5.

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 minimal guidance with 'for expenses', implying usage context but not specifying when to use this tool versus alternatives like 'xero_list_accounts' or other expense-related tools. No explicit when-not-to-use or prerequisite information is given, resulting in a basic score of 2.

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