Expense Tracker MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions date format and default behavior, but doesn't address important aspects like whether this is a write operation (implied but not stated), what permissions are needed, how errors are handled, or what the response contains.

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 extremely concise with just two sentences that both add value. The first sentence states the core purpose, and the second provides important implementation detail about date formatting. There's zero wasted text.

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 write operation with 5 parameters and no annotations, the description is minimal but covers the essential action. The existence of an output schema means the description doesn't need to explain return values, but it should provide more guidance about usage context and behavioral expectations for a mutation tool.

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 adds minimal value beyond the schema. It only provides information about the 'date' parameter (format and default), leaving the other 4 parameters (amount, category, description, currency) without additional semantic context beyond what the schema provides.

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 ('Add a new expense') and resource ('expense'), making the purpose immediately understandable. However, it doesn't differentiate this tool from sibling tools like 'update_expense' or explain how it differs from them.

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 no guidance on when to use this tool versus alternatives like 'update_expense' or 'list_expenses'. It mentions date format but doesn't explain when this tool is appropriate versus other expense-related operations.

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