Expense Tracker MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. While 'set or update' implies a mutation operation, it doesn't specify whether this requires admin permissions, if changes are reversible, what happens to existing budgets, or any rate limits. This leaves significant gaps in understanding the tool's behavior and risks.

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 any fluff or redundancy. It is appropriately sized and front-loaded, making it easy for an agent to parse quickly.

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 that there is an output schema (which handles return values), the description doesn't need to explain outputs. However, for a mutation tool with 3 parameters, 0% schema coverage, and no annotations, the description is incomplete—it lacks details on permissions, error cases, and parameter semantics, making it only minimally adequate.

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 0%, meaning none of the parameters are documented in the schema. The description mentions 'category' and 'monthly budget limit', which loosely map to the 'category' and 'monthly_limit' parameters, but it doesn't explain what a 'category' entails (e.g., predefined list or free text) or the format for 'monthly_limit' (e.g., positive number). The 'currency' parameter is not addressed at all, failing to compensate for the low coverage.

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 ('set or update') and resource ('monthly budget limit for a category'), making the purpose specific and understandable. However, it doesn't explicitly distinguish this tool from sibling tools like 'get_budget_status' or 'update_expense' which might also relate to budget management, preventing a perfect score.

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. For example, it doesn't clarify if this should be used instead of 'update_expense' for budget changes, or if it's for initial setup versus ongoing adjustments, leaving the agent with minimal context for selection.

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