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 optional filters and date format, but fails to address critical behavioral aspects: whether this is a read-only operation (implied but not stated), pagination behavior (limit parameter exists but not explained), authentication requirements, rate limits, or what happens when no filters are applied. For a tool with 4 parameters and no annotation coverage, this is insufficient.

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 only two sentences that each serve clear purposes: stating the tool's function and specifying date format. There's zero wasted language, and the most critical information (date format) is appropriately included. This is a model of efficient description writing.

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 has an output schema (which handles return values), 4 parameters with 0% schema coverage, and no annotations, the description is minimally adequate. It covers the basic purpose and date format but misses important context: no guidance on usage versus siblings, incomplete parameter semantics, and insufficient behavioral transparency for a filtering/list tool. The output schema reduces the burden, but significant gaps remain.

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%, so the description must compensate. It adds value by specifying the date format (YYYY-MM-DD) for date parameters, which isn't in the schema. However, it doesn't explain the 'category' parameter's possible values, the 'limit' parameter's purpose (pagination vs result limiting), or the relationship between start_date and end_date. The description provides some semantic context but leaves significant gaps.

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 ('List') and resource ('expenses'), making the purpose immediately understandable. It distinguishes from siblings like 'add_expense' or 'delete_expense' by focusing on retrieval rather than modification. However, it doesn't specify whether this lists all expenses or has a default scope, which prevents 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 like 'get_expense_summary' or 'export_expenses'. It mentions optional filters but doesn't explain when filtering is appropriate or what scenarios warrant this tool over others. This leaves the agent without clear decision-making criteria.

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