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

With no annotations, the description carries the burden of behavioral disclosure. It mentions localStorage (client-side persistence) and CSV output, which are useful. However, it does not explain how data is entered, whether operations are reversible, or any limitations (e.g., no cloud sync). This is adequate but incomplete.

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, dense sentence that front-loads the core functionality (monthly sales/profit/fees) and adds key context (localStorage, CSV output for tax). Every word contributes value; no fluff.

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 no-parameter, no-output-schema tool, the description adequately covers the main functionality, storage mechanism, and output format. It tells the user what the tool does and what it produces. Minor gaps like data entry method or multi-year support are acceptable given the simplicity.

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 zero parameters, so the empty schema is fully covered. Per guidelines, the baseline is 4 for 0 params, and the description adds no parameter-specific info (there are none) but clarifies the tool's scope, which is sufficient.

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 tool tracks monthly sales, profits, and fees in localStorage and exports CSV for tax filing. It uses a specific verb ('manage') and resource ('Mercari sales tracker'), distinguishing it from siblings like 'mercari-calculator' or other sales dashboards.

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 clear context (monthly revenue/profit/fee tracking, CSV for tax filing) that implies when to use it, but it does not explicitly mention alternatives or when not to use it. The 'Browser-based tool' note and focus on management vs. calculation suggest differentiation from calculator siblings.

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