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

The description adds behavioral context by stating which entities are included ('ones in a collection') and explicitly listing the valid period formats (e.g., 'this week,' 'this month,' 'all time'), providing constraints beyond the schema or annotations.

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, achieving its goal in a single, well-structured paragraph. Every sentence is functional, starting with the core action and ending with the guaranteed output.

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 low complexity of the function (a singular count), the description is highly complete. It covers scope, filtration mechanisms, and the precise nature of the return value, leaving no functional questions unanswered for the agent.

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?

Since schema coverage is 100%, the description adds crucial semantic value by clarifying that filtering is optional and detailing the purpose of the date/period parameters—to count within a specific temporal scope.

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 defines the purpose as counting notes while distinguishing it from drafts, which immediately helps differentiate it from similar sibling tools.

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?

It establishes clear boundaries regarding what is counted (user notes, included in collections) and what is excluded (draft notes). While it doesn't explicitly name alternatives, it defines its scope well enough for usage context.

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