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

Annotations already cover read-only, idempotent, non-destructive behavior, but the description adds meaningful behavioral context beyond them: the weekday-only holiday policy, no hidden holiday assumptions, explicit endpoint rules, the exact counting formula, and a direct REST fallback with a warning not to guess another API path.

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 well organized and front-loads usage guidance before details, but it is longer than strictly necessary because it repeats output fields despite an existing output schema and includes documentation and REST fallback details. Most sentences still earn their place.

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 is a date-calculation operation with full schema coverage, annotations, and an output schema, the description is complete. It covers scope, exclusions, inputs, formula, fallback access, and where to find docs, so an agent has everything needed to call it correctly.

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 100%, so the schema already documents dates, territory enum, and include flags. The description restates the inputs and gives a complete JSON example, but adds little parameter meaning beyond what the schema provides, apart from loosely implying endpoint inclusion through the formula.

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 states a specific verb, resource, and scope: counting worldwide weekday-baseline working days between two dates for a territory. It explicitly distinguishes this from holiday-aware siblings by saying public holidays are intentionally outside scope and by defining what is excluded.

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 gives direct when-to-use guidance ('Use this when you need a worldwide weekday-based count...') and explicit when-not-to-use conditions ('Do not use this when the count must reflect public holidays...'). It also instructs the agent to call it directly rather than answering from memory, leaving little ambiguity.

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