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

With no annotations, the description carries the full behavioral burden. It usefully discloses the counting rule, Mon-Fri scope, and inclusive endpoints, but omits timezone assumptions, date-format expectations, and invalid-range handling.

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?

A single well-formed sentence that is front-loaded with the core action and contains no filler. Every phrase adds relevant information.

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 simple count tool, the description states the operation and inclusivity clearly. But with no output schema, no annotations, and 0% parameter coverage, it should specify input date format and explicitly confirm that the result is a count.

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%, and the nested payload contains required start and end fields with no descriptions. The description mentions 'two dates' but does not name the parameters, specify date formats, or clarify the nested payload structure.

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 and resource: count weekdays (Mon-Fri). It also defines the scope with inclusive endpoints, which distinguishes it from generic interval tools like time_between.

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?

Usage is implied by the name and description: use it when counting business days between two dates. However, there is no explicit when-to-use, when-not-to-use, or alternative sibling guidance.

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