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

No annotations, so the description carries the full burden. It does disclose the substantive behavioral rule (weekends and US federal holidays are excluded) and that the calendar is US-specific, but nothing about authentication needs, error behavior, or what the response looks like.

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?

One tight sentence with the key exclusion rule front-loaded; the 'PRO' marker is compact. No wasted text, though the tier prefix is arguably noise for an agent.

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 three-parameter, no-output-schema tool the purpose is clear, but an agent still lacks the date input format and any confirmation of the return type (presumably an integer count). Those gaps are small but real.

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 coverage is only 33% — just access_token is documented. The from and to parameters are bare strings with no format hint, and the description's 'two dates' adds nothing about expected format (ISO-8601 vs. other) or whether ranges are inclusive. The description does not compensate for the coverage gap.

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?

States a specific verb (count) and resource (US business days between two dates) with the defining rule spelled out: weekends and federal holidays excluded. An agent can distinguish it from siblings like next_holidays or irs_deadlines, though the description never names them explicitly.

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?

No guidance on when to choose this over siblings such as due_date, irs_deadlines, or next_holidays, and no prerequisites or exclusions stated. The 'PRO' prefix hints at a paid tier but not at any usage condition.

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