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

With no annotations, the description carries the full burden; it does disclose that business-day counting is province-dependent (an important behavioral trait implying a holiday calendar) and flags 'PRO' tier gating. It omits what an invalid province does, whether the result includes holidays/weekends in output, and whether access_token is required for all calls.

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 dense line with no filler, and the core operation is front-loaded. The 'PRO.' prefix is terse to the point of being cryptic, but it costs almost no space.

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?

No annotations and no output schema, so the description should have specified the return shape (a date string?) and premium/token behavior. As written it is enough to construct a call but leaves the response format and province value space unspecified.

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 40% (start, days, and province are undocumented in the schema), but the description partially compensates by explaining that start and days feed an additive calculation and that province scopes the holiday logic and mode selects calendar vs business. It still doesn't give formats (date string shape, valid province codes, integer vs fractional days).

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 the specific computation (start + N calendar or business days) and the resource it produces (an invoice/contract due date) scoped to a province. It is distinguishable from siblings like business_days because it returns a date rather than a count, though it never names those siblings 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?

The domain cue ('Invoice/contract due date') implies when to reach for it, but there is no explicit when-to-use, when-not-to-use, or pointer to business_days/next_holidays for related calculations. Usage must be inferred from the scenario name.

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