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

With no annotations, the description carries the full burden and does well: it discloses weekend exclusion, observed-weekday shifting of weekend holidays, half-open interval semantics, that skipped holidays are returned, and — importantly — that invocation costs $0.005 USDC on Base via x402. It stops short of describing the exact response shape (e.g. field names for the count).

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?

Two dense sentences with the core computation front-loaded and the payment note correctly placed last. Every clause carries information; the only mild redundancy is restating the interval boundary already present in the schema.

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 three-parameter, no-output-schema, no-annotation tool, this covers the essentials: what is counted, what is excluded, how boundaries behave, what extra data comes back, and the payment requirement. Only the precise return payload structure is left 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 description coverage is 100%, so the schema already documents all three parameters including the half-open 'to' semantics. The description's restatement of counting 'up to but not including the end date' reinforces that boundary but adds little beyond the schema's 'Day after the last day counted'.

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+resource: counting business days between two dates for a Canadian province/territory, with the exclusion rules spelled out. An agent can tell this apart from canada_sales_tax, though it never explicitly contrasts itself with canada_statutory_holidays, which is the closest sibling given this tool also mentions returning skipped holidays.

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 computation described (use it when you need a working-day count for a province), but there is no explicit when-to-use/when-not, and no guidance on choosing between this and canada_statutory_holidays when the user wants holiday data rather than a count.

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