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

With no annotations, the description does carry real behavioral weight: it discloses the $0.01 USDC-on-Base (eip155:8453) x402 charge, where the payment goes (params._meta["x402/payment"]), and the underlying HTTP GET endpoint. It omits what the response looks like, whether 'end' is inclusive, and how holidays outside the stated country scope are treated.

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 pricing sentence is duplicated near-verbatim ('$0.01 per call in USDC on Base via x402' then 'Price: $0.01 per call in USDC on Base (eip155:8453)'), and a service-level capability list is front-loaded where the tool's own function should be.

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 must carry everything. It says nothing about the return value (an integer count? a per-day breakdown?), range inclusivity, or error behavior for invalid/unsupported country ranges — the very things needed to call a counting tool 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 coverage is 100% — start/end carry YYYY-MM-DD format and country carries an enum with a holiday-regime note — so the schema does the heavy lifting. The description's only added semantic is 'net of holidays', which is marginal on top of that.

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 enumerates the whole service's four capabilities (business-day check, add N days, count between dates, list year holidays) instead of stating which one this tool performs. With siblings bizcal_api__add, __day, __workdays and __year present, an agent cannot determine from the text that this endpoint counts business days between start and end.

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 when-to-use guidance and no mention of the alternatives, even though the sibling set clearly splits the four advertised operations. The agent is left to infer from the name 'between' alone that this is the counting-range tool.

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