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

With no annotations, the description carries the burden and does add real context: it discloses that names are localized per province, that weekend holidays surface the observed weekday, and that invocation costs $0.01 USDC on Base via x402 — an important payment/auth trait an agent cannot infer from the schema. It stops short of explaining the observation/substitution rule precisely or what happens for invalid province/year combinations.

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 sentences, front-loaded with the resource and scope, followed by the cost disclosure. No redundant restatement of the tool name and nothing padded.

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 two-parameter lookup with no output schema, the description covers what comes back (holiday names, actual date, observed weekday) and the payment model, which is enough for correct invocation. The only remaining gap is the precise weekend-substitution rule, which affects interpreting the returned weekday.

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% (year pattern 2000-2100, province enum with a clear description), so the schema already documents both parameters fully. The description merely restates 'province or territory' and 'given year' without adding format or edge-case semantics, which is the baseline-3 case.

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 exact resource (statutory/general holidays) plus scope (one Canadian province or territory, one year) and the returned content (local holiday names, dates, observed weekday). It is immediately distinguishable from canada_business_days and canada_sales_tax by subject matter, though it never names those siblings or states the contrast 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?

Usage is implied by the resource itself — call it when you need provincial holiday dates for a given year — and the x402 cost line gives a practical precondition (payment required). However there is no explicit when-to-use/when-not guidance and no pointer to the related canada_business_days or canada_sales_tax tools.

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