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

The annotations already declare readOnlyHint=true, so the bar for extra behavioral context is lower. The description adds meaningful execution details beyond the annotations: unpaid calls return an MCP PaymentRequired result, x402 clients can retry with _meta['x402/payment'], and execution fails closed if payment rails are unavailable. There is no contradiction with the annotations.

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 prose is bloated and repetitive, with repeated 'MISSING' placeholders and 'verified MISSING capability' phrasing, while the operational purpose is buried behind routing and payment boilerplate. It should be split into a short functional statement and a compact payment note.

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?

With no output schema, the description should clarify what the returned data represents, such as federal holidays, provincial holidays, or all Canadian holidays, and in what shape. It never states the result semantics, leaving the tool ambiguous against province-specific and metadata siblings despite thorough payment-behavior coverage.

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%, and the schema already describes the required year parameter with an example. The description adds no additional constraints or semantic detail such as valid year ranges or calendar type, so it earns the baseline but no bonus.

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 identifies this as the direct tool for 'the verified MISSING capability canadian_holidays_by_year' but never states what the tool actually does, such as retrieving Canadian holidays for a given year. The verb 'resolve' refers to capability resolution rather than the domain operation, and it does not distinguish the tool from holiday-related siblings like get_canadian_province_holidays_by_province_abbreviation_capability.

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?

It gives one concrete exclusion: do not first call list_verified_capabilities or search_verified_capabilities. However, 'prefer this tool when the caller's task matches this capability' is circular and provides no practical guidance for choosing this over canadian_holiday_metadata_by_id or the province-specific holiday tool.

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