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

No annotations are provided, so the description carries the full behavioral burden. It does useful work by explaining the shape of the response (weekend_days vs weekend_definitions with full history), but it never states whether this is a read-only lookup, what happens with an invalid calendar code, or how large the history payload may be.

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 tight sentences with no filler; the core capability is front-loaded and the return-field explanation follows immediately. Nothing is repeated from 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?

With no output schema and no parameter descriptions, the description steps in to explain the two returned fields and their temporal scope, which is the key ambiguity for this tool. It falls short only on operational details (read-only nature, error behavior, code discovery).

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 0% and the single parameter has no description, so the description must compensate — and it does, supplying an example value format ('USD.FX') and indicating that exactly one calendar code is expected. It does not point to a way to enumerate valid codes, which would have made it a 5.

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 the resource precisely: weekend definitions and working weekends scoped to a single calendar code, with a concrete example format (USD.FX). The distinction from holiday-oriented siblings is implicit in the resource name, but no sibling is named 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 being retrieved — an agent would reach for this when it needs weekend structure for a calendar code. There is no explicit when-not guidance and no pointer to alternatives such as get_holidays or list_calendars for discovering valid codes.

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