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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), yet the description adds substantial context beyond them: per-jurisdiction scope caveats (OPM federal only, Canada Labour Code, Japan statutory only, India Gazetted/Restricted classes, UAE 2026 dates only, Ireland excludes Good Friday) and the exact semantics of each route's holiday support. This is richer behavioral disclosure than the annotations provide.

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 opening usage sentence is front-loaded and the closing 'read-only catalogue discovery' sentence anchors the tool's role. The middle jurisdiction-caveat block is long and partly overlaps with sibling tool names, but each caveat carries real disambiguation value; the only cost is density.

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?

An output schema exists so return values need not be explained, and the description still covers route structure, territory-filter behavior, and every special-scope jurisdiction an agent must respect. For a 1-parameter discovery tool feeding many downstream calculators, nothing material is missing.

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 documents the territory parameter including that it returns one route instead of all 272 and normalizes to uppercase. The description repeats the 'one route when the optional territory filter is supplied' behavior without adding syntax or meaning beyond the schema, so the baseline 3 applies.

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 makes clear this is a catalogue/discovery tool that returns one machine-readable route per CLDR territory, and it names the distinct evidence packages (CLDR baseline, OpenWorkdays, OpenHolidays, official national calendars). It cleanly separates itself from the add_/check_/count_ working-day siblings, which are the consumers of these routes.

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?

Opens with an explicit when-to-use instruction ('Use this before a working-day or business-day task to select the correct evidence package') and closes with an explicit when-not ('it does not calculate a date or count and must not be reported as a calculation success'). The routing between alternatives is spelled out, not implied.

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