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

With no annotations, the description carries the full burden and does disclose useful context: the upstream source (Nager.Date), coverage (~110 countries), and the payment model ($0.02/call, USDC, eip155:8453). However, it omits failure modes, rate limits, and confirmation that this is a read-only operation.

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?

Purpose is front-loaded, but the description is three sentences with redundancy between the opening line and the 'Use this when' line, plus a broken sentence and marketing filler ('Essential for scheduling agents'). Some trimming would help.

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 no-annotation, no-output-schema tool, the description is fairly complete: it names the source, coverage, cost, and the shape of returned data. It could say more about the op enum semantics and pagination/limit behavior, but the essentials are present.

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%, so the schema already documents all four parameters, and the description adds little syntax detail beyond mapping 'op' to the upcoming/full-year distinction. Baseline 3 is appropriate when the schema does the heavy lifting.

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 a specific verb (List) and resource (public holidays), plus scope (upcoming or full-year), data source (Nager.Date), and return fields (names, dates, nationwide flag). It does not explicitly distinguish itself from the related sibling live_business_days, so it falls short of a 5.

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?

'Use this when an agent needs to upcoming public holidays for ~110 countries' gives a use condition, but the sentence is grammatically broken and offers no when-not guidance or named alternatives (e.g., live_business_days). Usage is only implied, not delineated.

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