APIbase

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

With no annotations provided, the description carries the full burden and successfully discloses key behavioral traits: it specifies the return payload structure ('Returns date, name (local + English), type'), authentication requirements ('No auth'), and data source/coverage ('Nager.Date', '100+ countries'). It omits rate limits and error handling details.

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 description consists of three highly efficient sentences. It front-loads the core functionality, follows with return value disclosure (critical given no output schema), and ends with operational constraints. Every sentence earns its place with zero redundancy.

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?

Given the tool's low complexity (2 simple parameters with complete schema coverage) and lack of output schema, the description adequately compensates by detailing the return values and data source. It provides sufficient context for an agent to invoke the tool correctly without needing additional clarification.

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?

The input schema has 100% description coverage (ISO country code with examples, year range with default), establishing a baseline of 3. The description mentions 'any country and year' which aligns with the parameters but does not add semantic meaning, syntax guidance, or format details beyond what the schema already provides.

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 clearly states the tool retrieves 'Public holidays for any country and year' with specific scope (100+ countries, national and regional). However, it does not explicitly differentiate from sibling tools calendar.holidays.next and calendar.holidays.premium, leaving the agent to infer based on naming alone.

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?

The description provides implicit usage guidance by stating 'No auth, free, open source,' which helps distinguish it from the 'premium' sibling. However, it lacks explicit when-to-use guidance versus calendar.holidays.next or clear prerequisites beyond the auth note.

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