Katzilla MCP

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

The description adds valuable behavioral context beyond annotations: it discloses the source (Nager.Date API with MIT License), update frequency ('updates annual'), and return format details ('Katzilla envelope { data, quality, citation }' with quality metrics and citation info). Annotations already indicate read-only, non-destructive, idempotent, and open-world traits, so the description complements these with practical implementation details without contradiction.

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 is front-loaded with the core purpose in the first sentence, followed by supporting details in a logical flow. Each sentence adds value: coverage info, source attribution, and return format explanation. There is no redundant or verbose content, making it efficient and well-structured.

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 moderate complexity, rich annotations (readOnlyHint, destructiveHint, idempotentHint, openWorldHint), 100% schema coverage, and presence of an output schema, the description is complete. It covers purpose, usage context, behavioral traits, source info, and return format, leaving no significant gaps for an agent to understand and invoke the tool effectively.

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 schema description coverage is 100%, with both parameters ('year' and 'countryCode') well-documented in the input schema. The description mentions the parameters implicitly ('for any country and year') but does not add significant semantic details beyond what the schema provides, such as format examples or constraints not already covered. This meets the baseline for high schema coverage.

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's purpose with specific verbs ('Get public holidays') and resources ('for any country and year using the Nager.Date API'). It distinguishes itself from sibling tools by specifying its unique domain (public holidays) and data source (Nager.Date API), unlike other demographics tools that focus on census data, economic indicators, or country information.

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 clear context about when to use this tool ('Get public holidays for any country and year') and mentions the coverage ('Covers 100+ countries with holiday types and regional info'). However, it does not explicitly state when not to use it or name specific alternative tools for similar data, though the sibling list shows no direct holiday alternatives.

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