Katzilla MCP

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

The description adds valuable behavioral context beyond annotations: it specifies the data source (Free Dictionary API with CC BY-SA 3.0 license), update frequency ('updates daily'), and details about the return format ('Katzilla envelope { data, quality, citation }' with quality scores and citation info). Annotations cover read-only, non-destructive, idempotent, and open-world hints, so the description complements these with practical implementation 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 is well-structured and concise, with two sentences that efficiently cover purpose, features, source, and output format without unnecessary details. Every sentence adds value, and it is front-loaded with the core functionality.

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 complexity (a read-only lookup with two parameters), rich annotations (covering safety and idempotency), and the presence of an output schema (implied by 'Returns the Katzilla envelope'), the description is complete. It adequately explains what the tool does, its source, and output structure, leaving no significant gaps for agent understanding.

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 description does not add meaning beyond the input schema, which has 100% coverage with clear descriptions for both parameters ('word' and 'language'). The baseline score of 3 is appropriate since the schema fully documents the parameters, and the description's mention of 'Supports multiple languages' only loosely relates to the 'language' parameter without adding specifics.

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 ('look up') and resources ('word definitions, phonetics, synonyms, and usage examples'), and distinguishes it from siblings by specifying it uses the Free Dictionary API for cultural/reference purposes, unlike other tools in the list that focus on different domains like agriculture, crime, or economics.

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 for when to use this tool ('Look up word definitions... from the Free Dictionary API') and mentions support for multiple languages, but does not explicitly state when not to use it or name specific alternatives among the sibling tools (e.g., culture__wiktionary for similar reference purposes).

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