Katzilla MCP

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

The description adds valuable behavioral context beyond the annotations. Annotations indicate read-only, non-destructive, idempotent, and open-world operations. The description supplements this by specifying the data source ('Open Library / Internet Archive'), update frequency ('updates daily'), licensing ('Public Domain (metadata)'), and the structure of the return envelope ('Katzilla envelope { data, quality, citation }') with details on quality scoring and citation components. This enriches the agent's understanding without contradicting the annotations.

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 efficiently structured in two sentences: the first covers the tool's purpose, scope, and output, and the second details the source, updates, and return format. Every sentence adds essential information without redundancy, making it front-loaded and easy to parse for an AI agent.

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 (search with metadata return), rich annotations (readOnlyHint, destructiveHint, idempotentHint, openWorldHint), and the presence of an output schema (implied by 'Returns the Katzilla envelope'), the description is complete. It covers the tool's purpose, behavioral traits, data source, update frequency, licensing, and output structure, providing sufficient context for an agent to use it effectively without needing to explain return values in detail.

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, with clear documentation for 'query' (search query types) and 'limit' (result count with constraints). The description does not add any additional parameter semantics beyond what the schema provides, such as search syntax examples or result ordering. Given the high schema coverage, a baseline score of 3 is appropriate, as the description relies on the schema for parameter details.

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 explicitly states the action ('Search Open Library's catalog'), the resource ('over 20 million books'), and the output ('Returns book metadata including title, author, publication year, and cover images'). It clearly distinguishes this as a search tool for book metadata from Open Library, differentiating it from other culture tools like 'culture__gutendex' (which focuses on Project Gutenberg books) or 'entertainment__book-search' (which appears to be a general book search).

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: for searching Open Library's catalog of books. It implies usage by stating the source ('Open Library / Internet Archive') and the type of data returned (metadata). However, it does not explicitly mention when not to use it or name specific alternatives among the sibling tools (e.g., 'culture__gutendex' for public domain ebooks or 'entertainment__book-search' for broader book searches), which prevents a perfect score.

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