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 data source, update frequency ('updates daily'), and return format ('Katzilla envelope { data, quality, citation }') with details on quality scoring and citation contents. Annotations already indicate read-only, non-destructive, idempotent, and open-world traits, so the description complements these with operational specifics 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 efficiently structured in two sentences: the first states the purpose and usage, the second details the source and return format. Every sentence adds critical information (e.g., source, update frequency, output structure) with no redundant or vague phrasing, making it front-loaded and highly concise.

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 simplicity (one parameter, high schema coverage, annotations present, output schema exists), the description is complete. It covers purpose, usage, behavioral traits, source details, and output format, providing all necessary context for an agent to invoke the tool correctly without needing to rely solely on structured fields.

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 the parameter 'reference' fully documented in the schema. The description mentions the parameter indirectly by describing supported reference formats ('single verses, ranges, and multiple references'), but adds minimal semantic value beyond what the schema already provides. 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 explicitly states the tool's purpose: 'Retrieve Bible verses and passages by reference.' It specifies the exact action ('retrieve'), resource ('Bible verses and passages'), and input method ('by reference'), and distinguishes itself from sibling tools by focusing on Bible content retrieval, unlike other culture tools like art, poetry, or dictionary APIs.

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 usage guidance: it specifies when to use this tool ('Supports single verses, ranges, and multiple references') and implicitly when not to use it (e.g., for non-Bible content or other reference types). It also mentions the source ('Bible API (Public Domain (World English Bible))'), which helps differentiate it from alternatives like Quran or other religious texts in the sibling list.

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