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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, providing the safety profile. The description adds valuable behavioral details about input normalization: accepted OSIS/USFM codes, full names, aliases, case-insensitivity, and tolerance for hyphens/underscores. This goes beyond the structured annotations and helps agents invoke the tool correctly. No contradiction found.

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 two sentences: the first states the core purpose, the second elaborates on accepted input formats. Every word earns its place, with no redundant filler. It is front-loaded with the most important information.

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), the rich annotations, and the presence of an output schema, the description covers all necessary context. It transparently explains input flexibility and what the metadata contains, while the output schema handles return-value documentation. No critical gaps remain.

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 already documents the single required parameter 'book_code' with examples. The description enriches this by enumerating accepted formats (OSIS, USFM, full names, aliases) and explicit normalization rules (case-insensitive, hyphen/underscore tolerance). This adds meaning beyond the schema's basic example list, raising it above the baseline of 3.

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 function: 'Get metadata for a single Bible book including chapter and verse counts.' This specific verb+resource combination distinguishes it from siblings like bible.books (list) and bible.chapter (chapter content). The distinction is further reinforced by the words 'single Bible book'.

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: when you need metadata for one specific Bible book. It does not explicitly name alternatives or exclusions, but the scope is unambiguous enough for an agent to infer appropriate usage. It falls short of a 5 because it does not mention alternative tools for related tasks.

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