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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world scope, so the safety profile is covered. The description adds one genuinely behavioral caveat beyond that: deuterocanonical books only exist in Catholic Bibles, which warns of a possible empty result. It still says nothing about output shape, translation labeling, or what happens when a book is absent from the chosen bible.

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 compact and front-loaded, leading with what is returned and then the reference grammar with concrete examples. The trailing Spanish translation line is a small redundancy for a single-language audience but is defensible for a bilingual tool, and no sentence is filler.

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?

With no output schema, the description should ideally describe the returned structure (e.g., verse text vs. a list of ranges, translation metadata), and it does not. The reference grammar and availability caveats are thorough, so an agent can call it correctly, but it cannot anticipate the response shape or error behavior.

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?

Schema coverage is 100%, so the baseline is 3, but the description substantially enriches the ref parameter beyond 'Reference, e.g. MAT 5:1-12' by documenting OSIS-style book ids, chapter:verse range forms, multi-range separation with ';', and Hebrew numbering for Psalms. It also explains the fallback logic behind the bible default, which the schema only hints at.

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 states a specific resource and action: 'Text of a Bible passage', immediately telling the agent this is a retrieval-by-reference tool. It is clear on its own, but it never differentiates itself from the sibling bible_search, so an agent must infer that this tool takes a reference while the sibling takes keywords.

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?

There is no explicit when-to-use guidance, no prerequisites, and no mention of when to prefer bible_search, readings_of_the_day, or mass_of_the_day instead. The only usage-like content is reference syntax and the bible-id default, which is parameter mechanics rather than tool selection guidance.

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