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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false, so safety is fully covered by structured data. The description adds that exactly one cross-reference is returned and that relationship attribution is included, but says nothing about auth, rate limits, or error behavior. A 3 fits with annotations carrying the safety burden.

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?

A single, front-loaded sentence with no filler. Every element (verb, cardinality, input scope, attribution) earns its place.

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?

An output schema exists, so return-value detail is not required, but the four required parameters have zero schema descriptions and the description does not fill that gap. For a tool whose inputs determine the entire query, an agent lacks enough information to format source_id and book_id correctly.

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 description coverage is 0% across four required parameters, so the description would need to compensate but does not. It only hints at 'exact verse' and never explains source_id's bsb/web enum, book_id format, or the chapter/verse bounds documented in the schema.

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 uses a specific verb ('Return') and resource ('one sourced cross-reference for an exact verse') and adds a distinguishing scope note ('with relationship attribution'). It is clearly not a comparison or context tool, though it never names which sibling to prefer over it.

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 when-to-use, when-not-to-use, or alternative-tool guidance. The phrase 'for an exact verse' implies a precision requirement but does not tell an agent when this preview is preferable to faith_scripture_lookup or faith_passage_context_preview.

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