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

Annotations only declare the operation read-only/idempotent; the description adds the no-match fallback, the suicide/self-harm crisis-resource branch, the safety disclaimer, and the exact output shape (NIV passage, prayer text, link). This is substantial behavioral context beyond 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 core action and topic scope are front-loaded; every subsequent sentence covers a necessary use case, output detail, or safety branch. Despite covering several edge cases, it remains a compact block rather than repetitive prose.

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 fully specifies the return format, result count, fallback behaviors, and crisis handling. The only minor gap is behavior when both optional parameters are omitted, which is not needed to invoke the tool correctly in a real user-feeling request.

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 already 100%, so the baseline is 3. The description adds value by clarifying the parameters can be used 'and/or', mapping the enum slugs to human-readable topic names, and explaining the matching semantics that drive fallback behavior.

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?

States a specific action ('looks up scripture prayers in Sanctuary's library') and a concrete resource, with the seven topics enumerated. The described output (up to four prayers with passages and links) separates it from sibling list_prayer_topics even without naming 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?

Gives an explicit trigger: 'Use when the user asks for a prayer, a Bible passage to pray, or words for a feeling' and adds the church-leaving/faith-struggle context. It does not explicitly say when to prefer list_prayer_topics or describe_sanctuary, so it lacks a true alternatives exclusion.

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