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

The description adds substantial behavioral context beyond the readOnlyHint annotation: accentuation/case are ignored, reported differences are real variants or spelling variants (e.g., movable Ny), and it reports per-word attestation across eight editions. It also discloses the OT limitation. This exceeds what annotations alone convey.

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 front-loaded with the core action, followed by technical nuances, usage examples, and limitations. Every sentence earns its place, with no repetitive or filler content, and the length is appropriate for the tool's complexity.

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?

For a comparison tool with an output schema, the description covers the essential aspects: what is compared, how differences are normalized, the attestation feature, and the OT limitation. The output format is presumably handled by the output schema, so no 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 input schema already provides full descriptions for all three parameters (100% coverage), including the German NT book naming convention. The description adds no additional parameter-specific semantics beyond the schema, so the baseline of 3 is appropriate.

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: 'Compare one NT verse word-by-word across the Greek editions... and list the textual differences.' This specific verb+resource distinguishes it from siblings like bible_lookup or bible_search, and the mention of per-word attestation further clarifies the scope.

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?

Explicit usage guidance is provided: 'Use for questions about textual variants (e.g. the Comma Johanneum, 1Jn 5:7).' It also gives a clear exclusion: 'OT verses have only one edition (WLC) and cannot be compared.' This tells the agent exactly when to select this tool over alternatives.

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