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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds context those fields cannot: the 50-verse hard cap, the fact that text is verbatim and unchanging, and per-translation licensing (KJV public domain outside the UK; WEB public domain) that an agent needs for attribution. No error or failure behavior is described.

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?

Front-loaded with the capability, then the size limit, then formats, then provenance and licensing — a sensible order with no preamble. The licensing sentence is the longest and is lower-value for invocation, though defensible for a scripture source; the capability and example lists slightly overlap with the schema.

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 only two parameters, full schema coverage and a complete annotation set, the definition covers what an agent needs to construct a call. Since there is no output schema, the description should say something about the shape of the return (verse text with reference labels, ordering for ranges, etc.), and it does not; failure modes for unparseable references are also unstated.

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 both parameters are already documented, including the KJV/WEB enum, the KJV default, the 64-char limit and the same three example references. The description only adds the expansion of WEB to "World English Bible", which is marginal. Baseline 3 applies when the schema does the work.

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?

Names a specific verb (look up) and resource (Bible verse), then bounds the scope precisely: a single verse, a range within one chapter, or an entire chapter. The arbitrary-reference scope plus the named translations makes it distinguishable at a glance from todays_reflection and verse_of_the_day, which return a fixed daily passage.

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?

It states an operational rule for large requests ("At most 50 verses per call; split longer passages") and gives three example reference formats, which tells the agent what it can ask for. It never says when to prefer this tool over the two siblings, nor when not to use it, so routing must be inferred from the names alone.

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