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

Annotations already declare the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description contributes the non-obvious behavioral detail that relations are derived from shared shelves or verses, but it omits what happens when both slug and reference are omitted (no required params) and says nothing about result size or the limit cap.

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 sentence is short and front-loaded, but the appended '[no key]' fragment is unexplained noise that consumes space without adding meaning. Brevity here reflects under-specification rather than disciplined conciseness.

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 values needn't be explained, but the description still leaves the mutual exclusivity/defaulting of slug vs reference, the behavior when neither is supplied, and the limit parameter unaddressed. For a three-parameter tool with 0% schema coverage, this is too thin.

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%, so the description must compensate, but it only loosely names two of the three parameters and adds no format or syntax meaning (what a valid slug or reference looks like). The 'limit' parameter is never mentioned, leaving real coverage gaps on a partially undocumented 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 conveys a meaningful relationship basis (articles sharing a shelf or a verse) and names the two anchor inputs (slug, scripture reference), which distinguishes it from get_article and list_articles. However, it is a noun fragment with no verb, so the operation (find/list related articles) is only implied, and the trailing '[no key]' fragment is opaque.

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 statement of when to use this tool versus siblings such as get_connections_by_book, get_cross_references, or search_articles. The slug-or-reference choice is hinted at structurally but never framed as guidance, and no exclusions or prerequisites are given.

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