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 goes further by disclosing the return shape — articles containing an excerpt, summary points and a link — which is the non-obvious behavior here (asking for verses yields curated articles, not a verse list).

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?

Two sentences, front-loaded with the action and immediately followed by what is returned. Slightly wasteful only in that the subject examples overlap the schema's example list.

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 two-parameter lookup with full schema coverage and complete annotations, this is nearly complete; it even covers the otherwise-unstated return contents. The only unaddressed point is whether subject matching is keyword or semantic, which matters for phrasing a query.

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 in the schema, including the 1–10 limit and subject length bounds. The description's subject examples (anxiety, hope, forgiveness, marriage) reinforce but do not extend the schema's own example "anxiety" or "losing a parent", so the baseline 3 applies.

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 names a specific verb and resource ("Find Bible verses") and, crucially, explains that results are Christian Pure articles that gather and explain verses rather than raw verse text. That distinguishes it in spirit from search_articles or get_article, though it never names a sibling explicitly.

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?

Usage is only implied: an agent can infer it should be called when the user wants verses on a topic like anxiety or loss. There is no statement of when to prefer search_articles or get_article instead, and no exclusions or prerequisites.

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