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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered by structured data. The description adds genuine value beyond that: segment-by-segment alignment, the return shape {n, he, en}, and next/previous section refs for paging. These behavioral details are not available from the annotations or input schema, with no contradictions.

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 purpose is front-loaded in the first sentence, and every following sentence earns its place: scope, reference examples, return structure, paging, and failure fallback. It is a bit dense, but given the heterogeneous reference syntax it must convey, the length is justified with no filler.

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 complex 7-parameter tool with no output schema, the description compensates well by specifying the return segments shape and paging mechanism. The remaining gaps are minor: no guidance on when to prefer get_texts_bulk, and no explanation of how version_title or translation_language interact with the language parameter — but these are partially covered by the 100% schema descriptions.

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 the baseline is 3. The description earns a 4 by substantially enriching the most critical parameter (ref) with nine concrete reference examples covering books, verses, Talmudic folios with segment ranges, and commentaries — far more than the schema's single example provides.

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?

"Fetch any text from the Jewish library by reference" states a specific verb, resource, and retrieval mechanism, and the coverage list (Tanakh, Talmud, Midrash, etc.) and reference examples clearly distinguish it from siblings like browse_library, get_random_text, get_torah_reading, and search_library. An agent can immediately tell this is the by-reference text fetcher, not a browsing or topic-based tool.

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?

The description makes the usage context clear (fetch by structured reference, with nine example formats) and gives an explicit fallback: "If a reference fails, try resolve_name." However, it never states when NOT to use this tool versus close siblings such as get_texts_bulk (bulk fetching) or get_torah_reading (specific structured readings), so exclusions are incomplete.

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