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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered structurally. The description adds no behavioral context of its own — no note on result shape, ordering, or coverage — beyond restating the title.

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 phrase 'read a passage at a time' appears twice within two sentences, and the opening sentence duplicates the title verbatim. The second sentence is a padded content listing rather than front-loaded, actionable information.

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 no output schema and no parameters, the description is the only place to explain what the list contains (book identifiers? titles? reading plans?). It never does, preferring a marketing-style catalogue of mythic works, so an agent cannot predict the return shape before calling.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 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 text largely restates the title ('The whole books in the Library that can be read a passage at a time') and never states the verb 'list' or what a caller receives. The second sentence is a content inventory (Greek/Norse myth, Theogony, Iliad) rather than a purpose statement, so an agent cannot easily tell this apart from siblings like list_readings or read_book.

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 explicit when-to-use guidance and no named alternative among siblings (get_reading, list_readings, search_readings). The phrase 'read a passage at a time' faintly implies this enumerates reading-capable books, but the agent is left to infer the selection condition entirely.

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