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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the lower bar is met and the description adds genuinely non-obvious behavior: numbered-line output, titles/epigraphs/dedications/stage directions separated from verse, and the rule that a multi-section work yields a section index unless a section number is supplied.

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 return behavior, then usage, then two compact examples. Every sentence carries information (formatting, section logic, scope limits) 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?

With an output schema present, the description needn't restate return fields, and it correctly focuses on behavior an agent can't infer: section-index fallback and content-type marking. Annotations plus schema plus description leave no material gap for correct invocation.

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 baseline is 3; the description still adds value by tying `identifier` formats to concrete, real-looking examples and by showing the combined identifier+section call. It does not add syntax or constraints beyond the schema, so it stops short of a 5.

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?

Opens with a specific verb and resource ("Returns the text of a poem") and immediately scopes it to the ReadingRate collection. It draws a clear boundary against the sibling search/annotation tools by stating it returns only existing collection poems and does not write, continue or translate.

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?

Gives an explicit trigger ("when the user asks to read or see a specific poem, or part of one") and explicit exclusions (no writing, continuing or translating). The section-vs-list behavior is also flagged as a usage condition, so the agent knows when to pass `section`.

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