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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds nothing behavioral beyond the title phrase "line by line" — no indication of what the response looks like, whether a plan expands into multiple lines, or what happens for an unknown id. A single required id makes authorization/rate-limit notes less critical, but nothing extra is disclosed.

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 where the first duplicates the title outright and the second is a semicolon-and-comma clause salad mixing unrelated capabilities (daily verses, plans, search, verse lookup, library books). Nothing is front-loaded usefully and the sentence does not earn its space.

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?

There is no output schema, so the description must at least sketch what comes back and how a plan versus a reading differs — it does neither, offering only the vague "line by line". Combined with the missing distinction from the eight sibling tools taking similar identifiers, the definition is not complete enough to call the tool confidently.

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 100% for the single parameter, which already explains that id comes from /readings or is a plan name like "japji". The description contributes no additional syntax, format or lookup semantics, 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 first sentence is a verbatim restatement of the tool title ("One reading or plan, line by line") and never says the tool retrieves/fetches a single reading or plan by id. The second sentence then lists domain features (daily verses, search, verse lookup, whole books) that belong to sibling tools like search_readings, get_verse and read_book, muddying rather than clarifying what this tool does. No differentiation from siblings is achieved.

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 when-to-use statement and no routing rule against alternatives. Naming "search and verse lookup" and "whole books from the Library" hints at sibling capabilities but is never framed as "use X instead", so the agent gets no signal for choosing get_reading over search_readings, get_verse, get_chapter or read_book.

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